54 results on '"Nakaakira Tsukahara"'
Search Results
2. Physiological Identification of Midbrain Neurons Related to Lens Accommodation in Cats.
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TAKEHIKO BANDO, KENJI TSUKUDA, NOBUHIKO YAMAMOTO, JUN MAEDA, and NAKAAKIRA TSUKAHARA
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- 1984
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Catalog
3. Quantitative analysis of electrical properties of dendritic spines
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Mitsuo Kawato, Fujio Murakami, Nakaakira Tsukahara, and Takahiro Hamaguchi
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Neuronal Plasticity ,Dendritic spine ,General Computer Science ,Chemistry ,Models, Neurological ,Electric Conductivity ,Dendrite ,Dendrites ,Axonal Transport ,Synapse ,Electrophysiology ,medicine.anatomical_structure ,Spinal Cord ,Postsynaptic potential ,Synapses ,Synaptic plasticity ,Excitatory postsynaptic potential ,medicine ,Animals ,sense organs ,Neuron ,Neuroscience ,Horseradish Peroxidase ,Biotechnology - Abstract
Several suggestions have been made with regard to the functional significance of dendritic spines in connection with synaptic plasticity. We have shown that for a constant synaptic current, when the synaptic resistance is large compared to the spine-stem resistance, a morphological change in the spine does not produce a marked change in the postsynaptic potential (PSP). When the synaptic resistance is comparable to the spine-stem impedance a morphological change in the spine can induce changes in the synaptic current and the PSP due to the so-called nonlinear effect to the synapse (Kawato and Tsukahara, 1983, 1984). Consequently, in a study of the electrical properties of dendritic spines the input impedance of the parent dendrite, the spinestalk conductance and the conductance change associated with synaptic activity must be considered. We quantitatively estimated all three factors. By comparing electrophysiological data with morphological data, we estimated the synaptic conductance which causes corticorubral EPSP. Its maximum amplitude was 43 nS with a time-to-peak value of 0.3 ms. With this value, the effects of the spine were examined using an improved algorithm based on that of Butz and Cowan (1974). It uses a three-dimensional morphology of the rubrospinal (RS) neurons, which was reconstructed from serial sections containing HRP-filled RS cells. As the spine shortens, the amplitude of the EPSP becomes considerably larger, but its time-to-peak value does not markedly change. Moreover, if unitary EPSP in the RS cell is produced by the activation of several synaptic terminals a morphological change of the spine has a smaller effect on the EPSPs. more...
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- 1984
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4. Physiological properties of the newly formed cortico-rubral synapses of red nucleus neurons due to collateral sprouting
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Y. Fujito, Fujio Murakami, and Nakaakira Tsukahara
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Cerebral Cortex ,Red nucleus ,General Neuroscience ,Electric Conductivity ,Biology ,Collateral sprouting ,Electric Stimulation ,Nerve Regeneration ,Cerebellar Nuclei ,Nerve Degeneration ,Neural Pathways ,Synapses ,Cats ,Animals ,Neurology (clinical) ,Evoked Potentials ,Molecular Biology ,Neuroscience ,Red Nucleus ,Developmental Biology - Published
- 1976
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5. Appearance of new synaptic potentials at cortico-rubral synapses after the establishment of classical conditioning
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Yoichi Oda and Nakaakira Tsukahara
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General Physics and Astronomy ,Classical conditioning ,General Medicine ,Biology ,General Agricultural and Biological Sciences ,Neuroscience - Published
- 1981
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6. Neural mechanisms of learning and memory
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Nakaakira Tsukahara
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General Chemical Engineering - Published
- 1985
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7. Actin filaments in dendritic spines of red nucleus neurons demonstrated by immunoferritin localization and heavy meromyosin binding
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Hironobu Katsumaru, Fujio Murakami, and Nakaakira Tsukahara
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Actin remodeling of neurons ,Dendritic spine ,Heavy meromyosin ,Chemistry ,Red nucleus ,General Medicine ,General Biochemistry, Genetics and Molecular Biology ,Actin ,Cell biology - Published
- 1982
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8. Synaptic Inputs of the Red Nucleus Neurons in the Cat
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Y. Fujito, Jun Maeda, Nakaakira Tsukahara, and Yoichi Oda
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Chemistry ,Red nucleus ,General Physics and Astronomy ,General Medicine ,General Agricultural and Biological Sciences ,Neuroscience - Published
- 1978
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9. Interpositus neurons controlling lens accommodation
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Takehiko Bando, Nakaakira Tsukahara, and Akira Ishihara
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medicine.anatomical_structure ,Optics ,business.industry ,Lens (anatomy) ,medicine ,General Physics and Astronomy ,General Medicine ,Biology ,General Agricultural and Biological Sciences ,business ,Accommodation - Published
- 1979
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10. Promotion of sprouting and synaptogenesis of cerebrofugal fibers by ganglioside application in the red nucleus
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S. Watanabe, Nakaakira Tsukahara, H. Kobayashi, and Y. Fujito
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medicine.medical_specialty ,Time Factors ,Red nucleus ,Central nervous system ,Synaptogenesis ,Stimulation ,Biology ,Midbrain ,Gangliosides ,Internal medicine ,medicine ,Animals ,Evoked Potentials ,Red Nucleus ,Ganglioside ,General Neuroscience ,Somatosensory Cortex ,General Medicine ,Axons ,Nerve Regeneration ,Electrophysiology ,Endocrinology ,medicine.anatomical_structure ,Cerebral cortex ,Synapses ,Cats ,Cattle ,Neuroscience ,Sprouting - Abstract
The effect of gangliosides on sprouting of cerebrorubral synapses from the contralateral cerebral cortex was investigated following lesions of normal ipsilateral cerebrorubral synapses. It was found that, in cats in which ipsilateral cerebral ablations were performed at more than 2 months of age, the mean probability of occurrence of EPSPs induced in red nucleus neurons by stimulation of fibers from the contralateral cerebral cortex in the ganglioside-treated group was significantly higher than in the untreated group. Therefore, ganglioside application appears to promote sprouting and formation of functional synapses in the red nucleus. more...
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- 1985
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11. Morphological and electrophysiological study of sprouting of corticorubral fibers after lesions of the contralateral cerebrum in kitten
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Nakaakira Tsukahara, Y. Fujito, E. Kosar, and Fujio Murakami
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Nerve Crush ,Biology ,Synaptic Transmission ,Kitten ,Evoked Potentials, Somatosensory ,biology.animal ,Cortex (anatomy) ,Reaction Time ,medicine ,Animals ,Molecular Biology ,Horseradish Peroxidase ,Red Nucleus ,Cerebral Cortex ,Neuronal Plasticity ,Pyramidal tracts ,Post-tetanic potentiation ,Cerebrum ,General Neuroscience ,Cerebral peduncle ,Motor Cortex ,Anatomy ,Electric Stimulation ,Nerve Regeneration ,Electrophysiology ,medicine.anatomical_structure ,Synapses ,Cats ,Excitatory postsynaptic potential ,Neurology (clinical) ,Developmental Biology - Abstract
The appearance of crossed corticorubral projections following ablations of the ipsilateral cortex is shown to result from the formation of new connections and is not due to the preservation of pre-existing bilateral connections. At least some of these crossed projections are collaterals of the pyramidal tract. Post-tetanic potentiation can be demonstrated both intra- and extracellularly following ipsilateral cerebral peduncle stimulation whereas no changes in excitatory postsynaptic potential amplitude are observed following contralateral cerebral peduncle stimulation. more...
