Cain SW, Rawashdeh OA, Siu M, Kim SC, Ralph MR. Dopamine dependent setting of a circadian oscillator underlying the memory for time of day.
Neurobiol Learn Mem 2017;
141:78-83. [PMID:
28366864 DOI:
10.1016/j.nlm.2017.03.015]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 03/17/2017] [Accepted: 03/23/2017] [Indexed: 01/15/2023]
Abstract
Animals learn and remember the time of day that significant conditions occur, and anticipate recurrence at 24-h intervals, even after only one exposure to the condition. On several place-conditioning tasks, animals show context avoidance or preference only near the time of day of the experience. The memory for time of day is registered by a circadian oscillator that is set at the time of the training. We show that manipulations of dopamine (DA) neurotransmission can set a time memory in place preference and avoidance tasks, indicating that time of day is part of the context that is learned. Single injections of the DA agonist, d-amphetamine sulfate given without further exposure to the conditioning apparatus, can reset the timing of anticipatory behavior evoked by previously acquired place-event associations. The data support a model for time memory in which DA signaling sets the phase of a circadian oscillator, which returns to the same state at regular 24-h intervals. The data also raise the possibility that some apparent impairments of memory formation or retention could reflect post-experience resetting of the optimal retrieval time rather than impairment of memory or retrieval per se.
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