D. Erik Everhart

Up- and down-regulating facial disgust: Affective, vagal, sympathetic, and respiratory consequences

Relative to watching in a natural manner, people asked to suppress or exaggerate their facial response to a negative emotional stimulus experience greater activation of the sympathetic nervous system but report a similar subjective emotional experience. The present research extends prior research on response modulation in two important ways. First, discrete indicators of cardiac vagal and sympathetic control (respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP), respectively) were included as dependent measures along with interbeat interval (IBI) and skin conductance (EDR). Second, to help generalize results across response-focused modulation techniques, participants suppressed, exaggerated, or exerted no control over their responses while watching a disgust-eliciting film (for control purposes, a fourth group was asked to watch a neutral film naturally). Response modulation was associated with significantly decreased PEP (increased cardiac sympathetic control) relative to those in the natural-watch conditions. All participants evidenced increased EDR while watching the disgusting clip, but facial modulation did not produce EDR reactivity beyond that of watching the disgusting film naturally. Exaggerators experienced decreased IBI during modulation (perhaps due to increased muscle contraction) whereas all other groups showed increased IBI (i.e., the orienting response). Neither emotional experience nor facial modulation reliably impacted RSA, respiration rate, or inspiratory depth.

Resting RSA is associated with natural and self-regulated responses to negative emotional stimuli.

Resting respiratory sinus arrhythmia (RSA) was assessed among 111 adult participants. These individuals were then asked to watch a positive or negative affective film in either a natural manner or while exaggerating their facial response. Facial reactions to the film were video-recorded and subsequently rated in terms of facial affect. Participants also self-reported the valence of their emotional experience. Results from regression analyses revealed that persons with low resting RSA behaviorally evidenced a more negative facial response to the negative film under natural-watch conditions. Low RSA individuals were also less able to modulate (i.e., amplify) their facial response to the negative film. In terms of self-report measures, persons in the exaggerate condition reported more positive affect to the positive film than did those in the natural-watch condition. Results suggest that cardiac vagal control is inversely associated with negative facial expression but positively associated with facial regulation ability to negative stimuli.

Predicting facial valence to negative stimuli from resting RSA: Not a function of active emotion regulation

This research examined the relationship between emotional expressivity and respiratory sinus arrhythmia (RSA). A total of 94 healthy undergraduate participants watched a 2 minute movie that was either hedonically positive or negative and reported their emotional response to the film. Skin conductance, number of electrodermal responses (EDRs) and cardiac vagal control (respiratory sinus arrhythmia; RSA) were measured for the 2 minutes prior to and during the film. Facial expressions were videotaped during movie presentation and later rated in terms of valence. Regression analyses revealed that participants with higher baseline RSA levels expressed less negative (i.e., more neutral) facial affect to the negative film, but resting RSA did not predict facial valence to the positive film. In addition, RSA did not predict self-reported affect or sympathetic reactivity (EDRs), indicating that the pattern of facial responding exhibited by individuals with higher resting RSA was not the result of an active response modulation process (e.g., facial suppression or stimulus reappraisal). Although baseline RSA predicted RSA reactivity during the negative film, RSA reactivity did not predict facial valence. Results are discussed in terms of the relationship between cardiac vagal control, emotional expression, and self-regulation ability.

Healthy high-hostiles: reduced parasympathetic activity and decreased sympathovagal flexibility during negative emotional processing ☆

This study was designed to assess the physiological impact of processing neutral, positive, and negative emotional stimuli among a group of low- and high-hostile individuals. Advances were made by (1) measuring both reactivity and recovery to mood induction and (2) using Heart Rate Variability (HRV) to more specifically quantify sympathovagal (Low Frequency divided by High Frequency power, or LF/HF, within the HRV power spectrum) and parasympathetic arousal (Respiratory Sinus Arrhythmia; RSA) at the myocardium. In the present study, men and women were equally divided into low- (N=30) and high-hostile (N=30) groups based on their scores on the Cook–Medley Hostility Scale. Electrocardiogram data were collected before, during, and after being given the negative, positive, or neutral version of the Affective Auditory Verbal Learning Test (AAVL). Results indicate that high-hostiles had reduced parasympathetic activity relative to low-hostiles, as measured by RSA. Moreover, relative to low-hostiles, high-hostile participants evidenced reduced sympathovagal reactivity and recovery to the negative AAVL. Results are discussed in terms of their potential value in understanding risk factors for coronary heart disease.