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- 1985
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12. The Cerebellar Control of Accommodation of the Eye in the Cat
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Minoru Hosoba and Nakaakira Tsukahara
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medicine.medical_specialty ,business.industry ,Ophthalmology ,medicine ,General Medicine ,business ,Accommodation - Published
- 1976
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13. Synaptic Plasticity in the Mammalian Central Nervous System
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Nakaakira Tsukahara
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Central Nervous System ,Mammals ,Neurons ,Aging ,Synaptic scaling ,General Neuroscience ,Cell Membrane ,education ,Nonsynaptic plasticity ,Neurophysiology ,Biology ,Denervation ,Synaptic Transmission ,Axons ,Membrane Potentials ,Synaptic fatigue ,Homeostatic plasticity ,Nerve Degeneration ,Synapses ,Synaptic plasticity ,Metaplasticity ,Animals ,Developmental plasticity ,Neuroscience - Abstract
More than a decade has passed since Kandel & Spencer (1968) in their excellent review discussed cellular neurophysiological approaches to the study of learning. The understanding of plasticity, defined as any persistent change in the functional properties of single neurons or neuronal aggre gates, is a prerequisite for the neurophysiological study of learning. Since 1968, we have increased greatly our understanding of the nature of these plastic changes in the central nervous system. This paper reviews this recent literature. In particular I focus on four areas. more...
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- 1981
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14. Physiological evidence of formation of new synapses from cerebrum in the red nucleus neurons following cross-union of forelimb nerves
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Y. Fujito and Nakaakira Tsukahara
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Red nucleus ,Cerebrum ,Muscles ,General Neuroscience ,Anatomy ,Biology ,Electric Stimulation ,Nerve Regeneration ,medicine.anatomical_structure ,Physical Stimulation ,Forelimb ,Synapses ,Cats ,medicine ,Animals ,Brachial Plexus ,Neurology (clinical) ,Evoked Potentials ,Molecular Biology ,Neuroscience ,Muscle Contraction ,Red Nucleus ,Developmental Biology - Published
- 1976
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15. Associative conditioning mediated by the red nucleus in the cat
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Tatsuto Notsu, Yoichi Oda, and Nakaakira Tsukahara
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Associative conditioning ,Red nucleus ,Chemistry ,General Physics and Astronomy ,General Medicine ,General Agricultural and Biological Sciences ,Neuroscience - Published
- 1979
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16. Some properties of the theoretical membrane transients in Rall's neuron model
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Shunsuke Sato and Nakaakira Tsukahara
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Neurons ,Statistics and Probability ,Membrane potential ,Physics ,General Immunology and Microbiology ,Applied Mathematics ,Models, Neurological ,Mathematical analysis ,Time constant ,Biological neuron model ,General Medicine ,General Biochemistry, Genetics and Molecular Biology ,Membrane Potentials ,Exponential function ,Amplitude ,medicine.anatomical_structure ,Modeling and Simulation ,Cats ,medicine ,Calculus ,Animals ,Cylinder ,Neuron ,General Agricultural and Biological Sciences ,Compartment (pharmacokinetics) - Abstract
Theoretical membrane potential transient produced by applying a current step to nerve cells has been derived based on the compartment neuron model and also on the equivalent cylinder model developed by W. Rall. It is expressed as a sum of exponential functions as ∑i=0n−1 Ei[1−exp(tτi)] where n is the number of compartments. The ratio of the amplitudes of the first and the second largest exponential functions, (E1E0), was found to be proportional to that of their respective time constants, (τ1τ0), in these neuron models. The constant of proportionality is given in a form that depends on the number of compartments as E1E0 = (1 + cosπn)τ1τ0. This theoretical result is discussed in the light of recent experimental results in cat red nucleus neurons. more...
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- 1976
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17. Brain plasticity: The themes and case studies of neuro-biophysics
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Nakaakira Tsukahara
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Neurons ,Aging ,Red nucleus ,Models, Neurological ,Biophysics ,Brain ,Classical conditioning ,Biological neuron model ,Dendrites ,Anatomy ,Biology ,Neurotransmission ,Biochemistry ,Electrophysiology ,Microscopy, Electron ,Synapses ,Synaptic plasticity ,Neuroplasticity ,cardiovascular system ,Animals ,Neuroscience ,Mathematics ,Red Nucleus ,Sprouting - Abstract
After a brief overview of the current status of our understanding of synaptic plasticity and sprouting in the brain, sprouting in the cat red nucleus was described in detail as a model system. As the basis of our investigations of sprouting in the RN, light and electron microscopic studies, together with computer analysis of dendritic geometry by a digital image processing system, were reported. Electrophysiology using both in vivo and in vitro preparations was described; a model study using Rall's mathematical neuron model was presented. Based on these data, lesion-induced sprouting and the formation of functional synapses at an early developmental stage were investigated. This was compared with lesion-induced sprouting in adults. The synaptic transmission of synapses newly-formed by sprouting was investigated in detail. It was also reported that sprouting takes place in the absence of lesions to central neurons, in a preparation where peripheral flexor and extensor nerves were surgically crossed (cross-innervation). Finally, an attempt to correlate cortico-rubral sprouting with behavioral plasticity, using classical conditioning, was presented. more...
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- 1982
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18. Synaptic Plasticity in the Central Nervous System
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Nakaakira Tsukahara
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medicine.anatomical_structure ,business.industry ,Synaptic plasticity ,Central nervous system ,medicine ,Surgery ,Neurology (clinical) ,business ,Neuroscience - Published
- 1977
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19. Properties of cerebello-precerebellar reverberating circuits
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Fujio Murakami, Nakaakira Tsukahara, Takehiko Bando, and Yoichi Oda
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Cerebellum ,Red nucleus ,Stimulation ,Olivary Nucleus ,Tonic (physiology) ,Cerebellar Cortex ,Pons ,medicine ,Animals ,Molecular Biology ,Red Nucleus ,Chemistry ,Reticular Formation ,General Neuroscience ,Cerebral peduncle ,Depolarization ,Electric Stimulation ,Electrophysiology ,medicine.anatomical_structure ,Cerebellar Nuclei ,nervous system ,Cats ,Axon reflex ,Neurology (clinical) ,Neuroscience ,Nucleus ,Brain Stem ,Developmental Biology - Abstract
Intracellular recordings were made from neurons of the red nucleus (RN) in cats where the cerebellar cortical effects were removed by chronic ablation of the intermediate part of the anterior lobe of the cerebellum. A prolonged depolarization could be elicited by stimulating the nucleus interpositus (IP) of the cerebellum, nucleus reticularis tegmenti pontis (NRTP) and the nucleus reticularis paramedianus (PMRN). This prolonged depolarization was abolished after cooling the inferior and middle cerebellar peduncles and persisted after ablation of the cerebral sensorimotor cortex. The prolonged depolarization was also recorded intracellularly from IP neurons. It was concluded that the prolonged depolarization set up in RN neurons is due to the repetitive discharges of IP neurons which produces tonic bombardment onto RN cells. The mechanisms of the repetitive discharges of IP neurons are considered to be due to impulse reverberation via the IP. The dynamic properties of the reverberating circuits were characterized by regenerative behavior. Above and below threshold, there were two states, the excited state where many constituent neurons were active, and the resting state where all neurons were inactive. It was found that cats with chronically stimulated cerebral peduncle (CP), and tested in an acute experiment, showed sometimes effective for inducing the prolonged depolarization and repetitive discharges of RN neurons by stimulation of IP. The prolonged depolarization thus produced could be reversibly abolished by cooling the middle and inferior cerebellar peduncles. The possible constituent neurons of the reverberating circuits were investigated in light of previous physiological investigations of stimulating the NRTP, PMRN, nucleus reticularis lateralis (LRN), nucleus olivaris inferior (IO) and recording EPSPs in RN cells. The RN cells receive axon reflex activation from NRTP and PMRN, and disynaptic excitation from NRTP, PMRN, LRN and IO. Based on these and other available data, the components of the cerebello-precerebellar reverberating circuits are discussed. more...
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- 1983
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20. Sprouting and the neuronal basis of learning
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Nakaakira Tsukahara
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Neuronal sprouting ,nervous system ,Red nucleus ,General Neuroscience ,Neuroplasticity ,Biology ,Neuroscience ,Cultured neuronal network ,Sprouting - Abstract
The phenomenon of neuronal sprouting in the red nucleus offers a unique opportunity to study neuronal plasticity and its relationship to behaviour, in particular learning and memory.
