Long-lasting memory of sounds combined with reward in rats.
We investigated the effects of sound stimuli combined with reward on the subsequent sound discrimination. Water-deprived rats were exposed to one of two sounds (S+ or S-) in a trial, and licking a spout only during the presentation of S+ was rewarded with water. The percentage of trials in which licking occurred was calculated separately for S+ and S-, and sound discrimination was estimated from the difference in the percentage. S+ and S- were significantly discriminated during an 8 h period. In the second test after 1-2 weeks, sound discrimination for the same S+ and S- was significantly better than that for the S+ of the previous S- and S- of the previous S+. These findings indicate that the memory of the sounds combined with reward in the first test was maintained for 1-2 weeks.
Watanabe
S
S
Department of Neurophysiology, Brain Research Institute, Niigata University, 1 Asahi-machi, 951-8585, Niigata, Japan.
Kudoh
M
M
Ohnishi
K
K
Shibuki
K
K
D000161:Acoustic Stimulation / Q000295:instrumentation / Q000379:methods*; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology*; D009483:Neuropsychological Tests / Q000592:standards*; D010897:Pitch Discrimination / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012201:Reward; D014868:Water Deprivation / Q000502:physiology