The bilateral Right Cerebrum.Temporal Lobe.Inferior Temporal Gyrus.Gray Matter.Brodmann area 21 corresponds to a portion of the association cortex in the middle to inferior temporal region, primarily involved in higher-order auditory and visual processing, semantic memory, and aspects of language comprehension. Brodmann area 21 is characterized cytoarchitectonically by a well-developed granular layer and prominent pyramidal neurons in layers III and V, and it participates in networks that integrate complex object features, facial recognition, and lexical–semantic information. Functionally, this region contributes to the processing of spoken and written language, the interpretation of complex visual stimuli, and the integration of multimodal sensory inputs within temporal association pathways. There is no direct link for this exact composite label; a related structure is Brodmann area 21.
Bilateral gray matter in the right (and more broadly temporal) inferior temporal gyrus corresponding to Brodmann area 21 has been implicated in multiple genetic and GWAS findings, largely through imaging-genetics and disorder-risk studies rather than single-region candidate approaches. Common variants in genes affecting synaptic function, neurodevelopment, and glutamatergic signaling (for example, GRIN2B, NRGN, DISC1, and several calcium-channel and synapse-related loci) have been associated with temporal lobe cortical thickness, surface area, or gray-matter volume in large ENIGMA and UK Biobank analyses, which include BA21 or adjacent middle/inferior temporal regions. Polygenic risk scores for schizophrenia, autism spectrum disorder, and major depressive disorder frequently correlate with structural or functional alterations in this area, consistent with its role in language, semantic processing, and higher-order visual recognition; temporal BA21 involvement is reported in GWAS-informed imaging studies of schizophrenia (e.g., ZNF804A, CACNA1C loci), autism (genes involved in synaptic development and FOXP2-related networks), and mood disorders. In addition, APOE and other Alzheimer’s disease risk loci show associations with temporal cortical atrophy and metabolic changes extending into BA21, while GWAS of cognitive traits (general intelligence, verbal ability, and educational attainment) often report temporal lobe–linked loci whose effects are partly mediated through variation in gray-matter structure and connectivity in this region. Overall, genetic influences on Brodmann area 21 appear polygenic and shared across neuropsychiatric and cognitive traits, with no single locus uniquely specific to this Talairach-defined region but strong convergence from large-scale imaging-genetics and disease GWAS.
Overview generated by GPT-4o (2026).
Region ID: 77
Hemisphere: bilateral
Atlas: Talairach labels 1mm
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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