How movements are selected is a fundamental question in systems neuroscience. While many studies have elucidated the sensorimotor transformations underlying stimulus-guided movements, less is known about how internal goals - critical drivers of goal-directed behavior - guide movements. The basal ganglia are known to bias movement selection according to value, one form of internal goal. Here, we examine whether other internal goals, in addition to value, also influence movements via the basal ganglia. We designed a novel task for mice that dissociated equally rewarded internally-specified and stimulus-guided movements, allowing us to test how each engaged the basal ganglia. We found that activity in the substantia nigra pars reticulata, a basal ganglia output, predictably differed preceding internally-specified and stimulus-guided movements. Incorporating these results into a simple model suggests that internally-specified movements may be facilitated relative to stimulus-guided movements by basal ganglia processing.
Animal experimentation: This study was performed in accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health, 8th edition. All experiments were performed according to protocol #90209(12)1D, approved by the University of Colorado School of Medicine Institutional Animal Care and Use Committee. All surgeries were performed under isoflurane anesthesia and all perfusions were performed following an overdose of sodium pentobarbital. Quality of life was improved with enriched living environments and dietary treats while every effort was made to minimize suffering.
- Rui M Costa, Fundação Champalimaud, Portugal
© 2016, Lintz & Felsen
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