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The aim of this study was to perform a comparative investigation of white matter integrity in patients with prelingual and postlingual deafness; we carried out a tract-based statistical analysis of diffusion tensor anisotropy in eight and ten adults with prelingual and postlingual deafness, respectively. Patients with deafness showed significant decreases in diffusion anisotropy at the right internal capsule, the right thalamus, and the splenium of the corpus callosum as well as within the bilateral superior temporal gyrus (including Heschl gyrus) and right temporal white matter. Furthermore, relative to patients with postlingual deafness, those with prelingual deafness showed lower anisotropy in the right superior temporal gyrus, bilateral temporal white matter, and the genu and anterior body of the corpus callosum. We believe that, in patients with deafness, reception of early auditory stimuli before language acquisition might be more critical to white matter maturation and brain reorganization than the nature of auditory stimuli itself or the duration of disuse. These findings provide the theoretical background for early auditory rehabilitation.

Abstract: Most leading research in basic and clinical neuroscience has been carried out by functional magnetic resonance imaging (fMRI), which detects the blood oxygenation level dependent signals associated with neural activities. Among new fMRI applications, brain decoding is an emerging research area, which infers mental states from fMRI signals. Brain decoding using fMRI includes classification, identification, and reconstruction of brain states. It is generally conducted using multi-voxel pattern analysis based on neuroscientific evidence that brain functions are mediated by distributed activation patterns. Brain decoding techniques have been successful in diverse applications such as the brain computer interface, patient monitoring, and neurofeedback. These techniques have expanded our understanding of how the brain encodes distinct information. In the current paper, we reviewed recent fMRI-based brain decoding techniques and applications. We also discussed the potential implications of brain decoding in neuroscience.

To investigate neuroanatomical correlates of the categorization of laryngeally contrastive phonemes, an event-related functional magnetic resonance imaging was performed during an auditory identification task in which 10 participants were distinguished among the three types of word-initial stop phonemes, either lax, tense, or aspirated. Perception of the aspirated consonant series elicited significantly higher activation in the inferior frontal gyrus as compared with both the lax and tense series, and the tense series showed significantly higher activation in the left superior temporal gyrus in comparison with either the lax or the aspirated series. The results show differential involvement of frontal and temporal lobe language areas for distinct phonemic contrasts, supporting a linguistic feature formulation model that posits variably specified phonological representations for the three-way distinctions.

To explore the effects of white matter in the absence of auditory input in the early deaf, we conducted a tract-based statistical analysis of the diffusion tensor anisotropy and the voxel-based morphometry in the white matter of 13 early deaf and 29 hearing individuals. Deaf individuals showed significant decreases in diffusion anisotropy and in regional volume reductions within the temporal white matter. Decreased anisotropy was also found at the internal capsule, superior longitudinal fasciculus, and the inferior frontal white matter. In contrast, the forceps major of the corpus callosum, where interhemispheric connections between visual cortices exist, showed increased anisotropy. We interpreted these white matter alterations in terms of both disuse-driven atrophy and compensatory plasticity in the early deaf.

We examined whether deficient prefrontal control over the semantic network exists in patients with schizophrenia. Fourteen patients with schizophrenia and 14 healthy controls performed a comparison task, judging semantic congruity according to an abstract category in an event-related functional MRI paradigm. In the control group, prefrontal–temporal networks consisting of the left inferior frontal gyrus and right inferior frontal sulcus converging at the left posterior superior temporal sulcus were identified as activated during semantic demand of incongruence. In the patients with schizophrenia, we observed a loss of the recruitment of the right inferior frontal sulcus and the prefrontal–temporal network. These findings indicate that cognitive modulation of semantic processing may be dysfunctional in patients with schizophrenia.

Diffusion properties of the thalamocortical pathways were compared between 30 schizophrenic patients and 22 healthy age-matched and sex-matched volunteers. T1-weighted and diffusion tensor images were used for cortical parcellation and probabilistic tractography to generate population-based thalamocortical pathway maps. The weighted fractional anisotropy and the longitudinal and transversal diffusivity of each pathway were calculated for individual participants. Patients with schizophrenia demonstrated decreased anisotropy and increased longitudinal and transversal diffusivity within the pathways from the mediodorsal nucleus and the pulvinar to the orbitofrontal and parietal-occipital-temporal lobes. Anisotropy decreases and diffusivity increases were correlated with positive and negative syndrome scale scores. Alterations in global diffusion properties within the thalamocortical pathways imply the disruption of brain circuitry in schizophrenic patients.

