ANATOMO-FUNCTIONAL ORGANIZATION OF SYLVIAN FISSURE TERRITORIES: FROM SENSORY INTEGRATION TO BEHAVIORAL CONTROL

The somatosensory system serves as a critical interface connecting the body with both the external environment and its internal state. Within the lateral fissure, the dorsal bank territories, including the secondary somatosensory cortex, are fundamental for higher-order sensory processing. While it is known their involvement in sensorimotor processing, such as in grasping modulation, the precise functional architecture of these regions remains largely unknown.
In order to address this issue, we employed a multimodal approach to map these regions, performing an unbiased clustering of labeled cells derived from tracer injections in multiple cortical areas and spinal cord sectors. These anatomically defined clusters were then combined and integrated with data from electrical stimulation and electrophysiological recordings performed in dorsal bank areas.
The study reveals the presence of a precise anatomo-functional organization within the Sylvian fissure, in which specific sectors of this region form the core of circuits arranged along a rostro-caudal axis. In particular, these circuits integrate multisensory inputs (tactile, proprioceptive, visual, and vestibular) with motor-related efferent signals in a somatotopic fashion: motor efference copies related to specific effectors are processed in the same regions involved in processing sensory feedback from those effectors, following a gradient going from orofacial representations anteriorly to trunk and lower limb representations posteriorly. By aligning motor prediction with sensory feedback, this architecture could provide the neural mechanism to distinguish self-generated actions from external events, thereby contributing to the emergence of the 'sense of agency'.