title: Context-Dependent Duration Signals in the Primate Prefrontal Cortex.
abstract: The activity of some prefrontal (PF) cortex neurons distinguishes short from long time intervals. Here, we examined whether this property reflected a general timing mechanism or one dependent on behavioral context. In one task, monkeys discriminated the relative duration of 2 stimuli; in the other, they discriminated the relative distance of 2 stimuli from a fixed reference point. Both tasks had a pre-cue period (interval 1) and a delay period (interval 2) with no discriminant stimulus. Interval 1 elapsed before the presentation of the first discriminant stimulus, and interval 2 began after that stimulus. Both intervals had durations of either 400 or 800 ms. Most PF neurons distinguished short from long durations in one task or interval, but not in the others. When neurons did signal something about duration for both intervals, they did so in an uncorrelated or weakly correlated manner. These results demonstrate a high degree of context dependency in PF time processing. The PF, therefore, does not appear to signal durations abstractedly, as would be expected of a general temporal encoder, but instead does so in a highly context-dependent manner, both within and between tasks.
authors.affiliation: Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.
authors.forename: Aldo
authors.initials: A
authors.lastname: Genovesio
authors.affiliation: Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.
authors.forename: Lucia K
authors.initials: LK
authors.lastname: Seitz
authors.affiliation: Department of Intelligence Science and Technology, Graduate School of Informatics, Kyoto University, Kyoto, Japan Nielsen Neuro, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsujimoto
authors.affiliation: Olschefskie Institute for the Neurobiology of Knowledge, Potomac, MD 20854, USA Edmond and Lily Safra International Institute of Neurosciences of Natal, Natal, Brazil.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Wise
mesh_terms: D000200:Action Potentials; D000704:Analysis of Variance; D000818:Animals; D003463:Cues; D004192:Discrimination, Psychological / Q000502:physiology*; D006225:Hand / Q000502:physiology; D008253:Macaca mulatta; D008297:Male; D008839:Microelectrodes; D009043:Motor Activity / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D013998:Time Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology
keywords: dorsolateral prefrontal cortex; duration; executive function; monitoring; periprincipal prefrontal cortex; temporal processing; timing