The bilateral Left Cerebrum.Frontal Lobe.Precentral Gyrus corresponds to the primary motor cortex (Brodmann area 4) located on the anterior bank of the central sulcus in the frontal lobe of the left cerebral hemisphere. This region contains a somatotopically organized “motor homunculus,” where different body parts are represented in a medial-to-lateral gradient, and plays a key role in the initiation and execution of voluntary movements, particularly fine, fractionated control of contralateral skeletal musculature. Neurons here project via the corticospinal and corticobulbar tracts to brainstem and spinal motor neurons, contributing to precise motor output and motor learning. The precentral gyrus also integrates inputs from premotor and somatosensory cortices, allowing coordinated planning and refinement of movements based on sensory feedback. Precentral gyrus
The bilateral left precentral gyrus (primary motor cortex) has been implicated in multiple genetic and GWAS findings, primarily through imaging-genetics and disorder-related studies rather than region-specific association scans. Variants near genes involved in neurodevelopment, synaptic function, and cytoskeletal dynamics (such as CADM2, BDNF, and CNTNAP2) have been associated with cortical thickness, surface area, or activation patterns in the precentral gyrus in large MRI-based GWAS, reflecting its role in motor and sensorimotor integration. In movement-related disorders, risk variants for amyotrophic lateral sclerosis (e.g., in C9orf72, SOD1, TARDBP) and hereditary spastic paraplegia often correspond to structural or functional abnormalities in the precentral gyrus, while motor symptom severity in Parkinson’s disease has been linked to genetic variation in dopamine-related genes that modulate motor cortex activation. Autism spectrum disorder and attention-deficit/hyperactivity disorder polygenic risk scores show associations with altered precentral gyrus morphology or connectivity, suggesting shared genetic influences on motor planning and social-communicative circuitry. Additionally, GWAS of handedness and motor skill learning have identified loci whose effects appear to be partly mediated by structural or functional variation in the left precentral region, consistent with its involvement in fine motor control and lateralized motor functions.
Overview generated by GPT-4o (2026).
Region ID: 679
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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