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Updated: Dec 21, 2025

Measuring and Manipulating Functionally Specific Neural Pathways in the Human Motor System with Transcranial Magnetic Stimulation
Published on: February 23, 2020
Functional network analysis of the sub-regions of the primary motor cortex during rest
1Department of Radiologic Sciences, College of Applied Medical Sciences, King Abdulaziz University (KAU), Jeddah, Saudi Arabia.
Abstract:
The cytoarchitectonic properties of the primary motor cortex have shown two distinct sub-regions: Anterior Broadmann area 4 (BA4a) and Posterior Broadmann area 4 (BA4p). Some previous studies have suggested that these two sub-regions are functionally different and showed that in few fMRI experiments, these sub-regions may have different roles in brain functions. Resting-state fMRI (rsfMRI) is advanced technique that allows investigating in detail the functional connectivity and provides a greater understanding of the physiological behavior of different brain regions. In this study, 198 healthy subjects were examined using a region-based rsfMRI analysis to investigate whether BA4a and BA4p have similar or different connections to other brain networks. The finding shows that indeed these two sub-regions have distinct connectivity to different brain networks. BA4a has a greater connection to motor-related areas while BA4p has connections to nonmotor-related areas (such as sensory, attentional, and higher order regions), suggesting that these two sub-regions should be considered as two separate regions of interests.