Critical times of involvement of areas important to working memory were examined both with pitch and audioverbal N-back tasks using single-pulse transcranial magnetic stimulation (TMS). TMS was administered to 12 healthy participants over dorsolateral prefrontal and inferior parietal regions in each hemisphere at four different times after stimulus onset (250, 450, 650, and 850 ms). For the pitch N-back task, interference with working memory, as evidenced by a significant increase in reaction time, was observed with TMS over the right hemisphere regions. In contrast, for the audioverbal N-back task, TMS resulted in significantly increased reaction time only for left inferior parietal TMS delivered 450 ms after stimulus onset. These results imply different hemispheric specializations for pitch and audioverbal working memory.

The neural reorganization of the visual cortex of early blind individuals was evaluated using voxel-by-voxel analysis of diffusion tensor images with regard to the diffusion direction, diffusion anisotropy and diffusivity. Reduced anisotropy and increased diffusivity was found mainly in the visual pathways of 18 early blind individuals as opposed to 25 sighted individuals. Alteration of the diffusion direction was detected not only in the visual pathways but also in nonvisual pathways such as the u fibers of the parietal lobe, the sagittal striatum, the pulvinar and the inferior and superior longitudinal fasciculi. The alteration of regional diffusion direction, reduced anisotropy and increased diffusivity in early blind individuals imply the neural reorganization for functional adaptation to the loss of visual input during the early development period.

Patients with schizophrenia exhibit deficits in semantic processing, which can form the basis of thought disorders. The objective of this study was to explore functional connectivity between the activated areas during semantic processing in schizophrenia. Twelve patients with schizophrenia and 12 healthy controls were studied with 15OH2O positron-emission tomography during semantic judgment. The expected activation in the left inferior occipitotemporal cortex significantly correlated with several other regional activations in normal study participants, but with no other regional activations in patients with schizophrenia. This finding suggests that schizophrenia involves a disconnection of semantic networks. The resultant distortion in semantic processing may have an impact on thought disorders.

The goal of this study was to test the feasibility of visualizing a 3-dimensional structure of cerebral white matter fiber tracts in preterm infants, postconceptional age (PCA) 28 weeks to term, by using volumetric diffusion tensor magnetic resonance imaging (DTI) data.

The purpose of this study is to evaluate the difference between anatomical locations of mismatch negativity (MMN) generators using a realistic head model and the Talairach coordinate system. This was performed by dipole source analysis by using a high density 128 channel electroencephalography (EEG) acquisition system and the subjects' individual 3D magnetic resonance images (MRI) for the realistic head model, in 24 healthy subjects. For dipole source localization, both the Talairach coordinate system and the individual MRI realistic head models were used and location results were compared. The MMN generators were clearly localized in the superior temporal gyri, especially in Heschl's gyrus, according to each individual's structural MRI. Only 37.5% of subjects showed the same anatomical locations of the MMN generator in both hemispheres in the realistic head model and in Talairach coordinate system, but fifteen subjects (62.5%) didn't. This result indicates that individually registered functional locations are desirable for the precise localization of activated areas in functional imaging studies and that a brain coordinate system is needed which adequately accounts for ethnic differences.

We describe a method for the statistical parametric mapping of low resolution electromagnetic tomography (LORETA) using high‐density electroencephalography (EEG) and individual magnetic resonance images (MRI) to investigate the characteristics of the mismatch negativity (MMN) generators in schizophrenia. LORETA, using a realistic head model of the boundary element method derived from the individual anatomy, estimated the current density maps from the scalp topography of the 128‐channel EEG. From the current density maps that covered the whole cortical gray matter (up to 20,000 points), volumetric current density images were reconstructed. Intensity normalization of the smoothed current density images was used to reduce the confounding effect of subject specific global activity. After transforming each image into a standard stereotaxic space, we carried out statistical parametric mapping of the normalized current density images. We applied this method to the source localization of MMN in schizophrenia. The MMN generators, produced by a deviant tone of 1,200 Hz (5% of 1,600 trials) under the standard tone of 1,000 Hz, 80 dB binaural stimuli with 300 msec of inter‐stimulus interval, were measured in 14 right‐handed schizophrenic subjects and 14 age‐, gender‐, and handedness‐matched controls. We found that the schizophrenic group exhibited significant current density reductions of MMN in the left superior temporal gyrus and the left inferior parietal gyrus (P< 0. 0005). This study is the first voxel‐by‐voxel statistical mapping of current density using individual MRI and high‐density EEG. Hum. Brain Mapping 17:168–178, 2002. © 2002 Wiley‐Liss, Inc.

