Impaired white matter connectivity between regions containing mirror neurons,and relationship to negative symptoms and social cognition,in patients with first-episode schizophrenia

In schizophrenia, abnormalities in structural connectivity between brain regions known to contain mirror neurons and their relationship to negative symptoms related to a domain of social cognition are not well understood. Diffusion tensor imaging (DTI) scans were acquired in 16 patients with first episode schizophrenia and 16 matched healthy controls. FA and Trace of the tracts interconnecting regions known to be rich in mirror neurons, i.e., anterior cingulate cortex (ACC), inferior parietal lobe (IPL) and premotor cortex (PMC) were evaluated. A significant group effect for Trace was observed in IPL-PMC white matter fiber tract (F (1, 28) = 7.13, p = .012), as well as in the PMC-ACC white matter fiber tract (F (1, 28) = 4.64, p = .040). There were no group differences in FA. In addition, patients with schizophrenia showed a significant positive correlation between the Trace of the left IPL-PMC white matter fiber tract, and the Ability to Feel Intimacy and Closeness score (rho = .57, p = 0.034), and a negative correlation between the Trace of the left PMC-ACC and the Relationships with Friends and Peers score (rho = remove -.54, p = 0.049). We have demonstrated disrupted white mater microstructure within the white matter tracts subserving brain regions containing mirror neurons. We further showed that such structural disruptions might impact negative symptoms and, more specifically, contribute to the inability to feel intimacy (a measure conceptually related to theory of mind) in first episode schizophrenia. Further studies are needed to understand the potential of our results for diagnosis, prognosis and therapeutic interventions.     

The topological organization of white matter network in internet gaming disorder individuals

White matter (WM) integrity abnormalities had been reported in Internet gaming disorder (IGD). Diffusion tensor imaging (DTI) tractography allows identification of WM tracts, potentially providing information about the integrity and organization of relevant underlying WM fiber tracts’ architectures, which has been used to investigate the connectivity of cortical and subcortical structures in several brain disorders. Unfortunately, relatively little is known about the thoroughly circuit-level characterization of topological property changes of WM network with IGD. Sixteen right-hand adolescents with IGD participated in our study, according to the diagnostic criteria of IGD in DSM-5. Meanwhile, 16 age and gender-matched healthy controls were also enrolled. DTI tractography was employed to generate brain WM networks in IGD individuals and healthy controls. The 90 cortical and subcortical regions derived from AAL template were chosen as the nodes. The network parameters (i.e., Network strength, clustering coefficient, shortest path length, global efficiency, local efficiency, regional efficiency) were calculated and then correlated with the Internet addiction test (IAT) scores in IGD. IGD group showed decreased global efficiency, local efficiency and increased shortest path length. Further analysis revealed the reduced nodal efficiency in frontal cortex, anterior cingulate cortex and pallidium in IGD. In addition, the global efficiency of WM network was correlated with the IAT scores in IGD (r = ?0.5927; p = 0.0155). We reported the abnormal topological organization of WM network in IGD and the association with the severity of IGD, which may provide new insights into the neural mechanism of IGD from WM network level.     

Patterns of cortical thinning in idiopathic rapid eye movement sleep behavior disorder

Idiopathic rapid eye movement sleep behavior disorder is a parasomnia that is a risk factor for dementia with Lewy bodies and Parkinson's disease. Brain function impairments have been identified in this disorder, mainly in the frontal and posterior cortical regions. However, the anatomical support for these dysfunctions remains poorly understood. We investigated gray matter thickness, gray matter volume, and white matter integrity in patients with idiopathic rapid eye movement sleep behavior disorder. Twenty‐four patients with polysomnography‐confirmed idiopathic rapid eye movement sleep behavior disorder and 42 healthy individuals underwent a 3‐tesla structural and diffusion magnetic resonance imaging examination using corticometry, voxel‐based morphometry, and diffusion tensor imaging. In the patients with idiopathic rapid eye movement sleep behavior disorder, decreased cortical thickness was observed in the frontal cortex, the lingual gyrus, and the fusiform gyrus. Gray matter volume was reduced in the superior frontal sulcus only. Patients showed no increased gray matter thickness or volume. Diffusion tensor imaging analyses revealed no significant white matter differences between groups. Using corticometry in patients with idiopathic rapid eye movement sleep behavior disorder, several new cortical regions with gray matter alterations were identified, similar to those reported in dementia with Lewy bodies and Parkinson's disease. These findings provide some anatomical support for previously identified brain function impairments in this disorder. © 2014 International Parkinson and Movement Disorder Society     

