GM Primary somatosensory cortex BA3a R

Overview

The bilateral GM Primary somatosensory cortex BA3a R, as defined in the Juelich maxprob thr25 2 mm atlas, corresponds to the granular cortical field Brodmann area 3a located in the posterior bank of the central sulcus within the postcentral gyrus. This region forms part of the primary somatosensory cortex and is particularly associated with processing proprioceptive input from muscles and joints, receiving strong thalamocortical projections (notably from the ventral posterior nucleus). Neurons in BA3a exhibit small receptive fields and are involved in fine-grained encoding of body position and movement, contributing to sensorimotor integration and modulation of motor output via dense connections with motor-related cortical areas. There is no direct Wikipedia article for “BA3a,” but it is a subregion of the Primary somatosensory cortex.

Genetic associations specific to the bilateral GM Primary somatosensory cortex BA3a R (as defined in the Juelich maxprob thr25 2mm atlas) are indirect and largely inferred from broader studies of somatosensory and sensorimotor cortices rather than BA3a itself. Large-scale neuroimaging GWAS, such as ENIGMA and UK Biobank studies, have identified multiple loci influencing cortical thickness and surface area in the parietal and sensorimotor regions, including genes involved in neurodevelopment (e.g., MAPT, PAX6, and variants near microtubule and synaptic pathways), but these are typically reported at lobar or regional scales rather than at the fine-grained cytoarchitectonic level of BA3a. Somatosensory and motor cortex structures, encompassing BA3a, have been implicated in polygenic architectures of disorders affecting sensorimotor function and cortical morphology, including schizophrenia, autism spectrum disorder, ADHD, and epilepsy, where risk variants in synaptic, calcium-channel, and neurodevelopmental genes are associated with altered cortical thickness or surface area in primary sensorimotor regions. Pain-related GWAS and imaging-genetics studies have also identified variants in genes such as COMT and OPRM1 and in broader neuroinflammatory pathways that modulate activation and structural properties of primary somatosensory areas during nociceptive processing, although associations are not resolved to BA3a specifically. Overall, current genetic evidence links somatosensory cortex morphology and function—including regions overlapping BA3a—to polygenic influences on neurodevelopment, sensorimotor integration, and psychiatric and neurological disorders, but precise gene–region mapping for BA3a R as defined in the Juelich atlas remains limited.

Overview generated by GPT-4o (2026).

Region ID: 56
Hemisphere: bilateral
Atlas: Juelich maxprob thr25 2mm

GM Primary somatosensory cortex BA3a R – Black Background (Full Brain)

Full Quality Version: Download MP4

GM Primary somatosensory cortex BA3a R – White Background (Full Brain)

Full Quality Version: Download MP4

Triplanar View – T1 Background

Triplanar View – Ghost Brain