Mismatch Negativity (MMN) reflects a neural mismatch between an incoming stimuli and the transient representation of stimuli in short-term memory. MMN mechanism forms the basis of unattended change detection, which may lead to the switching of involuntary attention. We used high resolution EEG and LORETA images to investigate the changes of MMN sources over time. Individual structural MRI was used for realistic head modeling and each electrode position in 3-D space was digitized. The right frontal area was activated later than the temporo-parietal generator. The temporo-parieto-frontal network is responsible for template updating and an involuntary attention switch to changes in the auditory environment.

We investigated the effect of aqueous extract of Perilla frutescens(Labiatae) (PFAE) on the mast cell-mediated immediate-type allergic reactions. PFAE(0.05 to 1 g/kg) dose-dependently inhibited systemic allergic reaction induced by compound 48/80 in rats. PFAE(0.1 and 1 g/kg) also significantly inhibited local allergic reaction activated by anti-DNP IgE. When PFAE was pretreated at the same concentrations with systemic allergic reaction test, the plasma histamine levels were reduced in a dose-dependent manner. PFAE(10-3 to 1 mg/ml) dose-dependently inhibited the histamine release from rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. The level of cyclic AMP in RPMC, When PFAE(1 mg/ml) was added, transiently and significantly increased about 4-fold compared with that of basal cells. Moreover, PFAE(0.001 and 0.01 mg/ml) had a significant inhibitory effect on anti-DNP IgE-induced tumor necrosis factor-α production. These results indicate that PFAE inhibits mast cell-mediated immediate-type allergic reactions in vivo and in vitro.

Estrogen and estrogen receptors (ERs) are known to play important roles in the pathophysiology of osteoarthritis (OA). To investigate ER-α gene polymorphisms for its associations with primary knee OA, we conducted a case–control association study in patients with primary knee OA (n = 151) and healthy individuals (n = 397) in the Korean population. Haplotyping analysis was used to determine the relationship between three polymorphisms in the ER-α gene (intron 1 T/C, intron 1 A/G and exon 8 G/A) and primary knee OA. Genotypes of the ER-α gene polymorphism were determined by PCR followed by restriction enzyme digestion (PvuII for intron 1 T/C, XbaI for intron 1 A/G, and BtgI for exon 8 G/A polymorphism). There was no significant difference between primary knee OA patients and healthy control individuals in the distribution of any of the genotypes evaluated. However, we found that the allele frequency for the exon 8 G/A BtgI polymorphism (codon 594) was significantly different between primary knee OA patients and control individuals (odds ratio = 1.38, 95% confidence interval = 1.01–1.88; P = 0.044). In haplotype frequency estimation analysis, there was a significant difference between primary knee OA patients and control individuals (degrees of freedom = 7, χ2 = 21.48; P = 0.003). Although the number OA patients studied is small, the present study shows that ER-α gene haplotype may be associated with primary knee OA, and genetic variations in the ER-α gene may be involved in OA.

Estrogen and estrogen receptors (ERs) are known to play important roles in the pathophysiology of osteoarthritis (OA). To investigate ER-α gene polymorphisms for its associations with primary knee OA, we conducted a case–control association study in patients with primary knee OA (n= 151) and healthy individuals (n= 397) in the Korean population. Haplotyping analysis was used to determine the relationship between three polymorphisms in the ER-α gene (intron 1 T/C, intron 1 A/G and exon 8 G/A) and primary knee OA. Genotypes of the ER-α gene polymorphism were determined by PCR followed by restriction enzyme digestion (PvuII for intron 1 T/C, XbaI for intron 1 A/G, and BtgI for exon 8 G/A polymorphism). There was no significant difference between primary knee OA patients and healthy control individuals in the distribution of any of the genotypes evaluated. However, we found that the allele frequency for the exon 8 G/A BtgI polymorphism (codon 594) was significantly different between primary knee OA patients and control individuals (odds ratio = 1.38, 95% confidence interval = 1.01–1.88; P =0.044). In haplotype frequency estimation analysis, there was a significant difference between primary knee OA patients and control individuals (degrees of freedom = 7, χ2= 21.48; P= 0.003). Although the number OA patients studied is small, the present study shows that ER-α gene haplotype may be associated with primary knee OA, and genetic variations in the ER-α gene may be involved in OA.