Presentation Details
| In vivo dynamics of dopaminergic circuits in the mouse olfactory bulb Priscilla Ambrosi, Abigail O'Niel, Elizabeth Moss. Oregon Health & Science University, Portland, OR, USA |
Abstract
Sensory perception is shaped by internal states, but the integration of intrinsic and extrinsic signals by sensory circuits is poorly understood. We are using the mouse olfactory system to study how non-sensory cues regulate information processing in sensory circuits. We hypothesize that local dopamine neurons (DANs) in the olfactory bulb (OB) mediate state- and task-dependent changes in odor encoding. Also known as superficial short axon cells (sSACs), OB DANs are well-positioned to orchestrate fast and reversible changes in odor-evoked activity in the OB as they (1) link up to 50 glomeruli, enabling interglomerular communication, (2) modulate the activity of mitral and tufted cells (MTCs), the principal neurons of the OB, via D1, D2 and GABAA receptors, and (3) receive direct inputs from the basal forebrain, a major source of top-down regulation in the brain. Using two-photon imaging of the OB through a chronic cranial window, we are quantifying the spatial-temporal dynamics of OB DAN activity in vivo, as mice are passively exposed to odors or while mice perform odor discrimination tasks. Preliminary experiments targeting the expression of GCaMP8f and JEDI-2P to OB DANs in TH-Cre mice suggest that OB DAN activity is heterogeneous across glomeruli and odor-dependent. In vivo imaging of the DA sensors GRAB-gDA3h and dLight1.3b also supports heterogeneous DA release across and within glomeruli. On-going experiments will reveal the relationship between DAN activity, DA release and MTC activity in the OB of awake vs anesthetized mice, and in behaving mice before and after chemogenetic modulation of OB DANs. Our results will help us better understand the neuromodulation of olfaction and the neural circuits behind flexible stimulus encoding.
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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.
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