Mesial Temporal to Motor Cortex Connectivity Is Modulated by Motor Control

Introduction: Recent evidence has suggested that activity in mesial temporal structures is modulated during movement and motor control. However, how mesial temporal structures interact with motor circuitry to modulate movement remains unknown. The primary objective of this study is to evaluate connectivity between limbic and motor regions during motor control.

Methods: Local field potentials (LFPs) were recorded from 6 epilepsy patients implanted with intracranial depth electrodes for seizure localization purposes. Participants performed the stop-signal task, during which they made speeded choice reactions to “go” stimuli and occasionally inhibited their reactions in the incident of a “stop” signal. We computed z-scored partial directed coherence (PDC) between the motor cortex, amygdala, and hippocampus in beta (13 to 30 Hz) and gamma (31 to 150Hz) frequencies for correct go and correct stop trials. We used Wilcoxon signed rank tests to compare PDC during stopping to that during going.

Results: We found higher amygdala-to-motor cortex and motor cortex-to-amygdala gamma PDC values during stopping compared to going. Amygdala-to-motor cortex demonstrated a mean difference (Stop – Go) of 0.695 ± 0.326 (SD) (r = 0.90, p = 0.031) and motor cortex-to-amygdala demonstrated a mean difference of 0.663 ± 0.387 (SD) (r =0.90, p = 0.031). There were no significant beta PDC differences between stopping and going.

Conclusion : The findings from this study highlight a differential pattern of connectivity between the amygdala and motor cortex during motor inhibition compared to movement. The increased connectivity between the amygdala-to-motor cortex pathway during stopping points to a potential facilitatory role of the amygdala in movement inhibition.