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- 1981
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21. Modification of rubral unit activities during classical conditioning in the cat
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Nakaakira Tsukahara, Shinji Miyasaka, Kazuhiro Kuwa, and Yoichi Oda
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Control theory ,General Physics and Astronomy ,Classical conditioning ,General Medicine ,Biology ,General Agricultural and Biological Sciences ,Unit (ring theory) - Published
- 1981
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22. The cerebellar control of the pupillary light reflex in the cat
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Y. Ijichi, Nakaakira Tsukahara, T. Kiyohara, and Minoru Hosoba
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Cerebellum ,Light ,business.industry ,General Neuroscience ,Stimulation ,Stimulus (physiology) ,Reflex, Pupillary ,Deep cerebellar nuclei ,Pupil ,medicine.anatomical_structure ,Cerebellar Nuclei ,Pupillary reflex ,Cats ,Reaction Time ,Pupillary response ,Animals ,Medicine ,Neurology (clinical) ,Pupillary light reflex ,business ,Evoked Potentials ,Molecular Biology ,Neuroscience ,Developmental Biology - Abstract
The effect of cerebellar lesions upon the pupillary light reflex was examined in anesthetized cats. The pupillary response elicited by a step and sinusoidally modulated light stimulus was used. In acute cerebellectomized cats, the high frequency cutoff of the frequency response of the pupillary reflex was moved to a lower level after cerebellar lesions. Selective lesions were made in the deep cerebellar nuclei and the frequency responses of the pupillary reflex were compared. The fastigial lesions produced the most prominent change in the frequency responses. Electrical stimulation of the deep cerebellar nuclei, especially the fastigial nuclei, induced pupillary dilatation. Thus the cerebellum appears to participate in the control of the pupillary light reflex by improving the frequency responses of the pupil so that it can follow changing light stimuli better, and this control is exerted via the bilateral fastigial nuclei. more...
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- 1977
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23. The mode of cerebellar control of pupillary light reflex
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Nakaakira Tsukahara, Yoshichika Ijichi, and Toshikazu Kiyohara
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medicine.medical_specialty ,business.industry ,General Neuroscience ,Reflex, Pupillary ,Cerebellar Nuclei ,Cerebellum ,Pupillary reflex ,Ophthalmology ,Cats ,Animals ,Medicine ,Neurology (clinical) ,Corneal reflex ,Pupillary light reflex ,business ,Molecular Biology ,Photic Stimulation ,Developmental Biology - Published
- 1973
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24. The properties of the cerebello-pontine reverberating circuit
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Nakaakira Tsukahara
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Membrane potential ,CATS ,Red nucleus ,General Neuroscience ,Action Potentials ,Cerebellopontine Angle ,Neurotransmission ,Cerebellopontine angle ,Synaptic Transmission ,Electrodes, Implanted ,Membrane Potentials ,chemistry.chemical_compound ,Nuclear magnetic resonance ,Cerebellar Nuclei ,chemistry ,Neural Pathways ,Cats ,Animals ,Picrotoxin ,Neurology (clinical) ,Molecular Biology ,Red Nucleus ,Developmental Biology - Published
- 1972
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25. Release of endogenous GABA from the cat red nucleus slices
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Hironobu Sakaguchi, Nakaakira Tsukahara, and Michinori Kubota
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Red nucleus ,General Neuroscience ,Endogeny ,Depolarization ,In Vitro Techniques ,Inhibitory neurotransmitter ,Perfusion ,Kinetics ,chemistry.chemical_compound ,Slice preparation ,nervous system ,chemistry ,Cats ,Potassium ,Biophysics ,Tetrodotoxin ,Animals ,Neurology (clinical) ,Evoked Potentials ,Molecular Biology ,Neuroscience ,gamma-Aminobutyric Acid ,Red Nucleus ,Developmental Biology - Abstract
The release of endogenous γ-aminobutyric acid (GABA) from the cat red nucleus was studied in a slice preparation. Potassium-induced depolarization caused a release of GABA in a calcium-dependent manner. The release of GABA was also induced by veratrine and blocked by tetrodotoxin. The demonstration of release satisfies one of the important criteria for identification of GABA as the inhibitory neurotransmitter. more...
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- 1983
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26. Synaptic inputs of feline rubrospinal neurons from the parietal association cortex, pretectum and medial lemniscus, and their lesion-induced sprouting
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Y. Fujito, Jun Maeda, Fujio Murakami, and Nakaakira Tsukahara
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Cerebellum ,Physiology ,Red nucleus ,Pyramidal Tracts ,Mesencephalon ,Cortex (anatomy) ,Parietal Lobe ,medicine ,Animals ,Evoked Potentials ,Red Nucleus ,Pyramidal tracts ,Chemistry ,musculoskeletal, neural, and ocular physiology ,Cerebral peduncle ,Medial lemniscus ,General Medicine ,Membrane hyperpolarization ,Anatomy ,Denervation ,medicine.anatomical_structure ,nervous system ,Spinal Cord ,Cerebral cortex ,Synapses ,Cats ,Neuroscience ,Brain Stem - Abstract
Synaptic inputs of rubrospinal (RN) neurons from the cerebral cortex, pretectal area (PRT), and medial lemniscus (ML) were investigated electrophysiologically in the cat. Stimulation of the ipsilateral parietal association cortex (PASC) and secondary sensory area (SII) produced slow-rising about 3 msec rise time monosynaptic EPSPs which were, in some cases, followed by hyperpolarizations, similar to the sensorimotor cortex (SM)-induced PSPs previously observed. Stimulation of the contralateral cerebral cortex never produced detectable PSPs. Topographical arrangement of PASC-rubral projection was found. Stimulation of the lateral part of PASC induced EPSPs predominantly in RN cells innervating the cervicothoracic spinal segments, while stimulation of the medial part of PASC produced EPSPs predominantly in RN cells innervating the lumbosacral cord. Furthermore, PASC-induced EPSPs were more frequently recorded at the rostral half of RN than at the caudal half. Monosynaptic EPSPs and multisynaptic IPSPs were induced by stimulation of the ipsilateral PRT and ML. PRT- and ML-induced EPSPs had times-to-peak of 1.0 +/- 0.4 msec (mean +/- S.D.) and 1.6 +/- 0.5 msec, respectively, which were intermediate to those of the cerebral peduncle (CP)- and nucleus interpositus of the cerebellum (IP)-induced EPSPs. Furthermore, sensitivity of amplitudes of PRT-induced EPSPs to membrane hyperpolarization was intermediate to those of CP- and IP-EPSPs, and that of ML-induced EPSPs was lower than that of IP-EPSPs. Therefore, it is likely that synapses of PRT and ML fibers are formed between the distal dendrites where CP-rubral synapses terminate and soma where IP-rubral synapses terminate. PASC-induced EPSPs after chronic IP and SM lesions had a new fast-rising component and the effectiveness of ML stimulation to induce the unit spike of RN cells was clearly increased in IP and SM lesioned cats. It was suggested that PASC-rubral fibers sprouted and formed new synapses at the proximal portions of soma-dendritic membranes of RN cells after IP and SM destructions. Collateral fibers to RN cells of the pyramidal tract were also shown to sprout new synapses following IP and ML lesions. more...
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- 1983
27. Dynamic and Plastic Properties of the Brain Stem Neuronal Networks as the Possible Neuronal Basis of Learning and Memory
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Nakaakira Tsukahara and Mitsuo Kawato
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Developmental stage ,Synaptic weight ,Artificial neural network ,Computer science ,Fixed action pattern ,Rigidity (psychology) ,Plasticity ,Neuroscience ,Cultured neuronal network - Abstract
It has long been believed that nerve connections in the brain are stable and rigid after their formation at an early developmental stage. However, although this rigidity of the nerve connections probably provides an important basis for instinctive behaviors, as the built-in generator of fixed action pattern, it cannot readily account for any kinds of adaptive behaviors, such as learning and memory. In this context it has recently been recognized that some of the nerve connections of the brain have plasticity. That is, they can be modified to some extent. This “plasticity” is thought to be the neural basis for adaptive behaviors. In other words, the “plasticity” and “rigidity” of the neural networks may relate to the environmental versus genetic factors which underlie behavior. more...
