Bilateral Left Cerebrum Parietal Lobe Sub-Gyral Gray Matter Brodmann area 40 corresponds primarily to the supramarginal gyrus and adjacent inferior parietal cortex, a multimodal association region involved in integrating somatosensory, auditory, and visual information. This area plays key roles in language processing (especially phonological and lexical aspects), verbal working memory, and the mapping of sounds to articulatory gestures, as well as contributing to spatial attention, body representation, and action understanding. Its gray matter circuits are richly interconnected with temporal and frontal language regions, sensorimotor cortices, and subcortical structures, supporting complex cognitive operations such as reading, speech perception, and praxis. There is no direct link for “Brodmann area 40,” but it is closely associated with the Supramarginal gyrus.
The bilateral left parietal sub-gyral gray matter in Brodmann area 40 (supramarginal/angular region) has been implicated in multiple genetically influenced cognitive and neuropsychiatric phenotypes, although most associations come from imaging genetics and GWAS of cortical measures rather than Talairach-specific labels. Large GWAS of brain structure (e.g., ENIGMA, UK Biobank) have identified common variants near genes such as CENPW, HMGA2, KIAA0586, and others associated with parietal cortical thickness and surface area, reflecting polygenic influences on BA40 morphology. Functionally, BA40 plays a central role in language, phonological processing, working memory, and multimodal integration, and genetic studies linking FOXP2, CNTNAP2, DCDC2, and KIAA0319 to language impairment and dyslexia have repeatedly highlighted left parietal-temporal circuits, including supramarginal/angular gyri. Neurodevelopmental GWAS and CNV analyses in autism spectrum disorder, ADHD, and schizophrenia report risk variants that alter parietal connectivity and gray-matter density, often involving synaptic and neurodevelopmental genes (e.g., NRXN1, DISC1, CACNA1C, GRIN2A), with altered activation or structure in BA40 during language, attention, and working-memory tasks. In Alzheimer’s disease and other dementias, APOE ε4 and additional GWAS loci (e.g., CLU, PICALM, BIN1) are associated with parietal atrophy and hypometabolism, including BA40, which is part of the posterior default-mode and language networks vulnerable to amyloid and tau pathology. Educational attainment and general cognitive ability GWAS (implicating genes such as MAPT, SLC39A8, and multiple polygenic influences) show that higher polygenic scores correlate with increased parietal cortical thickness and enhanced activation in regions encompassing BA40 during numerical and verbal tasks. Overall, genetic influences on BA40 are highly polygenic and shared across cognition, language, and psychiatric risk, with specific loci typically exerting distributed effects across parietal and temporal association cortices rather than being uniquely tied to this single Talairach-defined region.
Overview generated by GPT-4o (2026).
Region ID: 999
Hemisphere: bilateral
Atlas: Talairach labels 2mm
Full Quality Version: Download MP4
Full Quality Version: Download MP4
Wali Sidiqyar*, Gaurav Rudravaram*, Elyssa M. McMaster, Trent M. Schwartz, Adam M. Saunders, Kurt G. Schilling, Bennett A. Landman "Introducing SPINS: A Shared Public Visualization Library of Neuroanatomical Structures." Medical Imaging with Deep Learning- short paper
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