Cooperazione interemisferica nell'elaborazione di corpi emotivi

We used functional magnetic resonance imaging (fMRI) to investigate hemodynamic responses associated with interhemispheric cooperation in the context of an emotional stimulation. Fearful and happy bodies were used as stimuli of the well-known redundant target paradigm (RTP), a theoretically founded methodology to test interhemispheric interaction in visual perception, even in emotion domain. Nine healthy subjects and two hemispherectomized patients were part of the study. In healthy subjects, analyses of the contrast between the redundant fear condition and the two unilateral fear conditions led to an increased activation of amygdala, orbitofrontal cortex, intraparietal sulcus and precuneus, while a congruency effect was expressed in the significant activation of anterior cingulate cortex, basal ganglia, cerebellum and hippocampus for redundant congruent (fear) conditions, compared to incongruent ones (fear-happy). In patient DR, redundant presentations of fearful bodies, compared to unilateral ones, resulted in the significant activation of superior colliculus bilaterally, as well as of pulvinar and amygdala of the intact hemisphere; in addiction, significant activations of ventrolateral prefrontal cortex and area prostriata were observed. Coherently with healthy subjects, an emotional congruency-dependent activation of ACC was observed. Less informative results were obtained for patient SE, with a significant activation of pulvinar and extrastriate body area for redundant fear conditions. Overall results are consistent with the view on interhemispheric cooperation being a fundamental mechanism in processing emotional stimuli; furthermore, results obtained in hemispherectomized patients, especially DR, support the view of the involvement of superior colliculus in such an interhemispheric cooperation, particularly as far as non-conscious emotion perception is concerned.