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- 1982
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28. Sprouting as a Basis for Classical Conditioning in the Cat
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Nakaakira Tsukahara, Yoichi Oda, and Fujio Murakami
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Behavioral plasticity ,Period (gene) ,Classical conditioning ,Long-term potentiation ,Neurotransmission ,Biology ,Plasticity ,Neuroscience ,Sprouting - Abstract
Plasticity of synaptic transmission is thought to underlie behavioral plasticity in invertebrates. In mammals, circumstantial evidence has been accumulating to suggest that long-term potentiation of synaptic transmission contributes to behavioral plasticity (e.g., Morris et al., 1986). Although long-term potentiation lasts for many days, some other mechanisms should be considered to explain behavioral modification that is retained for a much longer period. more...
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- 1988
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29. Effects of amino acids on cat red nucleus neurons in vitro
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H. Sakaguchi, Nakaakira Tsukahara, Masanori Nakamura, and Michinori Kubota
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Red nucleus ,Glycine ,Glutamic Acid ,Neurotransmission ,Inhibitory postsynaptic potential ,Synaptic Transmission ,Slice preparation ,Glutamates ,Postsynaptic potential ,Culture Techniques ,Animals ,Magnesium ,Amino Acids ,Evoked Potentials ,gamma-Aminobutyric Acid ,Red Nucleus ,Neurons ,Aspartic Acid ,Dose-Response Relationship, Drug ,Chemistry ,General Neuroscience ,Depolarization ,Electrophysiology ,nervous system ,Cats ,Biophysics ,Excitatory postsynaptic potential ,Calcium ,Neuroscience - Abstract
Intracellular records were obtained from neurons in the region of the red nucleus (RN) of cat brain slices. Both EPSPs and IPSPs were recorded in response to local electrical stimulation and these resembled similar electrophysiological responses observed in experiments conducted in vivo. Monosynaptic and polysynaptic IPSPs were observed, suggesting the existence of inhibitory interneurons near or within the RN region. When added to the bathing solution, L-glutamate and L-aspartate depolarized RN neurons with a decrease in input resistance. gamma-Aminobutyric acid (GABA) and glycine hyperpolarized the cells with a decrease in input resistance. GABA also elicited a depolarizing response. These amino acid actions had direct postsynaptic effects, since the experiments were conducted in a low Ca2+/high Mg2+ medium which blocked synaptic transmission. more...
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- 1984
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30. Afterhyperpolarization in neurones of the red nucleus
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Fujio Murakami, Nakaakira Tsukahara, H. Hultborn, and B. Gustafsson
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Membrane potential ,Cell Membrane Permeability ,Time Factors ,Red nucleus ,Chemistry ,General Neuroscience ,Models, Neurological ,Action Potentials ,Conductance ,Afterhyperpolarization ,Depolarization ,Hyperpolarization (biology) ,Synaptic Transmission ,Membrane Potentials ,Electrophysiology ,Cats ,Potassium ,Animals ,Reversal potential ,Neuroscience ,Extrapyramidal Tracts ,Red Nucleus - Abstract
Afterhyperpolarization (AHP) following single or short trains of spikes in rubrospinal neurones (RN neurones) of the cat has been studied with intracellular recording techniques. The AHP amplitude was potential dependent; it increased with depolarization and decreased with hyperpolarization and had an extrapolated reversal potential about 20 mV below resting membrane potential. The AHP was associated with an increase in the membrane conductance and it was concluded that the AHP is primarily caused by an increase in membrane conductance to potassium ions. The time course of the conductance change underlying the AHP was measured with short current pulses and calculated from the AHP voltage. The AHP following a single spike was conditioned at different interspike intervals by a preceding spike (or several spikes). In many RN neurones the AHP (conductance) following a spike added approximately linear to that generated by a preceding spike. In most cells, however, the AHP following a spike was instead depressed by a preceding spike. The summation of AHPs increased progressively, while the depression appeared to be already maximal with one preceding spike. The depression was then approximately constant for interspike intervals less than the AHP duration. It will be shown in a following paper that these properties of the AHP are reflected in the behaviour of the repetitive discharge evoked by constant current pulses in the same neurones. more...
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- 1984
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31. The neuronal pathway subserving the pupillary light reflex
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Kensaku Mori, Nakaakira Tsukahara, and H. Hultborn
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Superior Colliculi ,Optic tract ,Accommodation reflex ,Reflex, Pupillary ,Synaptic Transmission ,Posterior commissure ,Nerve Fibers ,Oculomotor Nerve ,Cerebellum ,Animals ,Visual Pathways ,Pupillary light reflex ,Pretectal area ,Molecular Biology ,Evoked Potentials ,Neurons ,Brain Mapping ,Chemistry ,General Neuroscience ,Ciliary Body ,Cerebral Aqueduct ,Ciliary ganglion ,Geniculate Bodies ,Optic Nerve ,Anatomy ,Electric Stimulation ,Pupillary reflex ,Reflex ,Cats ,Neurology (clinical) ,Neuroscience ,Developmental Biology - Abstract
The pupillary light reflex was investigated using electrical stimulation along the pathway and recording in the short ciliary nerves. The discharge of single units in the ciliary ganglion was compared during diffuse light stimuli and electrical stimuli. It was concluded that the early reflex discharge in the short ciliary nerves following electrical stimulation on the optic tract is due to excitation of fibres active during the pupillary light reflex. The light reflex is conveyed by slow (less than 10 m/sec) optic tract fibres which synapase in the medial part of the pretectal area. In turn, pretectal neurones with conduction velocities of about 6 m/sec pass to the Edinger-Westphal complex from which the preganglionic 'pupilloconstrictor' neurones originate. Latency measurements show that there are synapses in the pretectal region and the Edinger-Westphal nucleus. The amplitude of the 'pupilloconstrictor' responses in the short ciliary nerves can be used as a measure of the excitability in the pathway of the pupillary light reflex under various conditions, e.g. following conditioning stimuli of other interacting pathways. In addition to the 'pupilloconstrictor' response there is also another short-latency discharge in the short ciliary nerves following stimulation of the posterior commissure and the Edinger-Westphal nucleus. That discharge is presumably due to activation of fibres which cause accommodation of the lens. more...
- Published
- 1978
32. Mesencephalic neurons controlling lens accommodation in the cat
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Jun Maeda, Kenji Tsukuda, Nakaakira Tsukahara, Nobuhiko Yamamoto, and Takehiko Bando
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Cerebellum ,genetic structures ,Biology ,Midbrain ,Posterior commissure ,Oculomotor Nerve ,Mesencephalon ,Lens, Crystalline ,medicine ,Animals ,Molecular Biology ,Evoked Potentials ,Neurons ,CATS ,General Neuroscience ,Electric Conductivity ,Edinger–Westphal nucleus ,Anatomy ,Axons ,medicine.anatomical_structure ,nervous system ,Lens (anatomy) ,Cats ,Silent period ,Neurology (clinical) ,Nucleus ,Developmental Biology - Abstract
Thirty units were found in the midbrain of the anesthetized cat which discharged in correlation with spontaneously occurring lens accommodation. The frequency of spike potentials increased before the onset of the accommodation response. Increased discharges were followed by a silent period. These units were driven orthodromically by stimulating the interpositus nucleus of the cerebellum and the posterior commissure. Eleven of these units were identified antidromically as parasympathetic oculomotor neurons. more...
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- 1981
33. Electrical constants of neurons of the red nucleus
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Fujio Murakami, Nakaakira Tsukahara, and H. Hultborn
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Neurons ,Membrane potential ,Time Factors ,Red nucleus ,Chemistry ,General Neuroscience ,Cell ,Linear summation ,Dendrites ,Spinal cord ,Membrane Potentials ,medicine.anatomical_structure ,Membrane ,Cats ,medicine ,Biophysics ,Animals ,Current (fluid) ,Neuroscience ,Mathematics ,Red Nucleus ,Input resistance - Abstract
Membrane electrical constants have been studied in neurons of the red nucleus (RN) of the cat which were identified antidromically from the spinal cord. For each cell, the input resistance was determined from the membrane potential changes to current steps and was found to be 2.5+/-0.9 Momega in twenty five RN cells studied. In addition, linear summation of the membrane responses induced by two current pulses was demonstrated. 2. From the membrane voltage transients to current steps, the first membrane time constant, tau0, and second time constant, tau1, were determined as 5.6+/-1.0 msec and 0.6+/-0.2 msec, respectively. The ratio of the amplitudes of two exponential functions, E1/E0, was 0.18+/-0.05. A linear relation was found between the ratio of these amplitudes of exponential functions and that of the two time constants. 3. The cable parameter (electrotonic length, L) of the combined soma and dendrites of the RN neutrons was estimated as 1.1 from membrane transient data using the relation developed by Rall (1969). 4. By using this parameter, an attempt was made to estimate the location of the two excitatory inputs on the soma-dendritic membrane of RN cells. more...
