The bilateral Left Cerebrum.Temporal Lobe.Middle Temporal Gyrus.Gray Matter.Brodmann area 20 corresponds to a ventral portion of the temporal neocortex located in the middle temporal gyrus of the left hemisphere, implicated in higher-order visual and semantic processing. Brodmann area 20 is cytoarchitectonically defined by its granular cortical layering and is associated with object recognition, integration of visual form and meaning, and aspects of language comprehension, particularly lexical–semantic access. Functionally, it participates in the ventral visual stream, contributing to the interpretation of complex visual stimuli and linking these representations to stored semantic knowledge. There is no direct Wikipedia article for “Brodmann area 20,” but it is part of the broader middle temporal gyrus region: Middle temporal gyrus.
The bilateral left middle temporal gyrus gray matter in Brodmann area 20 (BA20), part of the ventral temporal cortex implicated in semantic memory, language, and higher-order visual processing, has been linked indirectly to several genetic associations through neuroimaging–genetics and GWAS studies of brain structure and cognition rather than through BA20-specific analyses. Large-scale GWAS of cortical thickness and surface area (e.g., ENIGMA and UK Biobank) have identified variants near genes such as CRTC1, TCF4, PLEKHM1, and KIAA0586 that influence temporal lobe morphology, including inferior and middle temporal regions overlapping BA20, and these structural measures in turn associate with verbal ability, reading, and general cognitive performance. Polygenic risk scores for schizophrenia, autism spectrum disorder, and major depressive disorder have been associated with gray matter alterations and connectivity changes in the middle and inferior temporal gyri, suggesting that common risk variants for these conditions partially exert effects via temporal cortical circuitry that includes BA20. In Alzheimer’s disease and frontotemporal dementia, GWAS-identified loci such as APOE, BIN1, and MAPT are related to atrophy patterns and hypometabolism in ventral and lateral temporal regions, including BA20, consistent with the region’s role in semantic processing and object recognition that is frequently impaired in these disorders. In language-related traits, variants near FOXP2 and CNTNAP2 and polygenic scores for educational attainment and cognitive performance show associations with activation and structural measures in the temporal language network, which encompasses the middle temporal gyrus, though these findings typically refer to broader temporal ROIs rather than Talairach-defined BA20 specifically. Overall, current genetic evidence links common and rare variants affecting neurodevelopment, synaptic function, and neurodegeneration to structural and functional variation in the temporal lobe network that includes BA20, but highly specific GWAS focused solely on bilateral left BA20 gray matter are not yet available, and most associations are inferred from broader temporal cortex measures.
Overview generated by GPT-4o (2026).
Region ID: 23
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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