Changes in brain white matter integrity after systemic treatment for breast cancer: a prospective longitudinal study

An increasing number of studies suggest chemotherapy for breast cancer may be neurotoxic. Cross-sectional MRI diffusion tensor imaging (DTI) studies suggest a vulnerability of brain white matter to various chemotherapeutic regimens. Up till now, this was confirmed in one prospective DTI study: Deprez et al. (2012) showed a widespread decline in fractional anisotropy (FA) of breast cancer patients after chemotherapy consisting of 5-fluorouracil (5-FU), epirubicin and cyclophosphamide (FEC) +/? taxanes +/? endocrine treatment. Our aim was to evaluate whether similar detrimental effects on white matter integrity would be observed with the currently widely prescribed anthracycline-based chemotherapy for breast cancer (predominantly doxorubicin and cyclophosphamide +/? taxanes +/? endocrine treatment (=BC + SYST; n = 26) compared to no systemic treatment (BC; n = 23) and no-cancer controls (NC; n = 30). Assessment took place before and six months after chemotherapy, and matched intervals for the unexposed groups. DTI data were analyzed using voxel-based tract-based spatial statistics and region of interest (ROI) analysis. Voxel-based analysis did not show an effect of chemotherapy +/? endocrine treatment on white matter integrity. ROI analysis however indicated subtle detrimental effects of chemotherapy +/? endocrine treatment by showing a larger decline in WM integrity in the superior longitudinal fasciculus and corticospinal tract in BC + SYST than BC. Indications for relatively mild neurotoxicity in our study might be explained by patient characteristics and specific aspects of data analysis. The omission of 5-FU in current treatment regimens or the administration of doxorubicin instead of epirubicin is also discussed as an explanation for the observed effects.     

Anomalous gray matter structural networks in recent onset post-traumatic stress disorder

Alterations of the topological organization of abnormal regions or network-level structural aberrations are still poorly understood for post-traumatic stress disorder (PTSD). Herein, we investigated brain structural networks in recent-onset PTSD patients, all affected by the coalmine-flood disaster. Cortical networks were studied in recent onset PTSD patients (n = 15) and matched healthy controls (n = 25). Cortical networks were constructed by thresholding correlation matrices of 150 regions and quantified using graph theoretical approaches. Contributions of high-degree nodes, and regional and global network measures, including degree and betweenness, were studied. Compared with healthy controls, PTSD patients showed altered quantitative values in global network properties, characterized by shorter path length and higher clustering. Moreover, PTSD patients exhibited decreased connectivity in the right lingual gyrus, parahippocampal gyrus, left supramarginal gyrus, parahippocampal gyrus, bilateral superior and inferior frontal gyrus, superior frontal gyrus, and posterior cingulate gyrus. Nodal centrality decreased predominantly in the occipital regions (lingual gyrus) and default-mode regions, while increased correlations and centralities were observed in the medial temporal lobe and posterior cingulate cortex. PTSD-related networks exhibited a less efficient organization and regional connectivity. According to these findings, we conclude that regional connections involving fear-processing and re-experiential-processing cortex may play a role in maintaining or adapting to PTSD pathology.     

Is depression a disconnection syndrome? Meta-analysis of diffusion tensor imaging studies in patients with MDD

