Frontal Inf Tri (Left)

Overview

The left Frontal Inf Tri (Left) in the AAL2 atlas corresponds to the triangular part of the left inferior frontal gyrus, a cortical region of the frontal lobe situated anterior to the precentral gyrus and superior to the lateral sulcus. It forms part of the inferior frontal gyrus along with the opercular and orbital parts and is cytoarchitectonically associated with portions of Brodmann areas 44 and 45. This region is critically involved in higher-order language processing, including syntactic and semantic operations, verbal fluency, and aspects of speech production, and is often considered a core component of Broca’s area in the dominant (typically left) hemisphere. It also contributes to cognitive control, working memory for verbal material, and the selection and inhibition of competing linguistic representations. There is no direct Wikipedia article for “Frontal Inf Tri,” but it is part of the Inferior frontal gyrus.

The left inferior frontal gyrus (triangular part; left Frontal Inf Tri in the AAL2 atlas, overlapping Broca’s area) has been implicated in multiple genetic association studies, particularly in GWAS of cortical thickness, surface area, and language-related traits. Large-scale imaging-genetics consortia (e.g., ENIGMA, UK Biobank) have identified common variants in genes such as FOXP2, CNTNAP2, KIAA0319, DCDC2, and ROBO1 associated with left inferior frontal structure and function, often in the context of reading ability, speech and language performance, and phonological processing. Polygenic risk for schizophrenia, bipolar disorder, and major depressive disorder has been linked to altered morphology and activation of this region, with specific loci (for example near ZNF804A and CACNA1C) showing convergent effects on frontotemporal networks that include the left inferior frontal gyrus. Variants influencing general cognitive ability and educational attainment are also associated with differences in left inferior frontal measures, suggesting shared genetic architecture between language, executive control, and broader cognitive traits. Additionally, risk alleles for neurodevelopmental disorders such as autism spectrum disorder and ADHD show effects on fronto-striatal and fronto-temporal circuitry in which the left inferior frontal gyrus is a key hub, highlighting this region as a genetically sensitive node for language, cognitive control, and psychiatric vulnerability.

Overview generated by GPT-4o (2026).

Region ID: 2311
Hemisphere: left
Atlas: AAL2

Frontal Inf Tri (Left) – Black Background (Full Brain)

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Frontal Inf Tri (Left) – White Background (Full Brain)

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Frontal Inf Tri (Left) – Black Background (Hemisphere)

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Frontal Inf Tri (Left) – White Background (Hemisphere)

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Triplanar View – T1 Background

Triplanar View – Ghost Brain