Brain function with complex decision making using electroencephalography

A computer-administered assessment for decision making relevant to daily-living decisions, using the technique of complex decision making (CDM), has been previously developed and tested in our laboratory. The present study sought to identify unique patterns of brain activity in the alpha band associated with CDM. We recorded electroencephalogram (EEG) from 30 scalp sites, during a series of baseline, eyes open fixation tasks, and CDM tasks, in different contexts, in a group of 9 male and 7 female young healthy adults, aged 18 to 34. The decision making contexts, designed to simulate real-world, daily-living decisions, were about taking a bus, choosing a friend, job, medication, and participating in research. Electroencephalograms (EEGs) were divided into the frequency bands, alpha, beta, delta, theta, and gamma, though the primary focus of this paper is the alpha band. Analysis of mean EEG power spectra across the alpha bands - alpha1 (8-10 Hz), alpha2 (10-12 Hz), and alpha 3 (12-14 Hz) - showed significant decreases from baseline to the CDM task. In addition, we observed significant increases in delta, theta, beta, and gamma. There were also significant bivariate correlations between EEG spectra, mostly in low and mid alpha bands, behavioral performance on the CDM task, and scores on standardized measures of executive functioning, including the Trail-making Test and the Wisconsin Card Sorting Task. These results demonstrate how brain activity in complex decision making is distributed across alpha frequency bands and electrode regions and this activity relates to executive functioning.

BEHAVIORAL INHIBITION SYSTEM (BIS) STRENGTH AND TRAIT DOMINANCE ARE ASSOCIATED WITH AFFECTIVE RESPONSE AND PERSPECTIVE TAKING WHEN VIEWING DYADIC INTERACTIONS

The neurophysiology underlying the Behavioral Activation and Behavioral Inhibition Systems (BAS and BIS) and the impact of the strength of these systems on affective processing have received increased attention over the last 25 years. Specifically, left-frontal brain regions have been implicated in BAS strength as well as the experience of positive-approach affect (such as happiness). Conversely, BIS strength and negative-avoidance affect (such as fear) appear to be modulated by right-frontal brain regions. Taken together, it is not surprising that BAS and BIS strength have been associated with positive and negative affective biases, respectively, to emotional stimuli that do not involve extensive human interaction. The present investigation was designed to extend these findings by assessing the relationship between BAS and BIS strength on the perception of emotional interactions. Participants (n = 67) were shown four 2-min film clips that depict an individual exerting dominance over one or more other individuals. Each participant rated the clips with regard to valence, arousal, and dominance parameters, and then indicated the person(s) in the movie with whom they identified (i.e., the dominant individual or submissive individual[s]). Consistent with a priori hypotheses, persons identifying with the submissive character scored significantly higher on BIS sensitivity. BAS strength and BIS/BAS ratio, conversely, were not associated with character identification. Also as predicted, identification with the dominant movie character was associated with increased positive affect and feelings of dominance. Interestingly, although not hypothesized, trait dominance was also associated with character identification by virtue of being positively associated with BAS and PA and negatively associated with BIS and NA.

