Functional connectivity in amygdalar-sensory/(pre)motor networks at rest: new evidence from the Human Connectome Project

the word 'e-motion' derives from the Latin word 'ex-moveo' which literally means 'moving away from something/ somebody'. emotions are thus fundamental to prime action and goal-directed behavior with obvious implications for individual's survival. however, the brain mechanisms underlying the interactions between emotional and motor cortical systems remain poorly understood. a recent diffusion tensor imaging study in humans has reported the existence of direct anatomical connections between the amygdala and sensory/(pre) motor cortices, corroborating an initial observation in animal research. nevertheless, the functional significance of these amygdala-sensory/(pre) motor pathways remain uncertain. more specifically, it is currently unclear whether a distinct amygdala-sensory/(pre) motor circuit can be identified with resting-state functional magnetic resonance imaging (rs-fMRI). this is a key issue, as rs-fMRI offers an opportunity to simultaneously examine distinct neural circuits that underpin different cognitive, emotional and motor functions, while minimizing task-related performance confounds. we therefore tested the hypothesis that the amygdala and sensory/(pre) motor cortices could be identified as part of the same resting-state functional connectivity network. to this end, we examined independent component analysis results in a very large rs-fMRI data-set drawn from the human connectome project (n = 820 participants, mean age: 28.5 years). to our knowledge, we report for the first time the existence of a distinct amygdala-sensory/(pre) motor functional network at rest. rs-fMRI studies are now warranted to examine potential abnormalities in this circuit in psychiatric and neurological diseases that may be associated with alterations in the amygdala-sensory/ (pre) motor pathways (e.g. conversion disorders, impulse control disorders, amyotrophic lateral sclerosis and multiple sclerosis).