Background: Many studies using diffusion tensor imaging (DTI) have demonstrated impaired white matter integrity in patients with major depressive disorder (MDD), with significant results found in diverse brain regions. We sought to identify whether there are consistent changes of regional white matter integrity in patients with MDD, as shown by decreased fractional anisotropy in DTI. Method: A systematic search strategy was used to identify relevant whole brain voxel-based DTI studies of patients with MDD in relation to comparison groups. Relevant databases were searched for studies published between January 1994 and February 2011 using combinations of the terms "DTI" or "diffusion tensor;" "whole brain" or "voxel-based;" and "depress*." Using the studies that met our inclusion criteria, we performed a meta-analysis of the coordinates of decreased fractional anisotropy using the activation likelihood estimation (ALE) method, which detects 3-dimensional conjunctions of coordinates from multiple studies, weighted by sample size. We then used DTIquery software for fibre tracking to locate the fascicles involved in each region. Results: We included 11 studies with a combined sample of 231 patients with MDD and 261 comparison participants, providing 50 coordinates of decreased fractional anisotropy. Our meta-analysis identified 4 consistent locations of decreased fractional anisotropy in patients with MDD: white matter in the right frontal lobe, right fusiform gyrus, left frontal lobe and right occipital lobe. Fibre tracking showed that the main fascicles involved were the right inferior longitudinal fasciculus, right inferior fronto-occipital fasciculus, right posterior thalamic radiation and interhemispheric fibres running through the genu and body of the corpus callosum. Limitations: The number of studies included was relatively small, and the DTI data acquisition and analysis techniques were heterogeneous. The ALE method cannot handle studies with no significant group differences. Conclusion: Voxel-based analysis of DTI studies of patients with MDD consistently identified decreased fractional anisotropy in the white matter fascicles connecting the prefrontal cortex within cortical (frontal, temporal and occipital lobes) and subcortical areas (amygdala and hippocampus). This isstrong evidence for the involvement of these neural circuits in the pathology of MDD.     

White matter abnormalities in first-episode, treatment-naive young adults with major depressive disorder

OBJECTIVE: The aim of this study was to explore the microstructural integrity of whole-brain white matter by diffusion tensor imaging in first-episode, treatment-naive young adults with major depressive disorder. METHOD: Diffusion tensor imaging scans were obtained from 14 first-episode, treatment-naive young adult patients with major depressive disorder and 14 healthy comparison subjects. A voxel-based method was used to analyze the scans. RESULTS: The patient group exhibited significantly lower fractional anisotropy values than healthy comparison subjects in the white matter of the right middle frontal gyrus, the left lateral occipitotemporal gyrus, and the subgyral and angular gyri of the right parietal lobe. There were no regions of significantly higher fractional anisotropy values in patients compared with healthy comparison subjects. CONCLUSIONS: These findings suggest that abnormalities of brain white matter may be present early in the course of major depressive disorder. They also support the idea that white matter lesions may disrupt the neural circuits involved in mood regulation and thus contribute to the neuropathology of major depressive disorder.     

White matter microstructure of patients with neurofibromatosis type 1 and its relation to inhibitory control

Neurofibromatosis Type 1 (NF1) is commonly associated with deficits in executive functions such as working memory and inhibitory control. A valid biomarker to describe the pathological basis of these deficits in NF1 is not available. The aim of this study was to investigate whether any abnormalities in white matter integrity of the executive function related anterior thalamic radiation (ATR), cingulate bundle (CB), and superior longitudinal fasciculus (SLF) may be regarded as a pathological basis for inhibitory control deficits in adolescents with NF1. Sixteen NF1 patients and 32 healthy controls underwent 3 T DTI MRI scanning. Whole brain-, ATR-, CB-, and SLF-white matter integrity were studied using fractional anisotropy, mean (MD), radial, and axial (DA) diffusivity. Correlation analyses between white matter metrics and inhibitory control (as measured with a computerized task) were performed. Also, verbal and performance abilities (IQ-estimates) were assessed and correlated with white matter metrics. Patients showed significant whole brain- and local microstructural pathology when compared to healthy controls in all measures. In NF1-patients, whole-brain (MD: r = .646 and DA: r = .673) and ATR- (r-range: ?.405–.771), but not the CB- (r-range: ?.307–.472) and SLF- (r-range: ?.187–.406) white matter integrity, were correlated with inhibitory control. Verbal and performance abilities were not associated with white matter pathology. In NF1, white matter abnormalities are observed throughout the brain, but damage to the ATR seems specifically, or at least most strongly related to inhibitory control. Future studies should examine whether reduced white matter integrity in other brain regions or tracts is (more strongly) associated with different aspects of the cognitive-behavioral phenotype associated with NF1.     

