The Instinctual Basis of Human Affect: Affective and fMRI Imaging of Laughter and Crying

Abstract

To investigate whether affective experience is linked to the neurodynamics of basic emotional systems, a novel mood-induction procedure was utilized to induce affective changes and observe the neural consequences. The internal motor imagery of laughter and crying (to evoke joy and sadness), along with the affectively neutral task of walk imagery, allowed evocation of affective states without the confounding effects of motor artifacts. Affective response scores (nine-point Likert scale) indicated that internal laughter significantly increased happiness and decreased sadness. Conversely, crying imagery significantly increased sadness and decreased happiness. Seven brain regions exhibited BOLD signal changes in the emotion tasks, which were not observed during the neutral walking task. These regions are the left basal ganglia, right putamen, insula, thalamus, and inferior occipital gyrus, and left and right caudate. These data suggest that there may be a shared neural system for activating affective responses.