- Published
- 1975
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34. Physiological identification of midbrain neurons related to lens accommodation in cats
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Kenji Tsukuda, Nobuhiko Yamamoto, J. Maeda, Nakaakira Tsukahara, and Takehiko Bando
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Physiology ,Autonomic Fibers, Preganglionic ,Central nervous system ,Iris ,Biology ,Reflex, Pupillary ,Midbrain ,Mesencephalon ,Parasympathetic Nervous System ,Lens, Crystalline ,medicine ,Carnivora ,Animals ,Evoked Potentials ,Neurons ,Brain Mapping ,CATS ,business.industry ,General Neuroscience ,Accommodation, Ocular ,Ganglia, Parasympathetic ,Electric Stimulation ,Electrophysiology ,medicine.anatomical_structure ,Cerebellar Nuclei ,Lens (anatomy) ,Cats ,business ,Accommodation ,Neuroscience - Abstract
Single units were sought in the medial midbrain, whereas lens accommodation of the eye was monitored by using an infrared high-speed optometer. Nineteen of 135 units isolated were identified as accommodation-related units by two criteria: 1) they discharged in synchrony with spontaneously occurring accommodation, and b) the units were driven by stimulating the interpositus nucleus of the cerebellum. In eight other experiments, units were sought that were antidromically activated by stimulating parasympathetic preganglionic fibers to the ciliary ganglion. Eleven of 46 antidromically activated units were identified as accommodation-related units (accommodation-related oculomotor units). Accommodation-related oculomotor units were found in the medial midbrain within 1 mm of the midline. The majority of them were located lateral and dorsal to the Edinger-Westphal nucleus. more...
- Published
- 1984
35. Specificity of the newly-formed corticorubral synapses in the kitten red nucleus
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Y. Fujito, Nakaakira Tsukahara, and M. Kubota
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Cerebellum ,Red nucleus ,Pyramidal Tracts ,Biology ,Synaptic Transmission ,Kitten ,Interneurons ,biology.animal ,Reaction Time ,medicine ,Animals ,Dominance, Cerebral ,Evoked Potentials ,Red Nucleus ,Cerebral Cortex ,Brain Mapping ,Pyramidal tracts ,General Neuroscience ,Cerebral peduncle ,Neural Inhibition ,Dendrites ,Somatosensory Cortex ,Anatomy ,Electric Stimulation ,Nerve Regeneration ,medicine.anatomical_structure ,Cerebellar Nuclei ,Cerebral cortex ,Synapses ,Cats ,Excitatory postsynaptic potential ,Forelimb ,Neuroscience - Abstract
We have examined the formation of new synapses that occurs in the kitten red nucleus (RN) following lesions of the cerebral cortex or cerebellum. In normal 2–3 month old kittens, stimulation of the cerebral cortex or cerebral peduncle (CP) produces slow-rising monosynaptic EPSPs in ipsilateral RN cells; while fast-rising EPSPs are produced by stimulating the contralateral nucleus interpositus (IP) of the cerebellum. In these normal animals stimulation of the contralateral cerebral cortex, or CP, or the ipsilateral IP never produces detectable postsynaptic potentials. In contrast, in kittens with chronic lesions of the ipsilateral sensorimotor cortex performed less than 2 months after birth, it was found that (1) stimulation of the contralateral sensorimotor cortex or CP produced slow-rising EPSPs. (2) Upon stimulation of the contralateral IP a slow-rising component appeared superimposed on the fast-rising IP-EPSPs. (3) In some cells, stimulation of the ipsilateral IP produced slow-rising EPSPs. These results indicate that new synapses were formed on the dendrites of RN cells by neurons from the contralateral CP, contralateral IP and ipsilateral IP. The majority of denervated RN neurons were found to receive new synapses from only one of these three inputs, those from the contralateral cerebral cortex being most prominent. The conduction velocities of corticorubral fibers responsible for the EPSPs recorded in these lesioned animals are similar to those of slow conducting pyramidal tract fibers. Sometimes IPSPs were also produced by a train of CP stimuli. The IPSPs are probably mediated by fast conducting pyramidal tract fibers because their threshold is lower than that of the EPSPs. These findings suggest that newly formed crossed corticorubral projections have organizational specificity with respect to excitatory vs. inhibitory connections which is similar to that of normal ipsilateral corticorubral projections. Somatotopical organization was found in the newly-formed corticorubral excitatory projections. The forelimb cortical area was found to project to contralateral RN neurons innervating the forelimb spinal segments, while the hindlimb cortical area was found to project to RN neurons innervating the lumbar segments. However, after chronic ablation of the forelimb area of the contralateral sensorimotor cortex, in addition to the ipsilateral cerebral cortex, a new connection was formed from the hindlimb area of the contralateral cerebral cortex to the RN neurons innervating the spinal forelimb segments. This indicates that the specificity of the topographical organization is subject to reorganization. In chronically hemicerebellectomized kittens, ipsilateral IP stimulation produced fast-rising monosynaptic EPSPs in some cases. Thus, it was concluded that new synapses were formed on the somatic or proximal dendritic portion of RN cells from the ipsilateral IP after ablation of the contralateral IP. more...
- Published
- 1983
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36. GABAergic intrinsic interneurons in the red nucleus of the cat demonstrated with combined immunocytochemistry and anterograde degeneration methods
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Nakaakira Tsukahara, Hironobu Katsumaru, Fujio Murakami, and Jang-Yen Wu
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Red nucleus ,Glutamate decarboxylase ,Biology ,Neurotransmission ,Synaptic Transmission ,gamma-Aminobutyric acid ,Interneurons ,medicine ,Methods ,Animals ,Axon ,gamma-Aminobutyric Acid ,Red Nucleus ,Neurons ,Histocytochemistry ,General Neuroscience ,Immunochemistry ,Motor Cortex ,Neural Inhibition ,General Medicine ,Somatosensory Cortex ,medicine.anatomical_structure ,nervous system ,Nerve Degeneration ,Cats ,GABAergic ,Neuroscience ,Nucleus ,medicine.drug ,Motor cortex - Abstract
The presence of glutamic acid decarboxylase (GAD), the enzyme synthesizing gamma-aminobutyric acid (GABA), was investigated in the red nucleus by an immunocytochemical method. The ipsilateral sensorimotor cortex was ablated prior to the immunocytochemical procedures to examine whether cortical neurons make synaptic contacts with GAD-immunoreactive neurons. Small GAD-immunoreactive neurons with a major diameter of 16.1 +/- 3.2 micron (mean +/- S.D.) were observed in the red nucleus under both light and electron microscopy. They were uniformly distributed throughout the nucleus. Degenerating axon terminals were found making synaptic contact with GAD-immunoreactive neurons in the red nucleus, which suggests that there is an input from the ipsilateral sensorimotor cortex to these neurons. This observation, along with our previous findings that GABAergic axon terminals make synaptic contact with the rubrospinal neurons, provides anatomical evidence for the presence of intrinsic GABAergic interneurons which mediate cortical inhibition in cat rubrospinal neurons. more...