Abnormalities of white matter integrity in the corpus callosum of adolescents with PTSD after childhood sexual abuse: a DTI study

This study seeks to determine whether white matter integrity in the brain differs between adolescents with post-traumatic stress disorder (PTSD) due to childhood sexual abuse (CSA) and matched healthy adolescents and whether there is a relationship between white matter integrity and symptom severity in the patient group. Using 3T diffusion tensor imaging, we examined fractional anisotropy (FA) in a group of adolescents with CSA-related PTSD (n = 20) and matched healthy controls (n = 20), in a region of interest consisting of the bilateral uncinate fasciculus (UF), the genu, splenium and body of the corpus callosum (CC), and the bilateral cingulum. In addition, we performed an exploratory whole brain analysis. Trauma symptomatology was measured with the Trauma Symptom Checklist for Children (TSCC) to enable correlational analyses between FA differences and trauma symptomatology. The PTSD group had significantly lower FA values in the genu, midbody and splenium of the CC in comparison with controls (p < 0.05, tfce corrected). Post hoc analyses of the eigenvalues of the DTI scan showed increased radial and mean diffusivity in the patient group. In addition, we found a significant negative correlation between scores on the anger subscale of the TSCC and FA values in the left body of the CC in patients (p < 0.05). Adolescents with CSA-related PTSD show decreased FA in the CC, with abnormalities in the integrity of the left body of the CC being related to anger symptoms. These findings suggest that early trauma exposure affects the development of the CC, which may play a role in the pathophysiology of PTSD in adolescents.     

Relevance of neuroimaging for neurocognitive and behavioral outcome after pediatric traumatic brain injury

This study aims to (1) investigate the neuropathology of mild to severe pediatric TBI and (2) elucidate the predictive value of conventional and innovative neuroimaging for functional outcome. Children aged 8–14 years with trauma control (TC) injury (n = 27) were compared to children with mild TBI and risk factors for complicated TBI (mild^RF+, n = 20) or moderate/severe TBI (n = 17) at 2.8 years post-injury. Neuroimaging measures included: acute computed tomography (CT), volumetric analysis on post-acute conventional T1-weighted magnetic resonance imaging (MRI) and post-acute diffusion tensor imaging (DTI, analyzed using tract-based spatial statistics and voxel-wise regression). Functional outcome was measured using Common Data Elements for neurocognitive and behavioral functioning. The results show that intracranial pathology on acute CT-scans was more prevalent after moderate/severe TBI (65%) than after mild^RF+ TBI (35%; p = .035), while both groups had decreased white matter volume on conventional MRI (ps ≤ .029, ds ≥ ?0.74). The moderate/severe TBI group further showed decreased fractional anisotropy (FA) in a widespread cluster affecting all white matter tracts, in which regional associations with neurocognitive functioning were observed (FSIQ, Digit Span and RAVLT Encoding) that consistently involved the corpus callosum. FA had superior predictive value for functional outcome (i.e. intelligence, attention and working memory, encoding in verbal memory and internalizing problems) relative to acute CT-scanning (i.e. internalizing problems) and conventional MRI (no predictive value). We conclude that children with mild^RF+ TBI and moderate/severe TBI are at risk of persistent white matter abnormality. Furthermore, DTI has superior predictive value for neurocognitive out-come relative to conventional neuroimaging.     

Anterior cingulate, gyrus rectus, and orbitofrontal abnormalities in elderly depressed patients: an MRI-based parcellation of the prefrontal cortex

OBJECTIVE: To examine structural abnormalities in subregions of the prefrontal cortex in elderly patients with depression, the authors explored differences in gray matter, white matter, and CSF volumes by applying a parcellation method based on magnetic resonance imaging (MRI). METHOD: Twenty-four elderly patients with major depression and 19 group-matched comparison subjects were studied with high-resolution MRI. Cortical surface extraction, tissue segmentation, and cortical parcellation methods were applied to obtain volume measures of gray matter, white matter, and CSF in seven prefrontal subregions: the anterior cingulate, gyrus rectus, orbitofrontal cortex, precentral gyrus, superior frontal cortex, middle frontal cortex, and inferior frontal cortex. RESULTS: Highly significant bilateral volume reductions in gray matter were observed in the anterior cingulate, the gyrus rectus, and the orbitofrontal cortex. Depressed patients also exhibited significant bilateral white matter volume reductions and significant CSF volume increases in the anterior cingulate and the gyrus rectus. Finally, the depressed group showed significant CSF volume reductions in the orbitofrontal cortex relative to the comparison subjects. None of the other regions examined revealed significant structural abnormalities. CONCLUSIONS: The prominent bilateral gray matter deficits in the anterior cingulate and the gyrus rectus as well as the orbitofrontal cortex may reflect disease-specific modifications of elderly depression. The differential pattern of abnormalities detected in the white matter and CSF compartments imply that distinct etiopathological mechanisms might underlie the structural cortical changes in these regions.     

