title: Representation of interval timing by temporally scalable firing patterns in rat prefrontal cortex.
abstract: Perception of time interval on the order of seconds is an essential component of cognition, but the underlying neural mechanism remains largely unknown. In rats trained to estimate time intervals, we found that many neurons in the medial prefrontal cortex (PFC) exhibited sustained spiking activity with diverse temporal profiles of firing-rate modulation during the time-estimation period. Interestingly, in tasks involving different intervals, each neuron exhibited firing-rate modulation with the same profile that was temporally scaled by a factor linearly proportional to the instructed intervals. The behavioral variability across trials within each task also correlated with the intertrial variability of the temporal scaling factor. Local cooling of the medial PFC, which affects neural circuit dynamics, significantly delayed behavioral responses. Thus, PFC neuronal activity contributes to time perception, and temporally scalable firing-rate modulation may reflect a general mechanism for neural representation of interval timing.
authors.affiliation: Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.forename: Si-yu
authors.initials: SY
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Dan
authors.forename: Mu-ming
authors.initials: MM
authors.lastname: Poo
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal; D004594:Electrophysiology; D007858:Learning; D008297:Male; D008959:Models, Neurological; D009043:Motor Activity / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D017397:Prefrontal Cortex / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D013998:Time Perception