Conditional discrimination learning in patients with bilateral medial temporal lobe amnesia.
The ability of bilateral medial temporal lobe amnesic patients (MT; n=8) and normal participants (NC; n=8) to acquire a conditional discrimination in trace and delay eyeblink conditioning paradigms was investigated. Experiment 1 assessed trace conditional discrimination learning by using a light conditional stimulus (S+/S-) and tone conditioned stimulus (CS) separated by a 1-s trace. NCs responded differentially on S+ trials (mean percent conditioned responses=66) versus S- trials (30). Whereas MTs were impaired in their acquisition of the conditional discrimination (S+ =51, S- =43). In Experiment 2, the temporal separation was eliminated. NCs acquired the conditional discrimination (S+ =70, S- =29). MTs were unable to respond differentially (S+ =42, S- =37). The findings indicate that the hippocampal system is essential in acquiring a conditional discrimination, even in a delay paradigm.
Fortier
Catherine Brawn
CB
Memory Disorders Research Center, Boston University School of Medicine, Boston, MA, USA. cbrawn@bu.edu
Disterhoft
John F
JF
Capozzi
Stephen
S
Kilduff
Patrick
P
Cronin-Golomb
Alice
A
McGlinchey
Regina E
RE
D000328:Adult; D000368:Aged; D000647:Amnesia / Q000503:physiopathology*; D000704:Analysis of Variance; D001245:Association Learning / Q000502:physiology*; D003215:Conditioning, Eyelid / Q000502:physiology; D004193:Discrimination Learning / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D008606:Mental Processes / Q000502:physiology; D008875:Middle Aged; D012193:Reversal Learning / Q000502:physiology; D013702:Temporal Lobe / Q000502:physiology*