Microstructural development: Organizational differences of the fiber architecture between children and adults in dorsal and ventral visual streams

Visual perceptual skills are basically mature by the age of 7 years. White matter, however, continues to develop until late adolescence. Here, we examined children (aged 5–7 years) and adults (aged 20–30 years) using diffusion tensor imaging (DTI) fiber tracking to investigate the microstructural maturation of the visual system. We characterized the brain volumes, DTI indices, and architecture of visual fiber tracts passing through white matter structures adjacent to occipital and parietal cortex (dorsal stream), and to occipital and temporal cortex (ventral stream). Dorsal, but not ventral visual stream pathways were found to increase in volume during maturation. DTI indices revealed expected maturational differences, manifested as decreased mean and radial diffusivities and increased fractional anisotropy in both streams. Additionally, fractional anisotropy was increased and radial diffusivity was decreased in the adult dorsal stream, which can be explained by specific dorsal stream myelination or increasing fiber compaction. Adult dorsal stream architecture showed additional intra‐ and interhemispheric connections: Dorsal fibers penetrated into contralateral hemispheres via commissural structures and projection fibers extended to the superior temporal gyrus and ventral association pathways. Moreover, intra‐hemispheric connectivity was particularly strong in adult dorsal stream of the right hemisphere. Ventral stream architecture also differed between adults and children. Adults revealed additional connections to posterior lateral areas (occipital‐temporal gyrus), whereas children showed connections to posterior medial areas (posterior parahippocampal and lingual gyrus). Hence, in addition to dorsal stream myelination or fiber compaction, progressing maturation of intra‐ and interhemispheric connectivity may contribute to the development of the visual system. Hum Brain Mapp, 2011. © 2010 Wiley‐Liss, Inc.     

抑郁症患者脑白质变化初步研究

目的：利用能够提示脑白质纤维完整性的磁共振弥散张量成像（DTI）探讨首发和复发重性抑郁症患者脑白质纤维的变化及其差异。方法：20例重性抑郁症患者（首发9例，复发11例）和20名正常对照者均经常规磁共振成像（MRI）平扫，未发现异常者继续进行DTI和结构MRI（3D）扫描，基于像素的全脑分析技术对DTI数据进行分析。结果：与对照组相比较，抑郁症组白质纤维结构在双侧额中回、右顶下小叶及双侧脑岛等区域白质的各向异性值（FA）显著降低（各脑区P均〈0.001，cluster〉30像素）;与首发抑郁症患者相比较，复发抑郁症患者右侧额上回、右顶叶、中央前回、中央后回及右顶下小叶等区域FA值降低更为显著（各脑区P均〈0.001，cluster〉10像素）。结论：重性抑郁症患者存在脑白质异常，抑郁反复发作会导致脑白质损害进一步加重。     

Cortical thickness development of human primary visual cortex related to the age of blindness onset

Blindness primarily induces structural alteration in the primary visual cortex (V1). Some studies have found that the early blind subjects had a thicker V1 compared to sighted controls, whereas late blind subjects showed no significant differences in the V1. This implies that the age of blindness onset may exert significant effects on the development of cortical thickness of the V1. However, no previous research used a trajectory of the age of blindness onset-related changes to investigate these effects. Here we explored this issue by mapping the cortical thickness trajectory of the V1 against the age of blindness onset using data from 99 blind individuals whose age of blindness onset ranged from birth to 34 years. We found that the cortical thickness of the V1 could be fitted well with a quadratic curve in both the left (F = 11.59, P = 3 × 10^?5) and right hemispheres (F = 6.54, P = 2 × 10^?3). Specifically, the cortical thickness of the V1 thinned rapidly during childhood and adolescence and did not change significantly thereafter. This trend was not observed in the primary auditory cortex (A1), primary motor cortex (M1), or primary somatosensory cortex (S1). These results provide evidence that an onset of blindness before adulthood significantly affects the cortical thickness of the V1 and suggest a critical period for cortical development of the human V1.     

