Neural bases of emotional and motivational appraisals on processing of emotional visual scenes depending on spatial frequencies
Résumé
Visual processing of emotional stimuli critically depends on the cognitive appraisals
type such as identifying the self-emotional experience or emotional state of
others. Moreover, each particular affective appraisal may be driven by a specific
spatial frequency content in emotional stimuli. The present fMRI study aimed to
investigate the brain regions involved in the visual processing of emotional scenes
during two distinct affective appraisal tasks, one emotional based on the self-emotional
experience and one motivational based on the tendency to action. The relative
role of spatial frequency content of visual stimuli during each of these two
appraisal tasks was also explored by using scenes filtered in low spatial frequencies
(LSF) and high spatial frequencies (HSF). Results showed a greater activation
of the visual regions and amygdala in the motivational task compared to the emotional
task. Motivational task also induced specific activations of motor areas
(premotor cortex and supplementary motor area) and parietal regions (precuneus,
superior and inferior parietal lobules and angular gyrus) although required
motor response was similar in the two tasks. Parietal activations were particularly
obtained in appraisal of a tendency to approach a pleasant scene. These results
suggest that the identification of a tendency to action specifically involves motor
and navigation processes. Furthermore, cerebral activations in the motivational
task were mostly greater for HSF scenes compared to LSF scenes suggesting that
the tendency to action is mainly driven by the detailed information in scenes. In
the emotional task, only the visual regions showed a role of the spatial frequencies
with greater activity for HSF scenes (compared to LSF scenes) to evaluate the
unpleasant experience and for LSF scenes (compared to HSF scenes) to evaluate
the pleasant experience. Our study stresses distinct processing for identifying the
tendency to action and the self-emotional experience on emotional visual scenes,
and illustrates the flexible use of spatial frequency content in scenes depending
on the task demands.