Two-photon imaging in mice shows striosomes and matrix have overlapping but differential reinforcement-related responses

Striosomes were discovered several decades ago as neurochemically identified zones in the striatum, yet technical hurdles have hampered the study of the functions of these striatal compartments. Here we used 2-photon calcium imaging in neuronal birthdate-labeled Mash1- CreER;Ai14 mice to image simul...

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Bibliographic Details
Main Authors: Bloem, Bernard, Huda, Rafiq, Sur, Mriganka, Graybiel, Ann M
Other Authors: Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences
Format: Article
Published: eLife Sciences Publications, Ltd 2018
Online Access:http://hdl.handle.net/1721.1/113562
https://orcid.org/0000-0002-0930-580X
https://orcid.org/0000-0002-6814-9966
https://orcid.org/0000-0003-2442-5671
https://orcid.org/0000-0002-4326-7720
Description
Summary:Striosomes were discovered several decades ago as neurochemically identified zones in the striatum, yet technical hurdles have hampered the study of the functions of these striatal compartments. Here we used 2-photon calcium imaging in neuronal birthdate-labeled Mash1- CreER;Ai14 mice to image simultaneously the activity of striosomal and matrix neurons as mice performed an auditory conditioning task. With this method, we identified circumscribed zones of tdTomato-labeled neuropil that correspond to striosomes as verified immunohistochemically. Neurons in both striosomes and matrix responded to reward-predicting cues and were active during or after consummatory licking. However, we found quantitative differences in response strength: striosomal neurons fired more to reward-predicting cues and encoded more information about expected outcome as mice learned the task, whereas matrix neurons were more strongly modulated by recent reward history. These findings open the possibility of harnessing in vivo imaging to determine the contributions of striosomes and matrix to striatal circuit function.