Hemispheric asymmetry represents a cardinal feature of cerebral organization, but the nature of structural and functional differences between the hemispheres is far from fully understood. Using Magnetic Resonance Imaging morphometry, we identified several volumetric differences between the two hemispheres of the human brain. Heteromodal inferoparietal and lateral prefrontal cortices are more extensive in the right than left hemisphere, as is visual cortex. Heteromodal mesial and orbital prefrontal and cingulate cortices are more extensive in the left than right hemisphere, as are somatosensory, parts of motor, and auditory cortices. Thus, heteromodal association cortices are more extensively represented on the lateral aspect of the right than in the left hemisphere, and modality-specific cortices are more extensively represented on the lateral aspect of the left than in the right hemisphere. On the mesial aspect heteromodal association cortices are more extensively represented in the left than right hemisphere.
"Shading indicates regions where the results of the current study, the results of analysing the OASIS data, and those of previous studies are in agreement. (G = Good et al., 2001; G13 = Goldberg et al., 2013; H = Herve et al., 2006; L = Lyttelton et al., 2009; L6 = Luders et al., 2006; S = Szabo et al., 2006; V = Van Essen et al., 2012; W = Watkins et al., 2001; Z = Zhou et al., 2013) temporal and Heschl's gyrus, as well as relatively increased areas in the LH supramarginal gyrus and the RH middle frontal gyrus. "
[Show abstract][Hide abstract] ABSTRACT: Previous research studies have reported many hemispherical asymmetries in cortical and subcortical anatomy, but only a subset of findings is consistent across studies. Here, we used improved Freesurfer-based automated methods to analyse the properties of the cortex and seven subcortical structures in 138 young adult subjects. Male and female subjects showed similar hemispheric asymmetries in gyral and sulcal structures, with many areas associated with language processing enlarged in the left hemisphere (LH) and a number of areas associated with visuospatial processing enlarged in the right hemisphere (RH). In addition, we found greater (non-directional) cortical asymmetries in subjects with larger brains. Asymmetries in subcortical structures included larger LH volumes of thalamus, putamen and globus pallidus and larger RH volumes of the cerebellum and the amygdala. We also found significant correlations between the subcortical structural volumes, particularly of the thalamus and cerebellum, with cortical area. These results help to resolve some of the inconsistencies in previous studies of hemispheric asymmetries in brain anatomy.
[Show abstract][Hide abstract] ABSTRACT: Abstract The relationship between specific genes and particular diseases in neuropsychiatry is unclear, and newer studies focus on shared domains of neurobiological and cognitive pathology across different disorders. This paper reviews the evidence for an association between schizophrenia and frontotemporal dementia, including symptom similarity, familial co-morbidity, and neuroanatomical changes. Genetic as well as epigenetic findings from both schizophrenia and frontotemporal dementia are also discussed. As a result, we introduce the hypothesis of a shared susceptibility for certain subgroups of schizophrenia and frontotemporal dementia. This common causation may involve the same gene(s) at different stages of life: early in schizophrenia and late in frontotemporal dementia. Additionally, we provide a rationale for future research that should emphasize both genetic and cognitive parallels between certain forms of schizophrenia and frontotemporal dementia in a synergistic, coordinated way, placing both in the context of aberrant lateralization patterns.
International Review of Psychiatry 04/2013; 25(2):168-77. DOI:10.3109/09540261.2013.765389 · 1.80 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background and purpose:
Automated anatomical labeling (AAL) provides an automatic brain region segmentation method to allow objective measurement of regional brain volume. Nonlinear registration plays a critical role in such automated region-based volumetry. The aim of this study was to compare age-related brain regional volume changes using two nonlinear registration methods in statistical parametric mapping (SPM).
Material and methods:
The study included 176 right-handed healthy participants (age range: 18-94years). A total of 90 brain regions for each subject were automatically extracted, based on the AAL atlas, and two nonlinear registration methods (Normalization and DARTEL Toolbox in SPM5) were applied. Three-way ANOVA was performed to estimate the effects of brain region, each registration method and each hemisphere on regional volumes. Age-related brain-volume changes were also investigated by linear regression analysis for each nonlinear registration method.
Significant differences were found in volume among different brain regions (P<0.001) with the two nonlinear registration methods (P=0.011). Volumes of the corresponding brain region were significantly different (P=0.037) between two hemispheres, and age-related volume reductions were unevenly distributed across regions. The most dramatic decreases in volume were found in the bilateral insula, middle frontal regions and cingulum. Rankings of the decreased brain regional volumes differed between the two registration techniques and adjustment methods.
The inferred age-related volume atrophy patterns based on the AAL atlas were largely dependent on the choice of registration methodology.
Journal of Neuroradiology 04/2013; 40(5). DOI:10.1016/j.neurad.2013.01.004 · 1.75 Impact Factor
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