Delayed changes of sleep duration after rewarded olfactory discrimination learning in the rat.
The aim of this experiment was to determine if a task of associative olfactory learning, based on the ethological repertory of rats and learnt rapidly in 5 successive trials, could modify slow wave sleep (SWS) and/or paradoxical sleep (PS) duration after learning and/or after a retrieval-reactivation test 24 h later. Somnopolygraphic recordings were performed for 20 h per day on trained and control (submitted to a pseudo-learning test) rats. SWS and PS durations were analyzed per 20 h and per 4 h time-periods. Compared to control rats, after learning, trained rats showed a significant increase in SWS duration counterbalanced by a significant decrease in wake duration focused on the 5-8 h post-training time-window and a significant decrease in PS duration during the 17-20 h post-training time-window. After the retrieval-reactivation test trained rats only showed a decreased PS duration compared to control rats submitted to a pseudo-retrieval test. Thus, a rather simple learning task succeeded in eliciting an increase in SWS duration in a limited time-window. As the learning task used can be compared to human associate-paired learning, this result sustains the hypothesis of a link between declarative memory and SWS. In control rats, changes in PS duration might be linked to odorized-environment exposure.
Magloire
Vincent
V
Université de Lyon - EA 4170, Université Lyon 1, 8 avenue Rockefeller, 69373 Lyon cedex 08, France.
Cattarelli
Martine
M
D000818:Animals; D001245:Association Learning; D004193:Discrimination Learning; D004567:Electrodes, Implanted; D006185:Habituation, Psychophysiologic; D008297:Male; D009483:Neuropsychological Tests; D055696:Olfactory Perception; D017286:Polysomnography; D051381:Rats; D017208:Rats, Wistar; D012201:Reward; D012890:Sleep; D012895:Sleep, REM; D013997:Time Factors; D014851:Wakefulness