Affective modulation of the startle reflex and the Reinforcement Sensitivity Theory of personality: The role of sensitivity to reward

Gender Differences in Prefrontal Cortex Response to Negative Emotional Stimuli in Drivers

BACKGROUND

Road safety improvement is a governmental priority due to driver-caused accidents. Driving style variation affects safety, with emotional regulation being pivotal. However, functional near-infrared spectroscopy (fNIRS) studies show inconsistent prefrontal cortex activity during emotion processing. This study examines prefrontal cortex response to negative emotional stimuli, particularly traffic accident images, across drivers diverse in age and gender.

METHOD

The study involved 118 healthy males (44.38 ± 12.98 years) and 84 females (38.89 ± 10.60 years). The Multidimensional Driving Style Inventory (MDSI) was used to assess driving behavior alongside fNIRS recordings. Participants viewed traffic accident and neutral images while prefrontal oxygenation was monitored.

RESULTS

Women rated traffic accidents (t-test = 2.43; p < 0.016) and neutral images (t-test = 2.19; p < 0.030) lower in valence than men. Arousal differences were significant for traffic accident images (t-test = -3.06; p < 0.002). correlational analysis found an inverse relationship between Dissociative scale scores and oxygenation (all p-values ≤ 0.013). Greater prefrontal oxygenation occurred with neutral images compared to traffic accidents. Left hemisphere differences (t-test = 3.23; p < 0.001) exceeded right hemisphere differences (t-test = 2.46; p < 0.015). Subgroup analysis showed male participants to be driving these disparities. Among adaptive drivers, significant oxygenation differences between neutral and accident images were evident in both hemispheres (left: t-test = 2.72, p < 0.009; right: t-test = 2.22, p < 0.030).

CONCLUSIONS

Male drivers with maladaptive driving styles, particularly dissociative ones, exhibit reduced prefrontal oxygenation when exposed to neutral and traffic accident images. This response was absent in female drivers, with no notable age-related differences.

Modulation of startle and heart rate responses by fear of physical activity in patients with heart failure and in healthy adults

Fear of physical activity (FoPA) has been suggested as a barrier to physical activity in patients with heart failure and might be associated with low adherence to exercise regimen despite medical guideline recommendations. The present study examined physiological indicators of FoPA by assessing startle modulation (via EMG at the orbicularis oculi muscle) and heart rate responses (derived from ECG) after affective priming with lexical stimuli of positive, neutral, and negative valence, as well as words related to physical activity as potentially phobic cues. After screening for FoPA in patients with heart failure and healthy adults, twenty participants each were assigned to one of three subsamples: a healthy control group and two cardiac patient groups scoring either low or high on FoPA. The high-FoPA group showed startle potentiation and more pronounced heart rate acceleration (than did controls) in the phobic prime condition, indicating defensive response mobilization. Among the patients, higher FoPA accounted for 30% of the startle potentiation by phobic priming, whereas general anxiety, depression, and disease severity were no significant predictors of startle modulation. These findings suggest that FoPA in patients with heart failure is associated with defensive responses on a physiological level that might be indicative of avoidance behavior, thereby contributing to low adherence to exercise regimen. Thus, FoPA presents a significant target for psychological interventions to foster physical activity in cardiac patients.

Eye blink and reward prediction error response in anorexia nervosa

BACKGROUND

Functional brain imaging has been used to study brain reward function and behavioral traits in anorexia nervosa (AN). Here we tested whether eye blink relates to behavior and brain imaging response as a method that is less costly and more accessible.

METHOD

We recruited 26 women with AN and 50 healthy matched controls. All underwent a reward-learning prediction error task during functional magnetic resonance imaging. In addition, eye blink was measured for spontaneous blink rate, baseline blink amplitude, and startle response to an auditory stimulus.

RESULTS

Baseline blink rate, amplitude and startle response were similar between groups. In AN, there were significant positive correlations between spontaneous blink rate and bulimia symptoms, and baseline blink amplitude and prediction error response in right-sided caudate, insula, and nucleus accumbens. Correlations between eye blink measures and body dissatisfaction or harm avoidance were no longer significant after multiple comparison adjustments.

DISCUSSION

This study provides evidence that measures of eye blink response can be related to brain prediction error response and eating disorder behavior in AN. The catecholamine dopamine contributes to both eye blink and prediction error response providing indirect evidence that it could be a neurobiological correlate that contributes to behaviors relevant to AN.

