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Natural vestibular and optokinetic stimulation were used to investigate the possible role of the cerebellar nodulus in the regulation and modification of reflexive eye movements in rabbits. The nodulus and folium 9d of the uvula were destroyed by surgical aspiration. Before and after nodulectomy the vertical and horizontal vestibuloocular reflexes (VVOR, HVOR) were measured during sinusoidal vestibular stimulation about the longitudinal (roll) and vertical (yaw) axes. Although the gain of the HVOR (GHVOR= peak eye movement velocity/peak head velocity) was not affected by the nodulectomy, the gain of the VVOR (GVVOR) was reduced. The gains of the vertical and horizontal optokinetic reflexes (GVOKR, GHOKR) were measured during monocular, sinusoidal optokinetic stimulation (OKS) about the longitudinal and vertical axes. Following nodulectomy, there was no reduction in GVOKRor GHOKR. Long-term binocular OKS was used to generate optokinetic afternystagmus, OKAN II, that lasts for hours. After OKAN II was induced, rabbits were subjected to static pitch and roll, to determine how the plane and velocity of OKAN II is influenced by a changing vestibular environment. During static pitch, OKAN II slow phase remained aligned with earth-horizontal. This was true for normal and nodulectomized rabbits. During static roll, OKAN II remained aligned with earth-horizontal in normal rabbits. During static roll in nodulectomized rabbits, OKAN II slow phase developed a centripetal vertical drift. We examined the suppression and recovery of GVVORfollowing exposure to conflicting vertical OKS for 10–30 min. This vestibular-optokinetic conflict reduced GVVORin both normal and nodulectomized rabbits. The time course of recovery of GVVORafter conflicting OKS was the same before and after nodulectomy. In normal rabbits, the head pitch angle, at which peak OKAN II velocity occurred, corresponded to the head pitch angle maintained during long-term OKS. If the head was maintained in a “pitched-up” or “pitched-down” orientation during long-term OKS, the subsequently measured OKAN II peak velocity occurred at the same orientation. This was not true for nodulectomized rabbits, who had OKAN II peak velocities at head pitch angles independent of those maintained during long-term OKS. We conclude that the nodulus participates in the regulation of compensatory reflexive movements. The nodulus also influences “remembered” head position in space derived from previous optokinetic and vestibular stimulation.

Abstract: A patient with stage III vulvar squamous cell carcinoma who was successfully treated with intra-arterial and intravenous chemotherapy and subsequent local excision is presented. The tumor was located on the left side of the vulva. Chemotherapy initially was administered into the left internal iliac artery. After two courses of the intra-arterial infusions, the tumor was no longer visible macroscopically. Two additional courses of chemotherapy were given intravenously to treat possible metastases to the lymph nodes. After the chemotherapy, the tumor site in the vulva was excised. A few small nests of tumor cells were identified in the excised specimen. The appearance of the vulva after surgery was quite natural and similar to that of a woman without disease. The patient is alive and disease-free 36 months after surgery. Conservative therapy, which includes intra-arterial and intravenous chemotherapy, should be considered for selected women with advanced vulvar squamous cell carcinoma.

1. The complex spike (CS) of the floccular Purkinje cell has been reported to be driven by retinal image movement in the rabbit, the rat, and the monkey, but not yet in the cat, in which the floccular neuronal network is well known. We recorded the CS activity together with concomitant simple spike (SS) activity of the floccular Purkinje cells that responded to large-field visual pattern movement in the anesthetized cat. 2. On the basis of the direction selectivity we divided the cells into two major types: the horizontal type that preferred horizontal stimuli and the vertical type that preferred vertical stimuli. The CS activity of the horizontal-type cell increased during stimuli directed contralaterally to the recording site and decreased during ipsilaterally directed stimuli, whereas that of the vertical-type cell increased during upward stimuli and decreased during downward stimuli. 3. In both types the CS response was larger at lower-velocity stimuli and the response was well maintained at higher-velocity stimuli < or = 180 degrees/s tested. The mean response decline was only 50% at stimulus velocities 90-150 degrees/s compared with the response amplitude at 2 degrees/s stimulus velocity. 4. The majority of the horizontal-type cells were modulated by the stimuli presented to either eye and the dominant eye was ipsilateral to the recording site. The majority of the vertical-type cells were also modulated by the stimuli presented to either eye without obvious differences between two eyes. 5. In both types the receptive field of the ipsilateral eye always included the area centralis and extended widely on both visual hemifields. The receptive field of the contralateral eye also included the area centralis and was usually restricted within the ipsilateral visual hemifield. The stimuli of small visual field (15 degrees x 15 degrees) projecting to the area centralis evoked especially large responses (70% of the full-screen response). 6. The CS and SS responses were reciprocal to each other, that is, when the CS firing increased the SS firing decreased and vice versa. 7. These CS responses are well suited for the direction detection of large-field retinal image motion at a wide velocity range. In light of the present unitary spike data together with the anatomic and eye movement data reported previously, we conclude that the cat flocculus is responsible for reduction of the large-field retinal image motion by producing eye movement in the same direction with the visual motion.

