Psychopathy traits and reinforcement sensitivity theory: Prepulse inhibition and ERP responses

Interaction of Sensitivity, Emotions, and Motivations During Visual Perception

When an organism is exposed to environmental stimuli of varying intensity, the adaptive changes in the CNS can be explained by several conceptual provisions: the law of motivation-activation by Yerkes and Dodson, the laws of force and pessimal protective inhibition, and the theory of emotion activation. Later, reinforcement sensitivity theory was developed in the fields of psychology and psychophysics. At the same time, cortical prepulse inhibition (PPI), the prepulse inhibition of perceived stimulus intensity (PPIPSI), and the augmentation/reduction phenomenon were proposed in sensory neurophysiology, which expanded our understanding of consciousness. The aim of this study was to identify markers of levels of activity of cognitive processes under normal and in psychopathological conditions while amplifying the information stimulus. For this purpose, we changed the contrast level of reversible checkerboard patterns and mapped the visual evoked potentials (VEPs) in 19 monopolar channels among 52 healthy subjects and 39 patients with a mental illness without an active productive pathology. Their cognitive functions were assessed by presenting visual tests to assess invariant pattern recognition, short-term visual memory, and Gestalt perception. The personalities of the healthy subjects were assessed according to Cattell's 16-factor questionnaire, linking the data from neurophysiological and cognitive studies to factors Q4 (relaxation/tension) and C (emotional stability). According to the N70 and N150 VEP waves, the healthy subjects and the patients were divided into two groups. In some, there was a direct relationship between VEP amplitude and contrast intensity (21 patients and 29 healthy persons), while in the others, there was an inverse relationship, with a reduction in VEP amplitude (18 patients and 23 healthy persons). The relationship and mechanisms of subjects' cognitive abilities and personality traits are discussed based on the data acquired from the responses to information stimuli of varied intensity.

A multi-study investigation assessing the potential redundancy among the Dark Tetrad using a narrowband trait approach

We investigated the putative redundancy of the Dark Tetrad (specifically, Machiavellianism-psychopathy and sadism-psychopathy) through an examination of the differences between correlations with self-reported narrowband personality traits. In addition to measures of the Dark Tetrad, participants in four studies completed measures of various narrowband traits assessing general personality, aggression, impulsivity, Mimicry Deception Theory, and Reinforcement Sensitivity Theory. Results generally supported empirical distinctions between Machiavellianism and psychopathy, and between sadism and psychopathy. Machiavellianism significantly differed from psychopathy across correlations for nine of 10 traits (Study 1), 8 of 25 facets (Study 2), aggression (Study 3), 12 of 25 facets (Study 3), four of five facets (Study 4), impulsivity (Study 4), and five of six facets (Study 4). Sadism significantly differed from psychopathy across correlations with five of 10 traits (Study 1), eight of 25 facets (Study 2), reactive aggression (Study 3), 10 of 25 facets (Study 3), three of six facets (Study 4), impulsivity (Study 4), and three of six facets (Study 4). Our findings challenge the claims that Machiavellianism and psychopathy, as well as sadism and psychopathy, as currently measured, are redundant.

Mechanisms of False Alarm in Response to Fear Stimulus: An Event-Related Potential Study

Background and Objective

There is a paucity of research that has explored “False Alarm” mechanisms. In order to remedy this deficiency in knowledge, the present study used event-related potential (ERP) technology to reveal the mechanisms underlying False Alarm in response to fear stimuli.

Methods

This study selected snakes as experimental materials and the “oddball paradigm” was used to simulate the conditions of False Alarm. The mechanism underlying False Alarm was revealed by comparing cognitive processing similarities and differences between real snakes and toy snakes.

Results

Event-related potential findings demonstrated that there was no significant difference between N1 and P2 components induced by real and toy snakes in the early processing stage. Compared with toy snakes, real snakes induced smaller N2 amplitude, larger P3 amplitude, and a shorter P3 latency at the late processing stage. The results of brain topographic mapping analysis showed that the brain regions activated by a real or toy snake were basically the same within the time windows of 110–150 and 220–270 ms, respectively. In the time window of 300–360 and 400–500 ms, the degree of brain regions activation with a real snake was significantly greater than that induced by a toy snake.

