Study: significance of circadian phase for performance on a reward-based learning task in
Past research shows that disrupted circadian rhythms are linked with cognitive
impairment in humans, and impaired performance in animal studies (using shifted L:D
Separate from memory acquisition and memory formation, memory recall is subject to
temporal modulation. In some cases, time of day or phase is a learned attribute along with
other environmental attributes (adaptive significance.) Timing of significant events can
be learned with timed rewards (anticipatory behaviour to food entrainment)
1) perceived reward value of wheel changes through the day. However, response can be
induced at times outside of spontaneous activity.. therefore hypothesize that…
2) response to the reward is temporally restricted. (ie, can acquire place preference at any
time that reward stimulus is high, but expression depends on natural pattern.
Both hypotheses not supported.
CPP expression restricted to the temporal match between training and testing times.
Internal representation of time is a significant attribute of context, even when time is not
a discriminative cue.
Hamsters were entrained for 8 days, half at ZT13 and half at ZT04. Those that were
paired at ZT13 showed place preference at ZT13 (training time) but not for ZT04. The
results were vice-versa for ZT04 group. Hamsters tested in constant light showed the