- Published
- 1984
37. A new algorithm for voltage clamp by iteration: a learning control of a nonlinear neuronal system
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Mitsuo Kawato, Nakaakira Tsukahara, Manabu Etoh, and Yoichi Oda
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Engineering ,Time Factors ,General Computer Science ,Voltage clamp ,Computation ,Models, Neurological ,Stability (learning theory) ,Neural Conduction ,Membrane Potentials ,Control theory ,Waveform ,Animals ,Electronic circuit ,Neurons ,business.industry ,Decapodiformes ,Electric Conductivity ,Feedback loop ,Axons ,Electric Stimulation ,Cell Compartmentation ,Nonlinear system ,business ,Algorithm ,Mathematics ,Biotechnology ,Voltage - Abstract
Voltage-clamp of excitable membrane allows the measurement of membrane currents associated with electrical potential changes across the membrane. However, it has been impossible in practice to apply the conventional analog feedback voltage-clamp circuits to single electrode voltage clamping in central neurons. The reason for this is that the feedback system becomes unstable because of the positive feedback required for compensation of capacitative loss through the wall of the microelectrode. Park et al. (1981) proposed a new iterative technique to solve this problem. It requires that the potential to be clamped repeats itself with little or no change. The amount of current needed to clamp the membrane potential is not determined at once, but in a step-wise, trial and error fashion in the course of a set of repetitions. Since the feedback loop is open in real time, the system has great stability, and this advantage can be exploited in single electrode preparations. The computation algorithm which calculates the current waveform based on the voltage deviation during the last trial is the central part of the iterative voltage-clamp system. In this paper, we propose a new algorithm, which has several theoretical and practical advantages over the original one proposed by Park et al. First, two parameters used in the new algorithm are predetermined by a current-clamp experiment. Second, the speed of convergence of the new algorithm is faster than that of the Park's original algorithm. This was shown by computer simulation of iterative voltage clamp of artificial membrane following Hodgkin-Huxley equations for squid axon membrane and Rall's compartment model for a neuron with dendrites. Finally, we offer proof that the new algorithm is certain to converge for the general cases of voltage-clamp experiments with active membrane properties, synaptic membranes, etc. Consequently, the new algorithm for iterative voltage clamp is very suitable for single electrode voltage clamp in the central neurons. The new algorithm has been successfully applied to voltage-clamp experiments on rubrospinal neurons of cats (Tsukahara, Murakami, Kawato, Oda, and Etoh, in preparation). more...
- Published
- 1985
38. Classical Conditioning Mediated by the Red Nucleus in the Cat
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Nakaakira Tsukahara
- Published
- 1982
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39. Theoretical study on electrical properties of dendritic spines
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Mitsuo Kawato and Nakaakira Tsukahara
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musculoskeletal diseases ,Statistics and Probability ,Dendritic spine ,Models, Neurological ,Dendrite ,Biology ,General Biochemistry, Genetics and Molecular Biology ,Membrane Potentials ,Synapse ,Postsynaptic potential ,medicine ,Animals ,Humans ,Membrane potential ,General Immunology and Microbiology ,Applied Mathematics ,Electric Conductivity ,General Medicine ,Anatomy ,Dendrites ,musculoskeletal system ,Dendritic filopodia ,Spine (zoology) ,medicine.anatomical_structure ,Modeling and Simulation ,Synapses ,Functional significance ,General Agricultural and Biological Sciences ,Neuroscience - Abstract
In most parts of mammalian central nervous system the majority of synapses are located on dendritic spines. Several suggestions have been made about the functional significance of the dendritic spines. We investigate electrical properties of dendritic spines in the neurons with arbitrary dendritic geometry. Following Butz & Cowan (1974), all dendritic branches, including spines, are treated as cylinders of uniform passive membrane. We show that the postsynaptic potential due to the synapse on the spine is represented as a convolution integral of the following two functions. The first is the postsynaptic potential caused by the same synapse on the branching point where the spine stalk is attached to the main dendritic trunk. The second function is determined mainly by the morphological and electrical properties of the spine and it represents the attenuation effect of the spine. On the assumption that the diameter of the spine stalk is sufficiently small compared to that of the parent dendrite to which the spine stem is attached, we obtain an approximation of the second function and conclude that morphological change of the spine does not produce an effective change of the postsynaptic potential, hence does not provide the neural basis for learning or memory simply by changing cable properties of dendrites. Moreover, we show that synapses on the dendritic spine are not effectively isolated from other synapses on the same assumption. more...
- Published
- 1983
40. The cerebellar control of accommodation of the eye in the cat
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Nakaakira Tsukahara, Minoru Hosoba, and Takehiko Bando
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Cerebellum ,genetic structures ,Stimulation ,Visual system ,Refraction, Ocular ,Brain mapping ,Cerebellar Cortex ,Lens, Crystalline ,medicine ,Reaction Time ,Animals ,Visual Pathways ,Molecular Biology ,Dioptre ,Brain Mapping ,business.industry ,Adaptation, Ocular ,General Neuroscience ,Accommodation, Ocular ,Neural Inhibition ,Electric Stimulation ,medicine.anatomical_structure ,nervous system ,Cerebellar Nuclei ,Lens (anatomy) ,Cerebellar cortex ,Cats ,Neurology (clinical) ,business ,Neuroscience ,Nucleus ,Developmental Biology - Abstract
The effect of cerebellar stimulation on the accommodation of the lens was examined in anesthetized cats. An infrared optometer was used to measure the refractive power of the lens during stimulation of the cerebellum. The area giving responses within latencies shorter than 160 msec and amplitudes larger than 0.15 diopters is localized in the contralateral interpositus and fastigial nuclei and the ipsilateral interpositus nucleus. No responses could be evoked by stimulating the bilateral lateral nuclei. Accommodation responses were also evoked by cerebellar cortex stimulation. Accommodation responses evoked by stimulating the cerebellar nuclei were inhibited by preceding cerebellar cortical stimulation. more...
- Published
- 1978
41. Formation of functional synapses in the adult cat red nucleus from the cerebrum following cross-innervation of forelimb flexor and extensor nerves
- Author
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Y. Fujito, M. Yoshida, Yoichi Oda, and Nakaakira Tsukahara
- Subjects
CATS ,Red nucleus ,Cerebrum ,Chemistry ,General Neuroscience ,Brain ,Anatomy ,Cross innervation ,Peripheral ,Spinal Nerves ,medicine.anatomical_structure ,Forelimb ,Synapses ,Time course ,Cats ,medicine ,Animals ,Red Nucleus ,Sprouting - Abstract
The effects of cross-innervation of peripheral flexor and extensor nerves on the time course and properties of red nucleus (RN) neurons were studied in adult cats. The time course of corticorubral unitary EPSPs was examined. In operated cats, RN neurons innervating upper spinal segments (C-cells) manifested corticorubral unitary EPSPs with shorter time-to-peak and larger amplitude than in normal cats. The mean amplitude of these EPSPs was 0.41 +/- 0.11 mV; the mean time-to-peak was 1.14 +/- 0.51 ms (n = 18). These values differ from normal cats (0.33 +/- 0.09 mV, and 2.68 +/- 0.61 ms, n = 22). RN neuron membrane properties were examined in cross-innervated cats. The main time constant was 5.2 +/- 0.7 ms (n = 10), the shorter equalizing time constant, 0.69 +/- 0.19 ms (n = 10), the input resistance, 2.5 +/- 0.8 M omega. These values were not significantly different from those of normal cats. The electrotonic length was 1.2 (n = 10), somewhat larger than in normal cats. The number of converging interpositorubral synapses, estimated in eight cells from cross-innervated cats, ranged from 37 to 57. This was not significantly different from normal cats, and indicated that there is no large-scale degeneration of interpositorubral synapses after cross-innervation. These results suggest that sprouting and formation of functional synapses occur after cross-innervation of peripheral flexor and extensor nerves. more...
