Presentation Details
| Don Tucker Finalist: Dopaminergic modulation of cortical motor circuits during gustatory sensorimotor transformation John Chen1, 2, Alfredo Fontanini1, 2. 1Program in Neuroscience, Stony Brook, NY, USA.2Department of Neurobiology and Behavior, Stony Brook, NY, USA |
Abstract
The anterior-lateral motor cortex (ALM) is implicated in the genesis of sensory-guided licking. It remains unknown what neuromodulatory mechanisms mediate ALM function in sensorimotor transformations. One potential mechanism is dopaminergic signaling through D1 receptors (D1Rs) in ALM. We examined dopamine (DA) release and the role of neurons expressing the D1Rs in mice performing a taste-guided, 2-alternative choice task. We chose a taste-guided behavior because tasting and licking are inherently linked, and it is unknown how ALM is involved in the use of gustatory information to guide licking. Mice were trained to discriminate tastants (sucrose or NaCl) sampled from a central spout, plan their response during a delay period and report the identity of the tastant with directional licks towards two reward spouts (lick left vs. lick right). Fiber photometry recording with the DA sensor, GRAB-DA2h, in ALM revealed phasic DA signals related to licking for a taste cue, followed by an enhanced ramping signal for preparation of contralateral licks during the delay period. Calcium imaging in ALM revealed that activity of ALM D1R+ neurons tracked these DA signals, and their responses are distinct from those of non-D1R expressing neurons (D1R-). Weak tuning to specific taste stimuli was found in neurons, regardless of receptor expression. However, D1R+ responses encoded a bias for contralateral lick trials when compared to D1R- responses, with D1R+ population coding also exhibiting stronger direction selectivity during the delay epoch. Finally, optogenetic inhibition of D1R+ neurons during the delay reduced contralateral lick performance. Our findings suggest that cortical DA signaling is a key neuromodulatory mechanism in ALM during taste-guided sensorimotor transformations involving directional licking.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.