Brain States Encode both Perceived Emotion and the Physiological Response Induced by Visual Stimuli
Keith A. Bush1, Anthony A. Privratsky1, Jonathan B. Gardner1, Melissa J. Zielinski1, Clinton D. Kilts1; 1Brain Imaging Research Center, University of Arkansas for Medical Sciences, Little Rock, AR
Multivariate pattern analysis (MVPA) of functional magnetic resonance imaging (fMRI) has made critical strides in advancing our ability to characterize the functional anatomical encoding of affect in the human brain and to predict affective responses. Central to MVPA-based analysis is the brain state, a temporally-succinct whole-brain fMRI-derived pattern of neural activation, which acts as a unit of cognitive processing. However, if the brain state is the central unit of affective processing, then is must form a predictive link in the chain of conceptual causality within the modal model of emotion, commencing with stimulation and ending in a behavioral or physiological response. To test this central role, we used MVPA-based regression to characterize, via fMRI-derived brain states, both the continuously graded properties of valence and arousal of visual stimuli drawn from the International Affective Picture System (IAPS) as well as the co-occurring autonomic nervous system response measured via the skin conductance response (SCR) of (n=16) demographically diverse (across sex, race, age, and education) healthy subjects. We found that fMRI-derived brain states significantly predicted both the normatively scored valence and arousal properties of the IAPS stimuli as well as the induced SCR-based physiological response; alternatively, SCR significantly predicted only the arousal property. Moreover, brain state exhibited standardized product-moment prediction effect sizes more than four times greater than SCR, supporting its centrality in the modal model. Finally, anatomical encoding of the learned MVPA prediction function displayed remarkable agreement with the anatomical regions long-established in the fMRI-based emotion processing literature.
Topic Area: EMOTION & SOCIAL: Emotional responding