- Published
- 1982
- Full Text
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42. Cortical neurons related to lens accommodation in posterior lateral suprasylvian area in cats
- Author
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Nobuhiko Yamamoto, Nakaakira Tsukahara, and Takehiko Bando
- Subjects
Superior Colliculi ,Physiology ,Thalamus ,Biology ,Midbrain ,Lens, Crystalline ,medicine ,Animals ,Visual Pathways ,Pretectal area ,Evoked Potentials ,Cerebral Cortex ,Brain Mapping ,General Neuroscience ,Superior colliculus ,Accommodation, Ocular ,Anatomy ,Sulcus ,Electric Stimulation ,Antidromic ,medicine.anatomical_structure ,Cerebellar Nuclei ,Cerebral cortex ,Lens (anatomy) ,Thalamic Nuclei ,Cats ,Neuroscience - Abstract
Cortical units were sought that discharged in temporal correlation with spontaneously occurring lens accommodation in the area surrounding the middle suprasylvian sulcus, between the stereotaxic coordinates A8.0 and P1.0, while monitoring lens accommodation by using an infrared optometer. Units were tentatively identified as accommodation related if their discharges were modulated before the onset times of lens accommodation. Forty-eight accommodation-related units were found. Modulation of discharges preceded the onset times of accommodation by 360 ms on the average. Most (95%) of these units were related to the increase in the refractive power of the lens. Antidromic activation from the dorsal midbrain was tested in 26 of 48 accommodation-related units. Fourteen (67%) units were antidromically activated from the superior colliculus and/or the pretectum. Nine (64%) of them were also activated antidromically from the lateral posterior nucleus of the thalamus. The location of these units were confirmed by histological reconstruction. They were found in the posterior medial and posterior lateral lateral suprasylvian (PMLS and PLLS) areas and in the transitional zone of PMLS to the suprasylvian gyrus, between stereotaxic coordinates A7.0 and A1.5. more...
- Published
- 1984
43. Properties of the synaptic transmission of the newly formed cortico-rubral synapses after lesion of the nucleus interpositus of the cerebellum
- Author
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Y. Fujito, Fujio Murakami, and Nakaakira Tsukahara
- Subjects
Recruitment, Neurophysiological ,Cerebellum ,Time Factors ,Red nucleus ,Neurotransmission ,Synaptic Transmission ,medicine ,Animals ,Evoked Potentials ,Red Nucleus ,Cerebral Cortex ,CATS ,Chemistry ,musculoskeletal, neural, and ocular physiology ,General Neuroscience ,Cerebral peduncle ,Long-term potentiation ,Anatomy ,Denervation ,Electric Stimulation ,Nerve Regeneration ,medicine.anatomical_structure ,nervous system ,Cerebellar Nuclei ,Synapses ,Cats ,Tetanic stimulation ,Neuroscience ,Nucleus - Abstract
1. Properties of synaptic transmission during and after repetitive activation of the newly formed cortico-rubral synapses were examined in the red nucleus neurons (RN) of cats after lesions of the nucleus interpositus of the cerebellum (chronic cats) as well as in normal ones. 2. A prominent facilitation of the amplitude of cortico-rubral unitary EPSPs was observed in both normal and chronic cats when a stimulus to the cerebral peduncle (CP) was preceded by another stimulus by 2–50 msec. 3. Time course of the facilitation shows that it attains maximum at the interval of about 3 msec and decays approximately exponentially lasting for 50 msec or more. 4. When three successive stimuli of identical intensity were applied to CP, the degree of facilitation was more prominent than that for double shock. 5. There was a positive correlation between the time to peak of the cortico-rubral EPSPs and their maximum value of facilitation. 6. The posttetanic potentiation of the cortico-rubral EPSPs was observed after tetanic stimulation to CP in chronic and normal cats. It lasts for a few minutes in both cases. more...
- Published
- 1977
44. Calcium-dependent potentials in mammalian red nucleus neurons in vitro
- Author
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Nakaakira Tsukahara, Michinori Kubota, and Makoto Nakamura
- Subjects
Red nucleus ,Guinea Pigs ,Action Potentials ,Tetrodotoxin ,In Vitro Techniques ,Guinea pig ,chemistry.chemical_compound ,Extracellular ,Animals ,Red Nucleus ,Manganese ,Tetraethylammonium ,General Neuroscience ,Conductance ,Depolarization ,General Medicine ,Cobalt ,Tetraethylammonium Compounds ,Slow afterhyperpolarization ,chemistry ,Biophysics ,Potassium ,Calcium ,Neuroscience ,Intracellular - Abstract
Intracellular recordings were made from red nucleus (RN) neurons in guinea-pig slice preparations. The slow afterhyperpolarization (AHP) following an action potential was reversibly abolished by Co2+ or Mn2+. Its amplitude was dependent on the extracellular K+ concentration. When tetraethylammonium was added to the perfusing solution, a tetrodotoxin-resistant regenerative depolarization was evoked which was blocked by Co2+ or Mn2+. There results suggest that the slow AHP is produced by an increase in Ca2+-dependent K+ conductance and that RN neurons have a voltage-dependent Ca2+ conductance. more...
- Published
- 1984
45. SYNAPTIC PLASTICITY IN THE RED NUCLEUS
- Author
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Nakaakira Tsukahara
- Subjects
Synaptic fatigue ,Synaptic scaling ,nervous system ,Postsynaptic potential ,musculoskeletal, neural, and ocular physiology ,Synaptic augmentation ,Synaptic plasticity ,Metaplasticity ,Medial lemniscus ,Nonsynaptic plasticity ,Biology ,Neuroscience - Abstract
Publisher Summary The morphological discovery that synaptic reorganization takes place after the partial deafferentation of septal nucleus in adult rats indicates that the neuronal connection in the mammalian central nervous system is not as rigid as has long been considered. Red nucleus (RN) represents a suitable preparation to determine whether new, functionally effective synaptic connections are formed. Cortico-rubral fibers terminate on the distal dendrites and fibers from the contralateral nucleus interpositus (IP) of the cerebellum make synaptic contact on the soma. The cortico-rubral dendritic EPSPs are characterized with slow-rising time course, whereas the somatic IP-excitatory postsynaptic potentials (EPSPs) are characterized with fast-rising time course. EPSPs from medial lemniscus have rise time between those of IP-rubral and cortico-rubral EPSPs. Sprouting and synaptic reorganization are not limited to the cases of removal of the direct synaptic inputs of RN neurons. A major goal of the study of neuronal plasticity is to provide a neuronal basis for behavioral plasticity, such as learning and memory. These studies range from the examination of simple behavioral phenomena to classical conditioning phenomena. more...
- Published
- 1981
- Full Text
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46. Formation of functional synapses in the adult cat red nucleus from the cerebrum following cross-innervation of forelimb flexor and extensor nerves
- Author
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Jun Maeda, Yoichi Oda, Nakaakira Tsukahara, and Y. Fujito
- Subjects
Red nucleus ,Population ,Biology ,Forelimb ,medicine ,Animals ,education ,Evoked Potentials ,Red Nucleus ,education.field_of_study ,CATS ,Cerebrum ,General Neuroscience ,Cerebral peduncle ,Brain ,Anatomy ,Membrane hyperpolarization ,Axons ,Electric Stimulation ,Antidromic ,Spinal Nerves ,medicine.anatomical_structure ,Spinal Cord ,Nerve Degeneration ,Synapses ,Cats - Abstract
We investigated the effects of cross-innervating the peripheral forelimb flexor and extensor nerves of adult cats on the time course of corticorubral EPSPs. Red nucleus neurons were identified by antidromic invasion from C1 or L1 spinal segments as innervating the upper spinal segments (C-cells) or sending axons to the lumbosacral cord (L-cells). In C-cells, a fast-rising component, superimposed on the slow-rising corticorubral EPSPs induced by the cerebral sensorimotor cortex or the cerebral peduncle (CP) stimulation, was noted. The mean time-to-peak of this component in cross-innervated cats operated more than two months earlier was 1.9 +/- 0.9 ms (n = 160), shorter than in normal cats (3.6 +/- 1.4 ms, n = 100). The same value in cats cross-innervated less than two months before was 2.7 +/- 1.0 ms (n = 53). The mean time-to-peak of CP-EPSPs from L-cells was 2.9 +/- 0.9 ms (n = 115). The fast-rising component had a latency of 0.96 +/- 0.19 ms (n = 122), and it was mediated by fibers with conduction velocities of less than 20 m/s. The projective area of the fast-rising component is organized somatotopically. Since it is more sensitive to membrane hyperpolarization than slow rising corticorubral EPSPs, it is mediated by synapses located more proximally than the corticorubral synapses of normal cats. The time course of facilitation by preceding cerebral peduncle stimulation of the nucleus interpositus (IP)-induced RN population responses was measured. It was characterized by a rapid, followed by a slower, rise time in the RN region where C-cells are concentrated. In contrast, the L-cell region was characterized by a slow rise time. In cats subjected to self-union of the peripheral flexor and extensor nerves, the majority of C-cells had CP-EPSPs with a time-to-peak within the normal range. Our results suggest that after cross-innervation sprouting and formation of functional synapses occur on the proximal portion of the soma-dendritic membrane of red nucleus neurons. more...