Cerebellar Neural Circuits Involving Executive Control Network Predict Response to Group Cognitive Behavior Therapy in Social Anxiety Disorder

Some intrinsic connectivity networks including the default mode network (DMN) and executive control network (ECN) may underlie social anxiety disorder (SAD). Although the cerebellum has been implicated in the pathophysiology of SAD and several networks relevant to higher-order cognition, it remains unknown whether cerebellar areas involved in DMN and ECN exhibit altered resting-state functional connectivity (rsFC) with cortical networks in SAD. Forty-six patients with SAD and 64 healthy controls (HC) were included and submitted to the baseline resting-state functional magnetic resonance imaging (fMRI). Seventeen SAD patients who completed post-treatment clinical assessments were included after group cognitive behavior therapy (CBT). RsFC of three cerebellar subregions in both groups was assessed respectively in a voxel-wise way, and these rsFC maps were compared by two-sample t tests between groups. Whole-brain voxel-wise regression was performed to examine whether cerebellar connectivity networks can predict response to CBT. Lower rsFC circuits of cerebellar subregions compared with HC at baseline (p < 0.05, corrected by false discovery rate) were revealed. The left Crus I rsFC with dorsal medial prefrontal cortex was negatively correlated with symptom severity. The clinical assessments in SAD patients were significantly decreased after CBT. Higher pretreatment cerebellar rsFC with angular gyrus and dorsal lateral frontal cortex corresponded with greater symptom improvement following CBT. Cerebellar rsFC circuits involving DMN and ECN are possible neuropathologic mechanisms of SAD. Stronger pretreatment cerebellar rsFC circuits involving ECN suggest potential neural markers to predict CBT response.     

Voxel-based analysis of MRI detects abnormal visual cortex in children and adults with amblyopia

Amblyopia, sometimes called "lazy eye," is a relatively common developmental visual disorder well characterized behaviorally; however, the neural substrates associated with amblyopia in humans remain unclear. We hypothesized that abnormalities in the cerebral cortex of subjects with amblyopia exist, possibly as a result of experience-dependent neuronal plasticity. Anatomic magnetic resonance imaging (MRI) and psychophysical vision testing was carried out on 74 subjects divided into two age ranges, 7-12 years and 18-35 years, and three diagnoses, strabismic amblyopia, anisometropic amblyopia, and normal vision. We report a behavioral impairment in contrast sensitivity for subjects with amblyopia, consistent with previous reports. When the high-resolution MRI brain images were analyzed quantitatively with optimized voxel-based morphometry, results indicated that adults and children with amblyopia have decreased gray matter volume in visual cortical regions, including the calcarine sulcus, known to contain primary visual cortex. This finding was confirmed with a separate region-of-interest analysis. For the children with amblyopia, additional gray matter reductions in parietal-occipital areas and ventral temporal cortex were detected, consistent with recent reports that amblyopia can result in spatial location and object processing deficits. These data are the first to provide possible neuroanatomic bases for the loss of binocularity and visual sensitivity in children and adults with amblyopia.     

Cortical thickness abnormalities in trichotillomania: international multi-site analysis

Trichotillomania is a prevalent but often hidden psychiatric condition, characterized by repetitive hair pulling. The aim of this study was to confirm or refute structural brain abnormalities in trichotillomania by pooling all available global data. De-identified MRI scans were pooled by contacting authors of previous studies. Cortical thickness and sub-cortical volumes were compared between patients and controls. Patients (n = 76) and controls (n = 41) were well-matched in terms of demographic characteristics. Trichotillomania patients showed excess cortical thickness in a cluster maximal at right inferior frontal gyrus, unrelated to symptom severity. No significant sub-cortical volume differences were detected in the regions of interest. Morphometric changes in the right inferior frontal gyrus appear to play a central role in the pathophysiology of trichotillomania, and to be trait in nature. The findings are distinct from other impulsive-compulsive disorders (OCD, ADHD, gambling disorder), which have typically been associated with reduced, rather than increased, cortical thickness. Future work should examine sub-cortical and cerebellar morphology using analytic approaches designed for this purpose, and should also characterize grey matter densities/volumes.     

