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Authors & Affiliations
Alicia Alonso-Andres, Roberto Montanari, Javier Alegre-Cortés, Jorge Cabrera-Moreno, Ismael Navarro, Cristina García-Frigola, María Sáez, Ramón Reig
Abstract
The corpus callosum enables the transfer of information between cerebral hemispheres. In the context of somatosensory stimuli, each hemisphere predominantly processes information originating from the contralateral side of the body through thalamocortical innervation. To a lesser extent, information from the ipsilateral side is also processed and relies on the involvement of callosal axons. We aim to understand the role of these callosal axons in ipsilateral signaling. To study this, we employ the mice whisker system due to its clear somatotopical organization by which the input from a whisker follicle is processed mainly in a specific region (i.e barrel) of the mouse barrel cortex (BC). By means of behavioral, electrophysiological and anatomical tracing experiments we found that row A barrels act as a sensory hub for the interhemispheric transmission. This region receives the input from row A whiskers, located in the midline of the mouse snout. In addition, in vivo whole-cell patch-clamp has revealed that neurons in row A of BC show more vigorous responses to ipsilateral stimulation, closely resembling their contralateral counterparts. Finally, extracellular multielectrode recordings in multiple barrels simultaneously indicate that there is an activity gradient centered around the row A barrels. This becomes relevant when studying the exploratory behavior of mice after row A inactivation, as assessed through a bilateral tactile discrimination task. All in all, our work sheds light on the mechanism of callosal transmission in the mouse BC, as well as its functional relevance.