Little is known about whether information transfer at primary sensory thalamic nuclei is modified by behavioral context. Here we studied the influence of previous decisions/rewards on current choices and preceding spike responses of ventroposterior medial thalamus (VPm; the primary sensory thalamus in the rat whisker-related tactile system). We trained head-fixed rats to detect a ramp-like deflection of one whisker interspersed within ongoing white noise stimulation. Using generative modeling of behavior, we identify two task-related variables that are predictive of actual decisions. The first reflects task engagement on a local scale (“trial history”: defined as the decisions and outcomes of a small number of past trials), whereas the other captures behavioral dynamics on a global scale (“satiation”: slow dynamics of the response pattern along an entire session). Although satiation brought about a slow drift from Go to NoGo decisions during the session, trial history was related to local (trial-by-trial) patterning of Go and NoGo decisions. A second model that related the same predictors first to VPm spike responses, and from there to decisions, indicated that spiking, in contrast to behavior, is sensitive to trial history but relatively insensitive to satiation. Trial history influences VPm spike rates and regularity such that a history of Go decisions wouldpredict fewer noise-drivenspikes (but moreregular ones), andmoreramp-drivenspikes. Neuronal activityinVPm, thus, is sensitive to local behavioral history, and may play an important role in higher-order cognitive signaling.
Bibliographical noteFunding Information:
ThisworkwassupportedbyGrantsfromtheDeutscheForschungsgemeinschaft(DFGSCHW577/12-2and14-1) andBMBFCRCNS(01GQ1113)toC.S.,andNSFCRCNS(IOS-1131948)toG.B.S.C.J.W.wassupportedbyGT/EmoryNIH Computational Neuroscience Training Grant (T90DA032466) and the NIH NRSA Pre–doctoral Fellowship (F31NS089412).WethankMaikStüttgenandLauraBusseforadviceaboutbehavioralmodeling,andUrsulaPascht for fabricating the electrode arrays. The authors declare no competing financial interests.
© 2018 the authors.
Copyright 2018 Elsevier B.V., All rights reserved.
- Choice history
- Reward history
- Tactile system
- VPm thalamus