Regional frontal abnormalities in schizophrenia: a quantitative gray matter volume and cortical surface size study.

BACKGROUND: Previous structural studies of the frontal lobe in schizophrenia have had somewhat inconsistent results, but most of them have measured the frontal lobe as a single brain structure. To investigate more specific abnormalities in frontal subregions, we measured gray matter volume and cortical surface size in 10 subregions in drug-naive patients during the early stages of the illness. METHODS: Magnetic resonance imaging was used to measure frontal subregions in 34 healthy male volunteers, and 26 male, drug-naive schizophrenia patients at early stages of the illness. Frontal subregions were manually traced using our locally developed parcellation method. RESULTS: Patients with schizophrenia had a significant deficit in cortical surface size in the right straight gyrus and left orbitofrontal cortex. No differences were found in gray matter volumes. CONCLUSIONS: Frontal structural abnormalities found in drug-naive schizophrenic patients appear to be subtle and circumscribed to ventral portions. Anomalies in the cortical surface size suggest neurodevelopmental abnormalities might occur during the early stages of the gyrogenesis. Further investigations are needed to explore the implications of paralimbic ventral frontal regions (i.e., straight gyrus and orbitofrontal cortex) in the pathophysiology of schizophrenia.     

Fields of origin and pathways of the interhemispheric commissures in the temporal lobe of macaques

The interhemispheric connections of the cortical areas of the temporal lobe and some neighboring regions were investigated in monkeys (Macaca mulatta and Macaca fascicularis) by anterograde autoradiographic tracing, following injection of radioactively labeled amino acids. The results revealed that the interhemispheric projections of the temporal lobe course through three interhemispheric commissures on their way to the opposite hemisphere. The anterior commissure receives fibers from virtually the entire temporal lobe, including the temporal pole, superior and inferior temporal gyri, and parahippocampal gyrus. Moreover, area 13 of the orbitofrontal cortex, the frontal and temporal subdivisions of the prepiriform cortex, and the cortical and deep nuclei of the amygdala also contribute fibers to the anterior commissure. The heaviest projections arise in the rostral third of the temporal isocortex. These projections become progressively lighter from more caudal regions. By contrast, the corpus callosum receives fibers from the caudal two-thirds of the temporal lobe, including the temporal pole, superior and inferior temporal gyri, and parahippocampal gyrus. The heaviest projections arise in the caudal third of the temporal lobe and cross primarily in the caudal third of the corpus callosum, including the splenium. Progressively lighter projections arise more rostrally. Fibers from proisocortical and isocortical areas of the posterior parahippocampal gyrus cross in the ventralmost part of the splenium (inferior forceps), whereas cortical areas lateral to the occipitotemporal sulcus give rise to fibers that cross in the caudal part of the body of the corpus callosum and dorsal splenium. The dorsal hippocampal commissure receives fibers exclusively from the parahippocampal gyrus. The fibers of the corpus callosum, hippocampal commissure, and, to a lesser extent, the anterior commissure are intimately associated with the ventricular system as they course through the white matter of the temporal lobe. The fields of origin of the anterior commissure and corpus callosum overlap extensively over the caudal two-thirds of the temporal lobe. The posterior parahippocampal gyrus is unique in that it gives rise to fibers that cross in all three commissures.     

高功能孤独症患儿全脑白质纤维的弥散张量成像研究

目的 分析高功能孤独症患儿的全脑白质纤维的完整性.方法 对18例高功能孤独症患儿(病例组)以及10名年龄、性别、智商与病例组相匹配的健康儿童(对照组)进行全脑弥散张量成像(DTI)测量;应用基于体素的分析方法,比较两组全脑各向异性分数(FA)的差异.使用Spearman相关分析,分析病例组各感兴趣区FA值与儿章期孤独症评定表(CARS)总分及各项目之间的关系.结果 与对照组相比,病例组右侧额下回、左侧额中回及右侧颞下回邻近白质的FA值低(分别为0.67±0.10、0.57±0.09、0.50 ±0.12),左顶上小叶邻近白质的FA值高(0.55±0.15;P<0.001).病例组左额中回邻近白质的FA值与CARS中的与非生命物体的关系的得分呈负相关(r=-0.63,P=0.005).结论 高功能孤独症患儿多个部位的脑白质纤维的完整性受到破坏.