Postcentral (Left)

Overview

The left Postcentral region, corresponding to the postcentral gyrus in the AAL2 atlas, is located in the parietal lobe of the cerebral cortex, posterior to the central sulcus, and forms the primary somatosensory cortex (Brodmann areas 3, 1, and 2). It receives dense thalamocortical projections from the ventral posterior nuclei of the thalamus, conveying tactile, proprioceptive, nociceptive, and thermal information from the contralateral side of the body. Neurons in this region are somatotopically organized, forming a sensory homunculus in which distinct cortical territories represent different body parts, with disproportionate representation of areas requiring fine tactile discrimination (e.g., fingers, lips). Functionally, the left Postcentral region is essential for conscious perception and discrimination of somatosensory stimuli, integration of body surface information, and contributes to sensorimotor integration and higher-order processes such as tactile object recognition and body schema.

The left postcentral gyrus (primary somatosensory cortex) in the AAL2 atlas has been implicated in multiple genetic studies, primarily through imaging genetics and GWAS of brain structure and function. Large-scale neuroimaging GWAS (e.g., ENIGMA, UK Biobank) have identified common variants in genes related to neurodevelopment and synaptic function (such as microtubule-associated and cell-adhesion genes) that influence cortical thickness and surface area of the postcentral region, though specific, consistently replicated loci unique to the left postcentral gyrus are limited. Polygenic risk for schizophrenia, autism spectrum disorder, and attention-deficit/hyperactivity disorder has been associated with altered somatosensory cortex morphology or activation, including left postcentral regions, suggesting that distributed genetic liability for neurodevelopmental disorders affects this area’s structure and connectivity. Variants near genes involved in sensory processing and pain pathways (for example, in sodium channel and nociception-related genes) have been linked to altered somatosensory activation, tactile perception, or pain sensitivity, which show functional correlates in the postcentral cortex. Additionally, GWAS of handedness, motor skills, and body mass index have reported associations with somatosensory and sensorimotor cortical measures encompassing the left postcentral gyrus, indicating that common genetic variants shape individual differences in sensory–motor integration and somatotopic representation, although these effects are typically modest and highly polygenic.

Overview generated by GPT-4o (2026).

Region ID: 6001
Hemisphere: left
Atlas: AAL2

Postcentral (Left) – Black Background (Full Brain)

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Postcentral (Left) – White Background (Full Brain)

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Postcentral (Left) – Black Background (Hemisphere)

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Postcentral (Left) – White Background (Hemisphere)

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Triplanar View – T1 Background

Triplanar View – Ghost Brain