Biomedical subjects

D Erik Everhart

Publications and source records attributed to D Erik Everhart.

13 recordsLinked to original sources

PubMed2006

Deception strategies in children: examination of forced choice recognition and verbal learning and memory techniques.

Thirty-five children ages 6-12 years were asked to complete two alternate forms of the Hopkins Verbal Learning Test-Revised (HVLT-R), once with the instruction to feign cognitive impairment and once instructed to do their best. They were also asked to complete the Test of Memory Malingering (TOMM). Regardless of condition, children performed comparably to adult norms on the TOMM, obtaining a score of 45 or above on Trial 2. Regarding the HVLT-R, differences emerged only when children were initially told to "do their best," followed by a subsequent trial in which they were told feign impairment. Within this group of participants, children demonstrated significantly lower levels of learning across trials and fewer words recalled in comparison to when they were instructed to do their best. In contrast, no reliable differences on the HVLT-R were observed among children who were initially told to feign impairment and subsequently told to do their best. These results suggest that the elicitation of "feigned" impairment within this age group on the HVLT-R requires the initial provision of an opportunity for optimal performance.

Age Factors↗

PubMed2006

Psychophysiological responses of adults who do not stutter while listening to stuttering.

The present study examined the psychophysiological responses of fluent listeners to stuttered speech. Specifically, skin conductance and heart rate changes were measured from adults who do not stutter while watching one-minute video speech samples of persons stutter read aloud. Fifteen adult participants observed three stuttered and three fluent speech samples, presented in random order with a two-minute interstimulus intervals. Results revealed that observing stuttered speech evoked a significant increase in skin conductance and a significant deceleration in heart rate relative to watching fluent speech samples. These findings suggest that listeners are physiologically aroused by stuttering and appear to maintain feelings of unpleasantness to stuttered speech. Further, deceleration in heart rate during stuttered samples also suggest that listeners may be paying more attention to the stuttered speech samples as compared to the fluent speech samples. We speculate that aberrant and anomalous stuttering behaviors probably simulate the mirror neuronal mechanism eliciting the emotional arousal associated within them. Such physiological arousal may provide the emotional genesis to the listener's negative stereotypical perceptions towards people who stutter.

Acoustic Stimulation↗

PubMed2006

Perception of emotional prosody: moving toward a model that incorporates sex-related differences.

The overall purpose of this article is to review the literature that addresses the theoretical models, neuroanatomical mechanisms, and sex-related differences in the perception of emotional prosody. Specifically, the article focuses on the right-hemisphere model of emotion processing as it pertains to the perception of emotional prosody. This article also reviews more recent research that implicates a role for the left hemisphere and subcortical structures in the perception of emotional prosody. The last major section of this article addresses sex-related differences and the potential influence of hormones on the perception of emotional prosody. The article concludes with a section that offers directions for future research.

Brain↗

PubMed2005

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.

Adult↗

PubMed2005

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.

Adolescent↗

PubMed2005

Brain lateralization of emotional processing: historical roots and a future incorporating "dominance".

This article provides a review of research on the hemispheric specialization in emotional processing during the past 40 years and the theoretical models derived from the conceptual analysis of these results. The publications reviewed here were collected to better appreciate the cortical lateralization of emotional perception (visual and auditory), expression (facial and prosodic), and experience. Four major models of emotional processing are discussed--the Right Hemisphere, Valence, Approach-Withdrawal, and Behavioral Inhibition System-Behavioral Activation System models. Observing the relative merits and limitations of these models, a new direction for exploration is offered. Specifically, to better appreciate the strength and direction (i.e., approach versus withdrawal) of experienced emotions, it is recommended that state "dominance" be evaluated in the context of asymmetrical activation of left-frontal (dominance) versus right-frontal (submission) brain regions.

Animals↗

PubMed2004

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.

Adaptation, Psychological↗

PubMed2004

Tone probe event-related potential differences during a face recognition task in prepubertal children and Turner Syndrome girls.