1. There are two opposite points of view concerning the way climbing fiber input in a Purkinje cell modifies simple spike (SS) activity transiently: depression versus enhancement of SS activity. The different groups of investigators favored one effect predominating over the other. In the decerebrate unanesthetized cat, we recorded spontaneous activity of single Purkinje cells and investigated time course of SS activity after the complex spike (CS). 2. In the peri-CS time histogram, there was a SS pause lasting, on average, 10.8 ms after onset of the CS in all of the 316 cells recorded. The pause was followed by a rapid increase in SS activity to a maximum, which was on average 175.6% of a pre-CS control level, and a gradual return to around the control level in the majority of the cells recorded (pause-facilitation type, 71.2%). The increase in SS activity was significant (P < 0.01, t test) during 20-100 ms. The SS activity during the 20-100 ms was, on average, 163.7% of the control level. In some cells (pure-pause type, 25.3%), no significant changes were found (P > 0.01) in the post-pause SS firing. In contrast, only 3.5% of the cells (pause-reduction type) showed a significant (P < 0.01) firing decrease (average 54.0% of the control level) lasting 20-60 ms after the pause period. 3. Analysis of the pre-CS time histogram revealed no significant differences (P > 0.01) in the SS activity between pre-CS periods in all of the cells recorded, suggesting that the SS activity enhancement is not due to a coactivated mossy fiber input just preceding the activation of the climbing fiber input. 4. Analysis of the raster diagram revealed variability of individual SS responses after the CS. The probability of occurrence of the increase in SS number during a post-CS period of 0-100 ms with respect to that during a pre-CS period of -100-0 ms in individual raster traces was high (on average 78.2%), medium (57.3%), and low (36.3%) in the pause-facilitation, pure-pause, and pause-reduction types of the cell, respectively. 5. Nonsequential time histograms showing frequency distribution of the pause duration after the CS in individual raster traces and that showing interspike intervals of the SS were constructed.(ABSTRACT TRUNCATED AT 400 WORDS)

1. Some scientists reported that the simple spike (SS) activity was transiently depressed after climbing fiber input, but others reported that predominant population of Purkinje cells increased their SS activity after the complex spike (CS). In the present study, SS activity after spontaneous CS was compared before and after the administration of pentobarbital sodium and of ketamine in high decerebrate cats. 2. Frequencies of spontaneous CS and SS firing were reduced (P < 0.001, t test) after pentobarbital administration of a total dose of 20-30 mg/kg. 3. In the peri-CS time histogram, the SS activity during a post-CS period of 10-110 ms with respect to that during a pre-CS period of -100-0 ms was reduced (P < 0.001) after the pentobarbital administration from, on average, 132.4 to 81.9%. In contrast, the SS activity during a post-CS period of 110-210 ms remained unchanged (P > 0.2). 4. In the pre-CS time histogram constructed after the pentobarbital administration, there were no significant differences (P > 0.01) between the SS activity during a pre-CS period of -600 to -500 ms and that during each of other pre-CS periods, suggesting that the barbiturate had little effect on the SS activity preceding the CS. 5. Analysis of raster diagrams revealed the variability of individual SS activity after the CS.(ABSTRACT TRUNCATED AT 250 WORDS)

