Brain States That Encode Perceived Emotion Are Reproducible but Their Classification Accuracy Is Stimulus-Dependent

Abstract

The brain state hypothesis of image-induced affect processing, which posits that a one-to-one mapping exists between each image stimulus and its induced functional magnetic resonance imaging (fMRI)-derived neural activation pattern (i.e., brain state), has recently received support from several multivariate pattern analysis (MVPA) studies. Critically, however, classification accuracy differences across these studies, which largely share experimental designs and analyses, suggest that there exist one or more unaccounted sources of variance within MVPA studies of affect processing. To explore this possibility, we directly demonstrated strong inter-study correlations between image-induced affective brain states acquired 4 years apart on the same MRI scanner using near-identical methodology with studies differing only by the specific image stimuli and subjects. We subsequently developed a plausible explanation for inter-study differences in affective valence and arousal classification accuracies based on the spatial distribution of the perceived affective properties of the stimuli. Controlling for this distribution improved valence classification accuracy from 56% to 85% and arousal classification accuracy from 61% to 78%, which mirrored the full range of classification accuracy across studies within the existing literature. Finally, we validated the predictive fidelity of our image-related brain states according to an independent measurement, autonomic arousal, captured via skin conductance response (SCR). Brain states significantly but weakly (r = 0.08) predicted the SCRs that accompanied individual image stimulations. More importantly, the effect size of brain state predictions of SCR increased more than threefold (r = 0.25) when the stimulus set was restricted to those images having group-level significantly classifiable arousal properties.

Neural representations of social valence bias economic interpersonal choices

“…Alternatively, following previous work on affective priming and conflict (Dignath, Eder, Steinhauser, & Kiesel, 2020;Fritz & Dreisbach, 2013), adjectives could act as affective primes (Bush et al, 2018). Although we cannot completely rule out this possibility, previous results suggest otherwise.…”

Action-value processing underlies the role of the dorsal anterior cingulate cortex in performance monitoring during self-regulation of affect

“…Both experiments were control theoretic functional neuroimaging explorations of affect processing and regulation, which incorporated both unguided and real-time fMRI guided affect regulation tasks. Importantly, both experiments shared identical affect processing, affect regulation, and resting state task designs as well as identical task ordering; and, we have previously reported the relevant details of these studies' shared affect processing task demands 70 . Here, we elaborate the experiment design details that informed the present affect regulation analysis.…”

“…We achieved the first of these roles using 90 image stimuli that were computationally sampled from the International Affective Picture Set (IAPS) in order to maximize the subspace span of valence-arousal combinations in the resultant set of image stimuli. We have extensively reported our methodology and motivation for this sampling process 42,70 . We presented each of these image stimuli for 2 s followed by an inter-trial interval (ITI) uniformly randomly sampled from the range 2-6 s during which we presented a fixation cross.…”

“…We acquired all physiological signals at 2000 Hz. Specifically related to this study, we acquired galvanic skin response from the left hand; see Bush et al (2018) 70 for electrode placement details. We captured two separate measurements of facial electromyography (EMG): zygomaticus major (zEMG) and corrugator supercilii (cEMG).…”

“…We have previously reported in detail our methods for preprocessing and modeling galvanic skin response measures in past work 70 . In sum, we used the canonical skin conductance response function in conjunction with the beta-series method 79 to capture the temporally succinct physiological corollary of autonomic arousal associated with stimulus-induced affect processing 80 .…”