Forebrain monoamines and associative learning: III. The US pre-exposure effect.
This experiment evaluated the effects of forebrain norepinephrine (NE) and serotonin depletion on the unconditioned stimulus (US) pre-exposure phenomenon. Rats with either dorsal bundle lesions, raphe lesions, or which served as vehicle controls were assigned to one of two training conditions. One-half of the animals in the 3 lesion groups received 30 episodes of a stimulus which later served as the US. The remaining rats experienced standard conditioning of CS-US pairing without US pre-exposure. The results indicate that while raphe-lesioned and vehicular rats exhibited the US pre-exposure effect, conditioning was unimpaired in NE-depleted rats following pre-exposure. These findings are consistent with a contextual blocking interpretation of the US pre-exposure effect.
Rickert
E J
EJ
Department of Psychology, University of Alabama, Birmingham 35294.
Lorden
J F
JF
D000818:Animals; D001245:Association Learning / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D003214:Conditioning, Classical / Q000502:physiology*; D007858:Learning; D008297:Male; D008568:Memory; D011939:Mental Recall / Q000502:physiology*; D009638:Norepinephrine / Q000502:physiology*; D011903:Raphe Nuclei / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000502:physiology; D011985:Receptors, Serotonin / Q000502:physiology; D012701:Serotonin / Q000502:physiology*
D011941:Receptors, Adrenergic; D011985:Receptors, Serotonin; D012701:Serotonin; D009638:Norepinephrine