Functional MRI of human amygdala activity during Pavlovian fear conditioning: stimulus processing versus response expression.
Although laboratory animal studies have shown that the amygdala plays multiple roles in conditional fear, less is known about the human amygdala. Human subjects were trained in a Pavlovian fear conditioning paradigm during functional magnetic resonance imaging (fMRI). Brain activity maps correlated with reference waveforms representing the temporal pattern of visual conditional stimuli (CSs) and subject-derived autonomic responses were compared. Subjects receiving paired CS-shock presentations showed greater amygdala activity than subjects receiving unpaired CS-shock presentations when their brain activity was correlated with a waveform generated from their behavioral responses. Stimulus-based waveforms revealed learning differences in the visual cortex, but not in the amygdala. These data support the view that the amygdala is important for the expression of learned behavioral responses during Pavlovian fear conditioning.
Cheng
Dominic T
DT
Department of Psychology, University of Wisconsin-Milwaukee, 53201, USA.
Knight
David C
DC
Smith
Christine N
CN
Stein
Elliot A
EA
Helmstetter
Fred J
FJ
D000328:Adult; D000679:Amygdala / Q000502:physiology*; D001341:Autonomic Nervous System / Q000502:physiology; D003214:Conditioning, Classical / Q000502:physiology*; D004594:Electrophysiology; D005239:Fear / Q000502:physiology*; D005260:Female; D006801:Humans; D007858:Learning; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D014793:Visual Cortex / Q000502:physiology