- Published
- 1982
- Full Text
- View/download PDF
47. Synaptic currents at interpositorubral and corticorubral excitatory synapses measured by a new iterative single-electrode voltage-clamp method
- Author
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Mitsuo Kawato, Fujio Murakami, Yoichi Oda, Manabu Etoh, and Nakaakira Tsukahara
- Subjects
Synaptic potential ,Cerebral Cortex ,General Neuroscience ,Voltage clamp ,Neural facilitation ,Neural Conduction ,Neural Inhibition ,General Medicine ,Biology ,Neurotransmission ,Synaptic Transmission ,Membrane Potentials ,Electrophysiology ,Cerebellar Nuclei ,Synaptic augmentation ,Synaptic plasticity ,Neural Pathways ,Synapses ,Excitatory postsynaptic potential ,Cats ,Animals ,Neuroscience ,Red Nucleus - Abstract
A new iterative single-electrode voltage clamp method was applied to the measurement of synaptic currents in the red nucleus (RN) neuron of the cat. Voltage clamp was attained within 10 repetitions with great stability and the new algorithm was demonstrated to be superior to the original algorithm of iterative voltage clamp. With a conventional microelectrode, it was possible to measure the synaptic current with the time resolution of 50 microseconds. The synaptic currents evoked by stimulation of the contralateral interpositus nucleus (IP) had time-to-peak ranging from 200 to 540 microseconds and fitted well to alpha functions. Corticorubral (CR) synaptic current was also measured by making use of synaptic plasticity. The stimulation of the ipsilateral cerebral peduncle in cats with chronic lesion of the contralateral IP evoked fast rising EPSPs, as reported previously. The CR-EPSPs with times-to-peak less than 1 ms were subjected to voltage clamp. The CR synaptic currents had times-to-peak ranging from 350 to 880 microseconds. Since most of the interpositorubral (IR) synapses and a part of the CR synapses in IP-lesioned cats are situated on the somatic membrane of RN neurons and some of the CR synaptic currents were as rapid as the IR synaptic currents, the observed synaptic currents evoked by stimulation of the IP and those of the fast-rising CR-EPSPs were taken to originate from the synaptic membrane under space-clamp, i.e. soma. The present study provided additional evidence for the sprouting of the CR fibers as well as the time course of the synaptic current at the dendritic synapses remote from the soma, for the first time. more...
- Published
- 1986
48. A quantitative study of synaptic reorganization in red nucleus neurons after lesion of the nucleus interpositus of the cat: an electron microscopic study involving intracellular injection of horseradish peroxidase
- Author
-
Fujio Murakami, Kitihiro Saito, Hironobu Katsumaru, and Nakaakira Tsukahara
- Subjects
Pathology ,medicine.medical_specialty ,Red nucleus ,Somatosensory system ,Horseradish peroxidase ,Lesion ,Neural Pathways ,medicine ,Animals ,Regeneration ,Molecular Biology ,Red Nucleus ,CATS ,Neuronal Plasticity ,biology ,Chemistry ,General Neuroscience ,Motor Cortex ,Anatomy ,Somatosensory Cortex ,Electrophysiology ,Microscopy, Electron ,medicine.anatomical_structure ,Synapses ,biology.protein ,Cats ,Neurology (clinical) ,medicine.symptom ,Nucleus ,Developmental Biology ,Motor cortex - Abstract
A quantitative electron microscopic analysis of the corticorubral projection was performed in the red nucleus (RN) of adult cats to determine morphological correlates of synaptic reorganization that occur following a lesion of the interpositus nucleus (IP). Corticorubral synaptic endings were identified by lesioning the sensorimotor cortex 2-6 days before electrophysiological experiments. Horseradish peroxidase (HRP) was injected into electrophysiologically identified RN neurons. Sagittal sections 100 micrometers thick were cut and reacted by diaminobenzidine. Sections containing HRP-positive neurons were selected and embedded in Epon. In normal cats, degenerating corticorubral terminals in the RN region frequently made contact with dendritic profiles, having small cross-sections, while a few made contact with somatic profiles. Similar results were obtained when degenerating terminals making contact with HRP-filled dendrites were analyzed. In the experimental animals, the cortical lesion was performed more than 8 weeks after lesion of the IP. In these animals, degenerating corticorubral terminals were frequently found on proximal dendrites and somata in RN region and HRP-positive neurons in contrast to the findings in normal cats. The results indicate that new corticorubral synapses were formed on proximal dendrites and somata of RN neurons as a consequence of IP lesions. more...
- Published
- 1982
49. Synaptic plasticity in the red nucleus and learning
- Author
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Yoichi Oda, Fujio Murakami, and Nakaakira Tsukahara
- Subjects
Cerebral Cortex ,Neuronal Plasticity ,Chemistry ,Red nucleus ,Conditioning, Classical ,Classical conditioning ,Stimulus (physiology) ,Nerve Regeneration ,Synapse ,Behavioral Neuroscience ,medicine.anatomical_structure ,Synaptic plasticity ,Neuroplasticity ,Neural Pathways ,Synapses ,medicine ,Excitatory postsynaptic potential ,Cats ,Animals ,Soma ,Neuroscience ,Red Nucleus - Abstract
Pairing of the stimulus to the cerebral peduncle (CP) with that to the forearm skin leads cats to flex their forearms within a 10-day training period in response to stimulus to CP, which was initially ineffective. Behavioral study and extracellular unit analysis suggested that the cellular mechanism for this conditioning lies at the corticorubral (CR) synapses. Since formation of new CR synapses occurs in parallel with the recovery from behavioral deficits after brain damage and peripheral nerve cross-innervation, we explored the possibility that the formation of new CR synapses underlies conditioning. We investigated the time course of the CR excitatory postsynaptic potentials (EPSPs) as well as the distribution of the CR synapses on the somadendritic membrane of the red nucleus neurons and compared them with those observed in control animals. In conditioned animals, the times-to-peak of the CR EPSPs were significantly shorter than those in control animals. Electron microscopic studies demonstrated that more CR synapses make contact with large, i.e. proximal, dendrites and somata of red nucleus neurons in conditioned cats than in control ones. These results support the view that the formation of new synapses on the proximal dendrites and soma underlies classical conditioning in the cat. more...
- Published
- 1988
50. Cortical neurons in and around the Clare-Bishop area related with lens accommodation in the cat
- Author
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Kenji Tsukuda, Nobuhiko Yamamoto, Nakaakira Tsukahara, Jun Maeda, and Takehiko Bando
- Subjects
Cerebral Cortex ,Neurons ,Cerebellum ,business.industry ,General Neuroscience ,Accommodation, Ocular ,Cortical neurons ,Anatomy ,Biology ,medicine.anatomical_structure ,Superior cerebellar peduncle ,Lens (anatomy) ,Lens, Crystalline ,medicine ,Cats ,Animals ,Evoked Potentials, Visual ,Neurology (clinical) ,business ,Molecular Biology ,Accommodation ,Neuroscience ,Developmental Biology ,Visual Cortex - Abstract
Single-unit discharges in the cat Clare-Bishop area were correlated with spontaneous accommodation responses. No appreciable change was found in accommodation responses evoked by stimulating the Clare-Bishop area, when cerebellar outflow was blocked reversibly by cooling the superior cerebellar peduncle. It is suggested, therefore, that the Clare-Bishop area plays an important role in the lens accommodation system through a pathway independent from that of the cerebellum. more...
- Published
- 1981
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