Study On The Neural Mechanism Of The Representation Of Time Information In Striatum

Given the dynamic nature of the word,it is the fundamental skill that living organisms owned to estimate time and predict its consequence.This timing ability is of critical importance to inter-temporal decision making,sensory integration and motor coordination.As striatum is noted for its encoding reinforcement learning and procedural motion,it is required to represent temporal information precisely to guide actions in proper sequence,from a muscle group to another or guided by external sensory cues,such as playing a musical piece,jump-shooting at the basket and waiting the sound of gun to start of a race.Previous studies suggest the striatum may play a role of ‘core timer' and dysfunction of striatum,like Parkinson's disease,much common represent with timing disorder.However,little is known about the striatal ensembles encode time on subseconds-to-seconds range.To address this question,a fix interval reproduction task is designed which requires the rats to reproduce a fix duration by a robust action.By recording from dorsomedial striatum in rats performing the task,we found that striatal neurons,especially the fast-spiking subpopulation,exhibited a ‘ramping' modulation align to the ‘start-timing' cue.Furthermore,our data implied that the dynamic activities of such timing-relevant units embodied both the current duration and recent outcomes information to predict and drive the following action,which point to an empirical strategy may be adopted by rats to calibrate their timing behavior.Above all,we investigated the firing rate modulation and potential calibration mechanism of the timing – relevant striatal neurons.These results revealed the neural mechanism of time information processing and might help to explain the neural basis of motor coordination underlie some physiological or pathological conditions.