Authors

Paradiso S. Johnson DL. Andreasen NC. O'Leary DS. Watkins GL.

Ponto LL. Hichwa RD.

 

Institution

Department of Psychiatry, University of Iowa College of Medicine, Iowa City, USA.

 

Title

Cerebral blood flow changes associated with attribution of emotional valence

to pleasant, unpleasant, and neutral visual stimuli in a PET study of normal

subjects.

 

Source

American Journal of Psychiatry. 156(10):1618-29, 1999 Oct.

 

Abstract

OBJECTIVE: To assist in the development of a model for the psychopathology of

emotions, the present study sought to identify the neural circuits associated

with the evaluation of visual stimuli for emotional valence. METHOD:

Seventeen healthy individuals were shown three sets of emotionally laden

pictures carrying pleasant, unpleasant, and neutral content. While subjects

evaluated the picture set for emotional valence, regional cerebral blood flow

was measured with the use of [15O] water positron emission tomography.

Subjective ratings of the emotional valence of the picture sets were

recorded. Data were analyzed by comparing the images acquired during the

neutral condition with the unpleasant and pleasant image sets and the

unpleasant and pleasant conditions with each other. RESULTS: Processing of

pleasant stimuli was associated with increased blood flow in the

dorsal-lateral, orbital, and medial frontal cortex relative to the unpleasant

condition and in the cingulate, precuneus, and visual cortex relative to the

neutral condition. Evaluation of unpleasant stimuli activated the amygdala,

visual cortex, and cerebellum relative to the pleasant condition and the

nucleus accumbens, precuneus, and visual cortex relative to the neutral

condition. CONCLUSIONS: Observing and assigning emotional value to unpleasant

stimuli produced activations in subcortical limbic regions, whereas

evaluation of pleasant stimuli produced activations in cortical limbic areas.

These findings are consistent with the notion of a subcortical and archaic

danger recognition system and a system detecting pleasantness in events and

situations that is phylogenetically younger, involving primarily the

prefrontal cortex.