The neuro-oscillatory profiles of static and dynamic music-induced visual imagery.

Visual imagery, i.e., seeing in the absence of the corresponding retinal input, has been linked to visual and motor processing areas of the brain. Music listening provides an ideal vehicle for exploring the neural correlates of visual imagery because it has been shown to reliably induce a broad variety of content, ranging from abstract shapes to dynamic scenes. Forty-two participants listened with closed eyes to twenty-four excerpts of music, while a 15-channel EEG was recorded, and, after each excerpt, rated the extent to which they experienced static and dynamic visual imagery. Our results show both static and dynamic imagery to be associated with posterior alpha suppression (especially in lower alpha) early in the onset of music listening, while static imagery was associated with an additional alpha enhancement later in the listening experience. With regard to the beta band, our results demonstrate beta enhancement to static imagery, but first beta suppression before enhancement in response to dynamic imagery. We also observed a positive association, early in the listening experience, between gamma power and dynamic imagery ratings that was not present for static imagery ratings. Finally, we offer evidence that musical training may selectively drive effects found with respect to static and dynamic imagery and alpha, beta, and gamma band oscillations. Taken together, our results show the promise of using music listening as an effective stimulus for examining the neural correlates of visual imagery and its contents. Our study also highlights the relevance of future work seeking to study the temporal dynamics of music-induced visual imagery.

Cue-induced effects on decision-making distinguish subjects with gambling disorder from healthy controls.

While an increased impact of cues on decision-making has been associated with substance dependence, it is yet unclear whether this is also a phenotype of non-substance-related addictive disorders, such as gambling disorder (GD). To better understand the basic mechanisms of impaired decision-making in addiction, we investigated whether cue-induced changes in decision-making could distinguish GD from healthy control (HC) subjects. We expected that cue-induced changes in gamble acceptance and specifically in loss aversion would distinguish GD from HC subjects. Thirty GD subjects and 30 matched HC subjects completed a mixed gambles task where gambling and other emotional cues were shown in the background. We used machine learning to carve out the importance of cue dependency of decision-making and of loss aversion for distinguishing GD from HC subjects. Cross-validated classification yielded an area under the receiver operating curve (AUC-ROC) of 68.9% (p = .002). Applying the classifier to an independent sample yielded an AUC-ROC of 65.0% (p = .047). As expected, the classifier used cue-induced changes in gamble acceptance to distinguish GD from HC. Especially, increased gambling during the presentation of gambling cues characterized GD subjects. However, cue-induced changes in loss aversion were irrelevant for distinguishing GD from HC subjects. To our knowledge, this is the first study to investigate the classificatory power of addiction-relevant behavioral task parameters when distinguishing GD from HC subjects. The results indicate that cue-induced changes in decision-making are a characteristic feature of addictive disorders, independent of a substance of abuse.

Emotion effects within frontal alpha oscillation in a picture oddball paradigm.

In the current study we measured frontal alpha band oscillation in an oddball paradigm with emotional pictures as target stimuli. Within these emotional target pictures we varied valence and arousal separately. Irrespective of this emotional connotation, participants were asked to respond to the occurrence of any picture that deviates from the standard picture (a checkerboard). All stimuli were presented briefly and target stimuli were easily distinguishable from the standard stimulus based on mere perceptive features. Thus, the procedure reduces the probability that participants intentionally process or evaluate the emotional content of the pictures. With these incidental procedural conditions we yet observed a relative shift of alpha power to the right frontal site with increasing pleasantness of the pictures. Furthermore, frontal alpha band oscillation decreased with increasing picture arousal. These patterns were also evident when we controlled for valence and arousal of the pictures at the individual level. The results suggest that changes in frontal alpha band oscillation reflect reliable emotion correlates of incidental picture processing in the oddball paradigm.

Expertise in video game playing is associated with reduced valence-concordant emotional expressivity.

In carefully selected groups of video game playing (VGP) experts and nonexperts, we examined valence-concordant emotional expressivity. We measured electromyographic (EMG) activity over the corrugator supercilii muscle while participants viewed pleasant, neutral, and unpleasant pictures. Potential group differences concerning valence-concordant expressivity may arise from differences concerning the participants' emotional reactivity. To control for such differences, we concomitantly measured skin conductance response (SCR) and, in a separate affect misattribution procedure (AMP), valence transfer from the same set of stimuli. Importantly, we found attenuated valence-concordant EMG activity over the corrugator supercilii muscle in VGP experts compared to nonexperts, but no differences were evident concerning SCR or valence transfer in the AMP. The findings suggest that expertise in VGP is particularly associated with reduced valence-concordant emotional expressivity.

Embodied simulation as part of affective evaluation processes: task dependence of valence concordant EMG activity.

Drawing on recent findings, this study examines whether valence concordant electromyography (EMG) responses can be explained as an unconditional effect of mere stimulus processing or as somatosensory simulation driven by task-dependent processing strategies. While facial EMG over the Corrugator supercilii and the Zygomaticus major was measured, each participant performed two tasks with pictures of album covers. One task was an affective evaluation task and the other was to attribute the album covers to one of five decades. The Embodied Emotion Account predicts that valence concordant EMG is more likely to occur if the task necessitates a somatosensory simulation of the evaluative meaning of stimuli. Results support this prediction with regard to Corrugator supercilii in that valence concordant EMG activity was only present in the affective evaluation task but not in the non-evaluative task. Results for the Zygomaticus major were ambiguous. Our findings are in line with the view that EMG activity is an embodied part of the evaluation process and not a mere physical outcome.