Bilateral GM Broca’s area BA45 L, as defined in the Juelich maxprob thr25 2mm Atlas, corresponds predominantly to the pars triangularis of the inferior frontal gyrus in the left hemisphere, a key portion of the inferior frontal cortex involved in higher-order language functions. Cytoarchitectonically classified as Brodmann area 45, this region is characterized by granular frontal cortex and distinct laminar organization associated with semantic processing, controlled retrieval of lexical information, and aspects of syntactic integration. Functionally, BA45 forms part of the broader “Broca’s complex,” interacting with adjacent BA44 and temporal–parietal language areas via dorsal and ventral pathways to support speech production, comprehension, and verbal working memory, particularly in the dominant (usually left) hemisphere. There is no dedicated Wikipedia page for “BA45” as a standalone entry; a closely related and encompassing structure is Broca’s area.
Broca’s area BA45 in the left inferior frontal gyrus, as defined in the Juelich maxprob atlas, has been implicated in genetic studies of language, speech, and higher cognitive functions, although most associations are indirect via broader cortical or language networks rather than this parcel specifically. GWAS and imaging-genetics studies have identified common variants in genes influencing cortical thickness and surface area (such as those in the MAPT, KIAA0586, and microtubule-related pathways) that show effects in frontal language regions, including left inferior frontal cortex encompassing BA45. FOXP2, CNTNAP2, and DCDC2, key genes in speech and language, developmental language disorder, and dyslexia, have been repeatedly linked to structural and functional variation in the left fronto-temporal language network, with convergent evidence of altered activation and connectivity in inferior frontal regions overlapping BA45. Large-scale neuroimaging GWAS (e.g., ENIGMA and UK Biobank) have shown polygenic influences on frontal language areas through variants associated with general cognitive ability, educational attainment, and reading-related traits, implicating synaptic, neuronal migration, and axon guidance genes that modulate activity in BA45 as part of a distributed language network. Psychiatric GWAS for schizophrenia, autism spectrum disorder, and major depressive disorder indicate that risk alleles affecting synaptic function and cortical development are associated with atypical structure and connectivity in left inferior frontal regions, including BA45, which are commonly reported as sites of altered activation during language and executive tasks. Overall, genetic influences on BA45 appear to act through polygenic effects on cortical development and network-level language and cognitive systems rather than through variants uniquely specific to this region.
Overview generated by GPT-4o (2026).
Region ID: 15
Hemisphere: bilateral
Atlas: Juelich maxprob thr25 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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