Fear conditioning following unilateral temporal lobectomy: dissociation of conditioned startle potentiation and autonomic learning.
The present study investigated fear-potentiated startle and autonomic learning in brain-lesioned patients in a classical fear-conditioning paradigm. Startle blink and skin conductance responses of 30 patients who underwent unilateral temporal lobectomy because of drug-resistant epilepsy were compared with those of 32 healthy controls. As expected, temporal lobectomy patients showed a general impairment in fear conditioning relative to controls. This impairment did not differ with respect to the affected hemisphere. Moreover, while fear-conditioned startle potentiation in healthy controls was independent of contingency awareness, skin conductance discrimination was only observed for those participants who correctly recognized the stimulus contingencies. Patients who acquired a declarative memory of the contingencies also showed intact skin conductance discrimination but failed to exhibit fear-potentiated startle. The present findings support a two-levels-of-learning account of human fear conditioning and also demonstrate that the amygdala is crucially involved in fear learning.
Weike
Almut I
AI
Department of Psychology, University of Greifswald, 17487 Greifswald, Germany. weike@uni-greifswald.de
Hamm
Alfons O
AO
Schupp
Harald T
HT
Runge
Uwe
U
Schroeder
Henry W S
HW
Kessler
Christof
C
D000328:Adult; D000679:Amygdala / Q000503:physiopathology* / Q000601:surgery; D001767:Blinking; D016022:Case-Control Studies; D003214:Conditioning, Classical; D003463:Cues; D004192:Discrimination, Psychological; D004597:Electroshock; D004827:Epilepsy / Q000503:physiopathology* / Q000523:psychology* / Q000601:surgery; D005239:Fear; D005260:Female; D005712:Galvanic Skin Response; D006801:Humans; D007858:Learning; D008297:Male; D008568:Memory; D011184:Postoperative Period; D013216:Reflex, Startle; D013702:Temporal Lobe / Q000601:surgery*