Bilateral integration in somatosensory cortex is controlled by behavioral relevance

<p><span><span>Sensory</span> <span>p</span><span>ercep</span><span>tion</span><span> naturally </span><span>requires</span> <span>processing</span> <span>stimuli </span><span>from</span> <span>both sides of the body</span><span>.</span> <span>Yet</span><span>, </span><span>how</span> <span>neurons</span> <span>bind stimulus</span> <span>features</span><span> across the hemispheres to </span><span>create</span><span> a unified </span><span>percept</span><span>ual</span><span> experience</span> <span>remains</span> <span>unknown.</span> <span>To </span><span>address this </span><span>question</span><span>, w</span><span>e </span><span>performed</span><span> large-scale</span> <span>recordings</span><span> from</span> <span>neurons in</span> <span>both</span><span> somatosensory cort</span><span>ices</span><span> (S1)</span> <span>while</span> <span>mice</span> <span>shared information between </span><span>their </span><span>hemispheres</span> <span>and</span><span> discriminate</span><span>d</span><span> between two categories of bilateral </span><span>stimuli</span><span>. </span><span>When </span><span>expert </span><span>mice </span><span>touched</span> <span>stimuli</span> <span>associated with reward</span><span>,</span> <span>they</span> <span>moved their whiskers</span><span> with greater bilateral symmetry</span><span>.</span> <span>During this period,</span> <span>synchronous spiking</span><span> and </span><span>enhanced </span><span>spike-field coupling</span> <span>emerged</span> <span>between</span> <span>the hemispheres</span><span>.</span> <span>This coordinated activity </span><span>was </span><span>absent</span><span> in</span> <span>stimulus</span><span>-matched</span><span> na&iuml;ve animals</span><span>,</span> <span>indicating</span><span> that </span><span>interhemispheric </span><span>(IH)</span> <span>binding</span> <span>was</span> <span>controlled</span> <span>by</span> <span>a</span><span> goal-directed</span><span>,</span> <span>internal </span><span>process</span><span>.</span> <span>I</span><span>n</span> <span>S1 neurons,</span> <span>the addition of ipsilateral touch</span><span> primarily </span><span>facilitate</span><span>d</span> <span>the </span><span>contralateral</span><span>, principal whisker</span><span> response. </span><span>Th</span><span>is</span> <span>facilitation</span> <span>primarily </span><span>emerged</span><span> for</span><span> reward-associated </span><span>stimuli</span> <span>and </span><span>was lost on trials </span><span>where</span> <span>expert </span><span>mice </span><span>failed to</span><span> re</span><span>spond</span><span>.</span> <span>Taken together</span><span>, t</span><span>hese </span><span>results</span><span> reveal </span><span>a</span> <span>novel</span> <span>state-dependent l</span><span>ogic</span> <span>underlying</span> <span>bilateral </span><span>integration</span><span> in S1</span><span>,</span><span> where</span> <span>stimulus</span> <span>binding</span><span> and</span><span> facilitation are controlled by </span><span>behavioral relevance</span><span>.&nbsp;</span></span></p>