The Limbic and Sensorimotor Pathways of the Human Amygdala: A Structural Connectivity Study

The amygdala plays a key role in gathering social cues to context-appropriate responses that require refined motor behavior, involving either direct or indirect connections with sensorimotor-related areas. Although, several studies investigated the structural and functional limbic connectivity of the amygdala both in animals and in humans, less is known about the limbic modulation on sensorimotor-related areas. However, recent evidences suggest the amygdala as a possible cornerstone in the limbic-motor interface. Herein, we used high-resolution diffusion data of the Massachusetts General Hospital-University of Southern California (MGH-USC) Adult Diffusion Dataset, constrained spherical deconvolution-based signal modeling and probabilistic tractography aimed at identifying and reconstructing the connectivity patterns linking the amygdala to the limbic- and sensorimotor-related areas. As regards the limbic network, our results showed that the amygdala has high probability to be connected with the fusiform gyrus and the lateral orbitofrontal cortex. On the other hand, our connectomic analysis revealed a close interplay between the amygdala and the inferior parietal lobule, followed by the postcentral gyrus, the precentral gyrus and the paracentral lobule. The findings of the present study are in line with previous literature and reinforce the idea of the existence of a limbic-motor interface, which is likely to be involved in the emotional modulation of complex functions such as spatial perception and movement computation. Considering that these pathways may play an important role, not on in physiological conditions, but also in pathological context, further studies should be fostered in order to confirm the existence of a limbic-motor interface and its precise functional meaning.