Latency to Reward Predicts Social Dominance in Rats: A Causal Role for the Dopaminergic Mesolimbic System

Reward signals encoded in the mesolimbic dopaminergic system guide approach/seeking behaviors to all varieties of life-supporting stimuli (rewards). Differences in dopamine (DA) levels have been found between dominant and submissive animals. However, it is still unclear whether these differences arise as a consequence of the rewarding nature of the acquisition of a dominant rank, or whether they preexist and favor dominance by promoting reward-seeking behavior. Given that acquisition of a social rank determines animals' priority access to resources, we hypothesized that differences in reward-seeking behavior might affect hierarchy establishment and that modulation of the dopaminergic system could affect the outcome of a social competition. We characterized reward-seeking behaviors based on rats' latency to get a palatable-reward when given temporary access to it. Subsequently, rats exhibiting short (SL) and long (LL) latency to get the rewards cohabitated for more than 2 weeks, in order to establish a stable hierarchy. We found that SL animals exhibited dominant behavior consistently in social competition tests [for palatable-rewards and two water competition tests (WCTs)] after hierarchy was established, indicating that individual latency to rewards predicted dominance. Moreover, because SL animals showed higher mesolimbic levels of DA than LL rats, we tested whether stimulation of mesolimbic DA neurons could affect the outcome of a social competition. Indeed, a combination of optical stimulation of mesolimbic DA neurons during individual training and during a social competition test for palatable rewards resulted in improved performance on this test.

Sex differences and personality in the modulation of the acoustic startle reflex

The modulation of the eyeblink component of the acoustic startle reflex (ASR) has been used to study human motivation, attention, and emotion towards affective stimuli of different valence. However, sex and individual differences in personality have been rather overlooked concerning the change in the ASR to brief affective sequences. In this study, we aimed to evaluate sex differences in the ASR, together with the influence of sensitivity to punishment (SP) and sensitivity to reward (SR) in the affective modulation of the ASR to pleasant and unpleasant pictures. We addressed this topic with a latent curve model (LCM) representing the change in the ASR of an extensive group of men (n = 166) and women (n = 109). There was a significant habituation of the ASR to the pleasant pictures, and a significant sensitization of the ASR to the unpleasant pictures. Both effects were higher and more variable for women than for men. There were in addition interactive and quadratic effects of SP and SR on the ASR to the pleasant and unpleasant pictures. Men and women with extreme scores in SP, and women with low scores in SR habituated faster to the pleasant stimuli. For men scoring low in SP, higher scores in SR related with an attenuated initial ASR to the unpleasant stimuli. Women with extreme scores in SP had a higher initial ASR to the unpleasant stimuli. There were remarkable asymmetries between men and women concerning personality effects on the change in the ASR to affective stimuli.

Is Evaluative Conditioning Moderated by Big Five Personality Traits?

Evaluative conditioning (EC), a change in liking of a stimulus due to its paired presentation with a positive or negative stimulus, is a key concept in attitude formation. The present article examines to what extent EC effects are moderated by Big Five personality. For this purpose, 567 participants completed an EC procedure and the Big Five Inventory. People high on neuroticism and agreeableness showed stronger EC effects than people low on those personality traits. In conclusion, attitude formation via EC depends in part on Big Five personality. This novel insight has important ramifications for EC research and personality research. As to EC research, the moderation by neuroticism suggests that EC effects intensify with an increased focus on valent stimuli. As to personality research, our findings reinforce the fundamental nature of the Big Five because they are evidentially able to moderate such basic learning phenomena as EC.

