Electrophysiological indicators of gesture perception.

Electroencephalography (EEG) activity in the mu frequency band (8-13 Hz) is suppressed during both gesture performance and observation. However, it is not clear if or how particular characteristics within the kinematic execution of gestures map onto dynamic changes in mu activity. Mapping the time course of gesture kinematics onto that of mu activity could help understand which aspects of gestures capture attention and aid in the classification of communicative intent. In this work, we test whether the timing of inflection points within gesture kinematics predicts the occurrence of oscillatory mu activity during passive gesture observation. The timing for salient features of performed gestures in video stimuli was determined by isolating inflection points in the hands' motion trajectories. Participants passively viewed the gesture videos while continuous EEG data was collected. We used wavelet analysis to extract mu oscillations at 11 Hz and at central electrodes and occipital electrodes. We used linear regression to test for associations between the timing of inflection points in motion trajectories and mu oscillations that generalized across gesture stimuli. Separately, we also tested whether inflection point occurrences evoked mu/alpha responses that generalized across participants. Across all gestures and inflection points, and pooled across participants, peaks in 11 Hz EEG waveforms were detected 465 and 535 ms after inflection points at occipital and central electrodes, respectively. A regression model showed that inflection points in the motion trajectories strongly predicted subsequent mu oscillations ([Formula: see text]<0.01); effects were weaker and non-significant for low (17 Hz) and high (21 Hz) beta activity. When segmented by inflection point occurrence rather than stimulus onset and testing participants as a random effect, inflection points evoked mu and beta activity from 308 to 364 ms at central electrodes, and broad activity from 226 to 800 ms at occipital electrodes. The results suggest that inflection points in gesture trajectories elicit coordinated activity in the visual and motor cortices, with prominent activity in the mu/alpha frequency band and extending into the beta frequency band. The time course of activity indicates that visual processing drives subsequent activity in the motor cortex during gesture processing, with a lag of approximately 80 ms.

Abnormal neural sensitivity to rewards as a candidate process of high depression risk in the FMR1 premutation: A pilot study.

The etiological heterogeneity of depression poses a challenge for prevention and intervention efforts. One solution is to map unique etiological pathways for subgroups defined by a singular risk factor. A relevant population for this approach is women who carry the premutation of the fragile X messenger ribonucleoprotein 1 (FMR1) gene, who are at high risk for adult-onset depression. This study explores a candidate neurophysiological marker of depression risk: reduced reward sensitivity, indexed by the reward positivity (RewP). The RewP has been linked to depression risk in the general population, but is unexplored within FMR1 premutation carriers. 16 women with the FMR1 premutation and a matched control group completed a simple guessing task while the electroencephalogram was recorded. Among premutation carriers, RewP difference score (win versus loss) was reduced. These preliminary finding suggest that the FMR1 premutation may confer increased risk for depression in part through abnormal neural sensitivity to rewards.

Error-monitoring across social and affective processing contexts.

The error-related negativity (ERN) is one of the most researched event-related potentials in the study of cognitive control, and it is thought to capture preconscious error-monitoring. ERN amplitude is known to be modulated by trait and state differences in affect, yet most ERN studies use 'cold' cognitive tasks that do not directly target affective processes involved in cognitive control. For example, speeded response-time tasks that elicit the ERN typically use neutral stimuli (e.g., letters, arrows), yet these paradigms are also flexible enough such that affective or social stimuli can readily be incorporated to target the role of affect in error-monitoring. In this project, the commonly-used arrow flanker task was modified to examine whether the expected behavioral and psychophysiological indices of error-monitoring would be observed using affective and social stimuli. Specifically, four different flanker tasks were administered using a within-subjects design with the following stimuli: arrows, neutral faces, unpleasant images, and pleasant images. Analyses indicated that the flanker tasks using arrows and faces elicited expected behavioral patterns (e.g., lower accuracy and slower reaction time on incongruent versus congruent trials) and ERN modulation by error versus correct trials. Although flanker tasks using unpleasant and pleasant stimuli also modulated the ERN, flanker effects on behavioral performance were not as consistent as the other tasks. Further, within incongruent trials, the ERN was larger when affective stimuli needed to be suppressed for a correct response. The correlations of the ERN and behavioral measures across tasks indicated some consistent individual differences in the ERN across tasks as well as substantial task-specific variances. This project lays the foundation for modifying classic error-monitoring tasks in a manner that may better target social and affective constructs that are of interest to clinical researchers.

Associations of mismatch negativity with psychotic symptoms and functioning transdiagnostically across psychotic disorders.