1. In the anesthetized decorticate cat, we recorded complex spike (CS) activity together with concomitant simple spike (SS) activity of the cerebellar flocculus (FL) Purkinje cells that responded to large-field visual pattern movement. The cerebral cortical contributions to the visual response characteristics were investigated by comparing the present results with the previous results of the anesthetized normal cat. 2. The direction-selective characteristics of the CS responses at a low (2 degrees/s) stimulus velocity are well preserved after the decortication. As in the normal cat, the cells are divided into two major types: the horizontal type that prefers horizontal stimuli and the vertical type that prefers vertical stimuli. The CS rate of the former increases during stimuli directed contralaterally to the recording site and decreases during ipsiversive stimuli, whereas that of the latter increases during upward stimuli and decreases during downward stimuli. Reciprocal properties of the CS and SS responses also are preserved: when the CS rate increases, the SS rate decreases and vice versa. 3. For both types, the CS modulation at high stimulus velocities is reduced after the decortication. The half-reduction of the average modulation occurs at approximately 100 degrees/s stimulus velocity compared with the modulation at 2 degrees/s in the normal cat, whereas it occurs at a lower velocity approximately 50 degrees/s in the decorticate cat. 4. For both types, the CS responses usually are driven through either eye in the normal cat. After the decortication, the CS modulation through the contralateral eye is reduced. 5. For both types, the receptive field of the ipsilateral eye extends into both visual hemifields in the normal cat. The CS responses through the contralateral visual hemifield are abolished, whereas those through the ipsilateral visual hemifield are preserved after the decortication. The CS modulation during stimuli restricted within a small central visual field (15 degrees x 15 degrees) projecting to the area centralis is prominent (approximately 70% of the full-screen response) in the normal cat and is sharply reduced (30%) after the decortication.(ABSTRACT TRUNCATED AT 400 WORDS)

Fushiki, H. and N. H. Barmack.Topography and reciprocal activity of cerebellar Purkinje cells in the uvula-nodulus modulated by vestibular stimulation. J. Neurophysiol.78: 3083–3094, 1997. In the rabbit uvula-nodulus, vestibular and optokinetic information is mapped onto parasagittal zones by climbing fibers. These zones are related functionally to different pairs of vertical semicircular canals, otolithic inputs and horizontal optokinetic inputs. Vestibular stimulation restricted to one of these zones modulates climbing fiber responses (CFRs). Within each of these zones, simple spikes (SSs) are modulated reciprocally with CFRs. In rabbits anesthetized with chloralose-urethan, we have used vestibular and optokinetic stimulation to evoke CFRs within a parasagittal zone while recording from Purkinje cells in adjacent zones. We have examined whether the CFRs evoked by vestibular stimulation in one zone influence the SSs of an adjacent zone. CFRs and SSs were recorded during roll vestibular stimulation. The orientation of the head of the rabbit with respect to the axis of rotation was varied systematically so that a climbing fiber null plane could be determined. This null plane was the orientation of the head about the vertical axis at which no modulation of the CFR was observed during rotation about the longitudinal axis of the vestibular rate table. In the left uvula-nodulus, a medial sagittal strip extending through all the folia contained Purkinje cells with CFRs that had optimal planes of stimulation coplanar with the left posterior-right anterior semicircular canals (LPC-RAC). Lateral to this strip was a strip of Purkinje cells with CFRs that were characterized by optimal planes corresponding to stimulation of the left anterior-right posterior semicircular canals (LAC-RPC). SSs in Purkinje cells were modulated out of phase with CFRs from the same Purkinje cell. The depth of modulation of both CFRs and SSs was reduced during rotation in the climbing fiber “null plane”. The depth of modulation of SSs was greatest when recorded from Purkinje cells located at the center of semicircular canal-related strip. We observed that 1) all folia of the uvula-nodulus receive vestibular climbing fiber inputs; 2) these climbing fiber inputs convey information from the vertical semicircular canals and otoliths but not the horizontal semicircular canals; 3) CFRs evoked in a particular sagittal zone do not influence SSs in adjacent zones; 4) modulation of a CFRs in a particular Purkinje cell can occur without modulation of SSs in the same Purkinje cell, although modulation of SSs was not observed in the absence of CFR modulation; and 5) modulation of SSs sometimes preceded that of CFRs in the same cell, implying that interneuronal pathways may contribute to SS modulation. Climbing fiber-driven Golgi cells, the inhibitory axon terminals of which end on granule cell dendrites in the classic glomerular synapse, may provide this interneuronal mechanism.