Evaluation of startle response and prepulse inhibition based on changes in the range of vertical pressure force of the feet on the ground: a preliminary study

The aim of the study was to evaluate the possibility of estimating a startle response and sensorimotor gating based on changes in the range of vertical pressure force of the feet on the ground during a dynamometric examination. The study encompassed 13 healthy and physically fit men (age: 23.3 ± 2.0 years; height: 178.0 ± 6.1 cm; and weight: 76.1 ± 9.0 kg). The inhibitory mechanisms of startle reflex were used as the measure of sensorimotor gating. It was triggered by a strong acoustic stimulus (106 dB SPL, 40 ms), which was preceded by a similar, weaker signal (80 dB SPL, 20 ms). Startle reflex was evaluated using a piezoelectric force platform. The results of the conducted study show that the range of vertical pressure force of the feet caused by the reaction to a strong acoustic stimulus is significantly smaller when this stimulus is preceded by a signal of lower intensity (prepulse). Such assessment is only possible with the participants' eyes open. The generalized startle response of a person may be estimated using a force platform, based on changes in the range of vertical pressure force of the feet on the ground, which are caused by unexpected acoustic stimuli. There is a strong indication that using a force platform to evaluate sensorimotor gating could be used as an alternative to electromyographic examinations.

Challenges of implementing a personalized mental task near-infrared spectroscopy brain-computer interface for a non-verbal young adult with motor impairments

PURPOSE

Near-infrared spectroscopy brain-computer interfaces (NIRS-BCIs) have been proposed as potential motor-free communication pathways. This paper documents the challenges of implementing an NIRS-BCI with a non-verbal, severely and congenitally impaired, but cognitively intact young adult.

METHODS

A 5-session personalized mental task NIRS-BCI training paradigm was invoked, whereby participant-specific mental tasks were selected either by the researcher or by the user, on the basis of prior performance or user preference.

RESULTS

Although the personalized mental task selection and training framework had been previously demonstrated with able-bodied participants, the participant was not able to exceed chance-level accuracies. Challenges to the acquisition of BCI control may have included disinclination to BCI training, structural or functional brain atypicalities, heightened emotional arousal and confounding haemodynamic patterns associated with novelty and reward processing.

CONCLUSIONS

Overall, we stress the necessity for further clinical NIRS-BCI research involving non-verbal individuals with severe motor impairments.

The behavioral approach system and augmenting/reducing in auditory event-related potentials during emotional visual stimulation

In the recent Reinforcement Sensitivity Theory Personality Questionnaire (RST-PQ, Corr and Cooper, 2016) the behavioral approach system (BAS) has been conceptualized as multidimensional in which facets of reward interest and reactivity, and goal-drive persistence, are separate from impulsivity. Aim of the present work was to highlight the predictive power of BAS and its facets in differentiating electrocortical responses by using an auditory augmenting/reducing event-related potential (ERP) paradigm during emotional visual stimulation. ERPs were recorded for 5 levels of intensity in 39 women. The RST-PQ was used to measure the total BAS (T-BAS) and its four facets of Goal-Drive Persistence (GDP), Reward Interest (RI), Reward Reactivity (RR), and Impulsivity (IMP). T-BAS and RI, and to a less extent GDP and RR, were significantly associated with higher N1/P2 amplitudes at central sites (C3, Cz, C4) across neutral, positive and negative slides. Similar, but less pronounced relations were found for GDP and RR, but this relation was lacking for Imp facet. In addition, N1/P2 slope at central sites was positively correlated with T-BAS, GDP, RI, RR, but not Imp. Indeed, T-BAS facets failed to maintain a significant correlation with N1/P2 slope, after controlling for T-BAS residual scores, indicating that T-BAS drives these significant correlations. LORETA analysis at 219ms (P2 wave) from tone onset revealed a significant activation of the right inferior parietal lobule (IPL, BA40) and left anterior cingulate gyrus (BA32) in high T-BAS compared to low T-BAS participants. Results are discussed within a revised RST framework differentiating reward components from impulsivity.

Assessment of Startle Response and Its Prepulse Inhibition Using Posturography: Pilot Study

Purpose. The aim of this study was to evaluate the possibility of using static posturography in the assessment of sensorimotor gating. Subjects and Methods. Fourteen subjects took part in the experiment. The inhibitory mechanisms of startle reflex were used as the measure of sensorimotor gating. It was evoked by a strong acoustic stimulus (106 dB SPL, 40 ms) which was preceded by the weaker similar signal (80 dB SPL, 20 ms). A stabilographic platform was used to measure sensorimotor gating. Results. Results of static posturography show that the postural sway caused by the reaction to a strong acoustic stimulus is significantly smaller when this stimulus is preceded by the signal of lower intensity (prepulse). Such assessment is only possible in eyes open conditions. Conclusions. Static posturography can be simple and effective method used for diagnosis of sensorimotor gating in humans.