Low alpha power (7.5–9.5 Hz) changes during positive and negative affective learning

There is evidence that the positive and the negative word lists of the Affective Auditory Verbal Learning Test (AAVL) are useful with regard to mood induction. To date, however, changes in brain activation, as indicated by quantitative electroencephalographic recording, have not been examined. Thus, changes in low alpha power (7.5–9.5 Hz) were examined during and after completion of the positive or the negative learning list of the AAVL among 37 undergraduate men and women. Three primary findings from the study include the following: (1) Previously reported recall patterns were replicated; (2) participants who completed the negative list reported a significant decline in mood state at the end of the session; and (3) participants who completed the negative word list evidenced a significant reduction in low alpha power (in comparison with baseline) within the parietal regions. The findings noted above are seemingly counter to contemporary theories of mood regulation (i.e., asymmetrical changes in anterior activity, rather than changes in parietal regions). Although the AAVL may have limited utility as a tool for mood induction, it may serve as a functional tool for examination of the cerebral processes associated with affective verbal memory.

The influence of hostility on electroencephalographic activity and memory functioning during an affective memory task

OBJECTIVE The purpose of this study was to examine the neural correlates of emotional learning and hostility via the use of EEG and the Auditory Affective Verbal Learning Test (AAVL). METHODS The Cook-Medley Hostility Scale (CMHO) was used to identify right-handed men (N=16) and women (N=44) as low or high hostile. Participants were administered the positive and negative word lists of the AAVL lists, and were asked to recall the words during a 5-trial paradigm. EEG data were recorded from 19 scalp sites before and following learning trials; separate bandwidths of the EEG spectrum were analyzed. RESULTS As predicted, completion of the negative AAVL resulted in self-reported negative mood induction. Moreover, primacy and recency effects were demonstrated with the negative and positive versions of the AAVL, respectively. Unexpectedly, high hostiles demonstrated greater right versus left hemisphere high alpha power than low hostile counterparts. Low hostiles evidenced greater alpha power and low beta power than did high hostiles. CONCLUSIONS These results suggest differing patterns of hemispheric asymmetry and overall brain activity for low and high hostiles during emotional learning. SIGNIFICANCE The findings are important with regard to understanding the relationship between hostility, emotional learning, and associated neural systems.

Healthy high-hostiles evidence low-alpha power (7.5–9.5 Hz) changes during negative affective learning

The present experiment was designed to better understand the impact of positive and negative emotional processing among low- and high-hostile individuals. Based on previous research which found increased sympathovagal balance among low-hostiles to the negative version of the Affective Auditory Verbal Learning Test (AAVL), it was hypothesized that low-hostiles would experience increased cortical arousal to this stimulus whereas their high-hostile counterparts would not. As expected, low-hostiles experienced significantly reduced low-alpha power (7.5-9.5Hz) relative to high-hostiles during the presentation of the negative AAVL. In a replication of prior research, significant primacy and recency effects were noted for the negative and positive word lists, respectively. Results are discussed in terms of cerebral activation theory and the potential impact of emotional processing among high-hostile individuals and their likelihood to develop coronary heart disease.

Heart rate and fluency performance among high- and low-anxious men following autonomic stress.

Given the well-known associations between the right frontal lobe and negative effective states, as well as the involvement of the right posterior region in the modulation of autonomic nervous system arousal, anxiety is thought to be associated with relative right hemisphere activity (or decreased left hemisphere activity). However, recent evidence suggests that the left hemisphere predominantly modulates parasympathetic efferents, while the right hemisphere predominantly modulates sympathetic efferents of the autonomic nervous system. Thus, the left hemisphere should also play a role in anxiety, as anxiety is associated with decreased parasympathetic activity (increased heart rate). In order to investigate this hypothesis, the present experiment examined the influence of a well-known autonomic stressor (cold pressor) on heart rate (HR), and verbal and nonverbal fluency performance. Fifteen high level (HI) anxious and 15 low level (LO) anxious men completed verbal and nonverbal fluency measures after they were asked to place their left hand in ice water for 45 s. HI anxious subjects demonstrated opposing HR patterns during performance of the verbal (increased HR) and nonverbal (decreased HR) fluency tasks following cold pressor stimulation. In addition, HI anxious men generated fewer words per minute on the verbal fluency task than did LO anxious men. Although the data are supportive of functional right hemisphere activ ity among anxious individuals, the contribution of decreased left hemisphere activity (i.e., reduced parasympathetic activity and diminished verbal fluency performance) is also discussed.