Hormones have been shown to play a role in both cerebral development and neurocognitive function. Turner Syndrome (TS) provides the opportunity to study the effect of the lack of estrogen on neurocognitive development. In this study, event-related potential (ERP) differences were examined among 12 TS girls, 20 prepubertal control girls, and 20 prepubertal control boys during a face recognition memory task. Stage of puberty was determined by Tanner Scale rating and hormonal assay. ERPs to pairs of auditory probe stimuli were recorded from eight scalp sites while participants performed a faced recognition memory (FRM) task. For the N2 component of the ERP (which has previously been associated with evaluation of stimulus information, categorization difficulty, and attention), control boys displayed greater right versus left hemisphere amplitude, control girls displayed greater left versus right hemisphere amplitude, and there was no amplitude asymmetry for TS girls. Further, control girls had greater left hemisphere N2 amplitude than control boys and TS girls, and greater right hemisphere N2 amplitude than TS girls. The results suggest more right hemisphere activation during face recognition in boys, while the opposite pattern was present in control girls. In contrast, TS girls displayed no asymmetry, indicative of more uniform involvement of the left and right hemispheres during face recognition. These findings are consistent with differences in cortical organization related to face recognition memory processing among prepubertal control boys, girls, and TS girls. They also support the notion that sex differences in cognitive function are present prior to pubertal onset, and that lack of endogenous sex hormones (e.g., estrogen) during prenatal/perinatal development (i.e., for TS girls) may influence brain organization and, in turn, neurocognitive processes that relate to face recognition.

Acoustic Stimulation↗

PubMed2004

Primacy and recency effects found using affective word lists.

This experiment tested hypotheses linking the right cerebral regulation of hostility and affective verbal learning. First, patterns of recall for positive, negative, and neutral affective list learning among high- and low-hostile individuals were examined. It was expected that low-hostiles would recall more items from the positive list and that high-hostiles would recall more words from the negative affective list. Also, independent of groups, it was expected that there would be a primacy effect for negative words and a recency effect for positive words. Exploratory analyses examined the relation between hostility and primacy and recency effects on the positive and negative word lists. High- and low-hostile participants (n = 65) completed the positive list learning task, the negative list learning task, or the neutral list learning task. Data analyses revealed no significant difference between the high- and low-hostile groups on the different affective lists. However, results of the present investigation reliably demonstrated the predicted primacy and recency effects. There was a primacy effect for the negative affective list and a recency effect for the positive affective list. These findings are consistent with previous research investigating the acquisition pattern of affective verbal learning.

Adult↗

PubMed2003

Healthy high-hostiles evidence low-alpha power (7.5-9.5Hz) 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.

Adolescent↗

PubMed2003

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.

Adolescent↗

PubMed2002

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 activity among anxious individuals, the contribution of decreased left hemisphere activity (i.e., reduced parasympathetic activity and diminished verbal fluency performance) is also discussed.

Adult↗

PubMed2002

Grip-strength, fatigue, and motor perseveration in anxious men without depression.

OBJECTIVE: To investigate the influence of anxiety without depression on functional motor asymmetry in adult men. Thus, left-and right-hand grip strength, fatigue across trials, and motor perseveration was examined among 60 right-handed men, half of whom had been classified as anxious without depression (HI, n = 30) and the other half as nonanxious without depression (LO, n = 30). BACKGROUND: There is substantial empirical support for the notion that individuals with negative affect experience relative right anterior activity. Moreover, previous studies using other groups of interest (e.g., depression and hostility) have found evidence of functional motor asymmetry that is supportive of relative right anterior activation during negative affect. Less is known about functional motor asymmetry among individuals that report anxiety without depression. METHOD: To obtain indices of perseveration, strength, and fatigue, HI and LO anxious subjects were asked to successively squeeze a hand dynamometer. Dependent measures (in kg) were derived from performance with the left and right hands across trials. RESULTS: In contrast to LO anxious subjects, HI anxious subjects did not demonstrate right-hand superiority for grip-strength. Moreover, significant positive correlations existed between grip strength and trait anxiety scores for LO anxious subjects, but not for HI anxious subjects. CONCLUSIONS: The data are partially supportive of differences in functional motor asymmetry between HI and LO anxious individuals. The findings are interpreted as supportive of relative right anterior activity (and possibly decreased left anterior activity) among individuals that report elevated levels of anxiety. Implications for relative right-hemisphere activity and decreased left anterior activity are discussed, and alternative explanations are introduced.

Adult↗