Functional MRI of human Pavlovian fear conditioning: patterns of activation as a function of learning.
fMRI was used to study human brain activity during Pavlovian fear conditioning. Subjects were exposed to lights that either signaled painful electrical stimulation (CS+), or that did not serve as a warning signal (CS-). Unique patterns of activation developed within anterior cingulate and visual cortices as learning progressed. Training with the CS+ increased active tissue volume and shifted the timing of peak fMRI signal toward CS onset within the anterior cingulate. Within the visual cortex, active tissue volume increased with repeated CS+ presentations, while cross-correlation between the functional time course and CS- presentations decreased. This study demonstrates plasticity of anterior cingulate and visual cortices as a function of learning, and implicates these regions as components of a functional circuit activated in human fear conditioning.
Knight
D C
DC
Department of Psychology, University of Wisconsin-Milwaukee, 53201, USA.
Smith
C N
CN
Stein
E A
EA
Helmstetter
F J
FJ
D000328:Adult; D001931:Brain Mapping; D003214:Conditioning, Classical / Q000502:physiology*; D003463:Cues; D004558:Electric Stimulation; D005239:Fear / Q000502:physiology*; D005260:Female; D006179:Gyrus Cinguli / Q000502:physiology*; D006801:Humans; D007858:Learning / Q000502:physiology*; D008027:Light; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology; D010775:Photic Stimulation; D014793:Visual Cortex / Q000502:physiology*