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Sequence learning induces selectivity to multiple task parameters in mouse somatosensory cortex
journal contribution
posted on 2023-06-09, 22:11 authored by Michael Bale, Malamati Bitzidou, Elena Giusto, Paul Francis KinghornPaul Francis Kinghorn, Miguel Maravall RodriguezMiguel Maravall RodriguezSequential temporal ordering and patterning are key features of natural signals, used by the brain to decode stimuli and perceive them as sensory objects. To explore how cortical neuronal activity underpins sequence discrimination, we developed a task in which mice distinguished between tactile “word” sequences constructed from distinct vibrations delivered to the whiskers, assembled in different orders. Animals licked to report the presence of the target sequence. Mice could respond to the earliest possible cues allowing discrimination, effectively solving the task as a “detection of change” problem, but enhanced their performance when responding later. Optogenetic inactivation showed that the somatosensory cortex was necessary for sequence discrimination. Two-photon imaging in layer 2/3 of the primary somatosensory “barrel” cortex (S1bf) revealed that, in well-trained animals, neurons had heterogeneous selectivity to multiple task variables including not just sensory input but also the animal’s action decision and the trial outcome (presence or absence of the predicted reward). Many neurons were activated preceding goal-directed licking, thus reflecting the animal’s learned action in response to the target sequence; these neurons were found as soon as mice learned to associate the rewarded sequence with licking. In contrast, learning evoked smaller changes in sensory response tuning: neurons responding to stimulus features were found in naive mice, and training did not generate neurons with enhanced temporal integration or categorical responses. Therefore, in S1bf, sequence learning results in neurons whose activity reflects the learned association between target sequence and licking rather than a refined representation of sensory features.
Funding
Sensory sequence representation and discrimination in cortical circuits; G1975; MRC-MEDICAL RESEARCH COUNCIL; MRC Ref: MR/P00
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- Published
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- Published version
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Current BiologyISSN
0960-9822Publisher
ElsevierExternal DOI
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3Volume
31Page range
473-485Department affiliated with
- Neuroscience Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2020-11-16First Open Access (FOA) Date
2020-11-16First Compliant Deposit (FCD) Date
2020-11-16Usage metrics
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