Mismatch negativity (MMN) amplitude has been widely shown to be diminished in schizophrenia and, more recently, in other psychotic disorders. Although there is considerable evidence linking MMN reduction to cognitive and functional deficits in schizophrenia, there is little evidence of associations with specific psychotic symptoms. Further, it is unclear if MMN reductions relate to specific symptoms, cognitive, and functional deficits transdiagnostically across different psychotic disorders. The present study examines MMN amplitude in a large cohort of cases diagnosed with psychotic disorders including schizophrenia and schizoaffective disorder (N = 116); bipolar disorder and major depressive disorder (N = 75); and other psychotic disorders (N = 25), as well as individuals with no psychotic disorder diagnoses (N = 248). Furthermore, we examined the association of MMN with symptoms, cognitive functioning, and real-world functioning to determine whether these relationships differ by diagnosis. Results showed that MMN amplitude was reduced in cases overall compared to never-psychotic individuals, with no differences between psychotic disorders. Furthermore, there were transdiagnostic associations of reduced duration MMN (MMN-D) with worse auditory hallucinations (r = .14) and disorganization (r = .14), frequency MMN (MMN-F) with real-word functioning (r = .20) and episodic memory (r = -.22), and both components with executive functioning (MMN-D: r = -.17; MMN-F: r = -.15). Our findings relating MMN reductions with cognitive and real-world functioning replicate earlier research in schizophrenia and extend these relationships to other psychotic disorders. Furthermore, our correlations with MMN-D are consistent with computational modeling research and theoretical proposals that view MMN reduction, cognitive dysfunction, and psychotic symptoms as reflecting underlying predictive coding deficits. However, differences in relationships with MMN-F suggest that additional work is warranted on this topic. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Variation in reward- and error-related neural measures attributable to age, gender, race, and ethnicity.

Event-related potentials (ERPs) have been widely applied to the study of individual differences in reward and error processing, including recent proposals of several ERPs as possible biomarkers of mental illness. A criterion for all biomarkers, however, is that they be generalizable across the relevant populations, something which has yet to be demonstrated for many commonly studied reward- and error-related ERPs. The aim of this study was to examine variation in reward and error-related ERPs across core demographic variables: age, gender, race, and ethnicity. Data was drawn from three studies with relatively large samples (N range 207-527). Results demonstrated that ERPs varied across the demographic variables of interest. Several examples include attenuated reward-related ERPs with increasing age, larger error-related ERPs for men than women, and larger ERPs to feedback after losses for individuals who identified as Hispanic/Latino. Overall, these analyses suggest systematic variation in ERPs that is attributable to core demographic variables, which could give rise to seemingly inconsistent results across studies to the extent that these sample characteristics differ. Future psychophysiological studies should include these analyses as standard practice and assess how these differences might exacerbate, mask, or confound relationships of interest.

The roles of valuation and reward processing in cognitive function and psychiatric disorders.

In neuroeconomics, valuation refers to the process of assigning values to states and actions on the basis of the animal's current representation of the environment, while reward processing corresponds to processing the feedback received from the environment to update the values of states and actions. In this article, we review the brain circuits associated with valuation and reward processing and argue that these are fundamental processes critical to many cognitive functions. Specifically, we focus on the role of valuation and reward processing in attention, memory, decision making, and learning. Next, the extant neuroimaging literature on a number of psychiatric disorders is reviewed (i.e., addiction, pathological gambling, schizophrenia, and mood disorders), and an argument is made that associated deficits in cognitive functions can be explained in terms of abnormal valuation and reward processing. The review concludes with the impact of this framework in clinical settings and prescriptions for future research, in particular with regard to the conversions of qualitatively different valuation systems into a system of common currency.

Individual differences in the time course of reward processing: Stage-specific links with depression and impulsivity.

Reward dysfunction has been implicated in a wide range of psychological disorders, including internalizing and externalizing psychopathology. Basic neuroscience research has shown that reward is a multistage process, yet it is unclear how specific stages relate to individual differences in reward sensitivity. The current study utilized event-related potentials elicited during a monetary incentive task to parse sub-stages within anticipatory and consummatory reward processing. Effects of depressive symptoms and trait impulsivity were examined at each sub-stage (N=92). Reward anticipation modulated neural activity across three sub-stages: cue detection (cue-P3), approach behavior (contingent negative variation, CNV), and outcome anticipation (stimulus preceding negativity). Reward delivery modulated activity across two sub-stages: initial evaluation (reward positivity, RewP), and allocation of attention (feedback-P3). Sensation seeking predicted faster reaction times, as well as cue-P3 and RewP amplitudes. Depression and lack of premeditation interacted to predict CNV and RewP amplitudes. Results demonstrate that individual differences in reward functioning are stage-specific.

Teasing apart the anticipatory and consummatory processing of monetary incentives: An event-related potential study of reward dynamics.

The monetary incentive delay (MID) task has been widely used in fMRI studies to investigate the neural networks involved in anticipatory and consummatory reward processing. Previous efforts to adapt the MID task for use with ERPs, however, have had limited success. Here, we sought to further decompose reward dynamics using a comprehensive set of anticipatory (cue-N2, cue-P3, contingent negative variation [CNV]) and consummatory ERPs (feedback negativity [FN], feedback P3 [fb-P3]). ERP data was recorded during adapted versions of the MID task across two experiments. Unlike previous studies, monetary incentive cues modulated the cue-N2, cue-P3, and CNV; however, cue-related ERPs and the CNV were uncorrelated with one another, indicating distinct anticipatory subprocesses. With regard to consummatory processing, FN amplitude primarily tracked outcome valence (reward vs. nonreward), whereas fb-P3 amplitude primarily tracked outcome salience (uncertain vs. certain). Independent modulation of the cue-P3 and fb-P3 was observed, indicating that these two P3 responses may uniquely capture the allocation of attention during anticipatory and consummatory reward processing, respectively. Overall, across two samples, consistent evidence of both anticipatory and consummatory ERP activity was observed on an adapted version of the MID paradigm, demonstrating for the first time how these ERP components may be integrated with one another to more fully characterize the time course of reward processing. This ERP-MID paradigm is well suited to parsing reward dynamics, and can be applied to both healthy and clinical populations.