Conclusion

False Alarm is caused by the brain’s inability to distinguish, in the early stage of cognitive processing, stimulus objects with similar appearances. When the brain is able to distinguish the differences between different stimulus objects in the late stage of cognitive processing, False Alarm disappears.

Instantaneous radiated power of brain activity: application to prepulse inhibition and facilitation for body dysmorphic disorder

Background

Global measures of neuronal activity embrace the advantage of a univariate, holistic and unique description of brain activity, reducing the spatial dimensions of electroencephalography (EEG) analysis at the cost of lower precision in localizing effects. In this work, the instantaneous radiated power (IRP) is proposed as a new whole-brain descriptor, reflecting the cortical activity from an exclusively electromagnetic perspective. Considering that the brain consists of multiple elementary dipoles, the whole-brain IRP takes into account the radiational contribution of all cortical sources. Unlike conventional EEG analyses that evaluate a large number of scalp or source locations, IRP reflects a whole-brain, event-related measure and forces the analysis to focus on a single time-series, thus efficiently reducing the EEG spatial dimensions and multiple comparisons.

Results

To apply the developed methodology in real EEG data, two groups (25 controls vs 30 body dysmorphic disorder, BDD, patients) were matched for age and sex and tested in a prepulse inhibition (PPI) and facilitation (PPF) paradigm. Two global brain descriptors were extracted for between-groups and between-conditions comparison purposes, namely the global field power (GFP) and the whole-brain IRP. Results showed that IRP can replicate the expected condition differences (with PPF being greater than PPI responses), exhibiting also reduced levels in BDD compared to control group overall. There were also similar outcomes using GFP and IRP, suggesting consistency between the two measures. Finally, regression analysis showed that the PPI-related IRP (during N100 time-window) is negatively correlated with BDD psychometric scores.

Conclusions

Investigating the brain activity with IRP significantly reduces the data dimensionality, giving insights about global brain synchronization and strength. We conclude that IRP can replicate the existing evidence regarding sensorimotor gating effects, revealing also group electrophysiological alterations. Finally, electrophysiological IRP responses exhibited correlations with BDD psychometrics, potentially useful as supplementary tool in BDD symptomatology.

Cocaine Increases Sensorimotor Gating and is Related to Psychopathy

OBJECTIVE

Prepulse inhibition regulates sensorimotor gating and is a marker of vulnerability to certain disorders. We compared prepulse inhibition, psychopathy, and sensitivity to punishment and reward in patients with cocaine-related disorder without psychiatric comorbidities and a control group.

METHODS

This was an observational study of a sample of 22 male cases with cocaine-related disorder and 22 healthy male controls. We used the Psychiatric Research Interview for Substance and Mental Disorders and Mini International Neuropsychiatric Interview; the Sensitivity to Punishment and Sensitivity to Reward Questionnaire; and the Levenson Self-Report Psychopathy Scale and Hare Psychopathy Checklist-Revised. Prepulse inhibition was evaluated at 30, 60, and 120 ms.

RESULTS

Cocaine-related disorder group had a higher overall score (t = 12.556, p = .001) and primary psychopathy score (t = 3.750, p = .001) on Levenson Self-Report Psychopathy Scale, a higher score on both Hare Psychopathy Checklist-Revised factors, sensitivity to rewards (t = 3.076, p = .005) and prepulse inhibition at 30 ms (t = 2.859, p = .008).

CONCLUSIONS

Cocaine use in patients without psychiatric comorbidities seems to increase sensorimotor gating. Therefore, these patients likely have an increased sensitivity to rewards, causing them to focus more on cocaine-boosting stimuli, thus explaining the psychopathic traits of these individuals.

Reward sensitivity, affective neuroscience personality, symptoms of attention-deficit/hyperactivity disorder, and TPH2-703G/T (rs4570625) genotype

OBJECTIVE

Reward sensitivity is an increasingly used construct in psychiatry, yet its possible inner structure and relationship with other affective variables are not well known.

METHODS

A reward sensitivity measurement scale was constructed on the basis of large item pool collected from birth cohort representative samples (the Estonian Children Personality Behaviour and Health Study; original n = 1238). Affective Neuroscience Personality Scale (ANPS) and the Adult Attention deficit hyperactivity disorder (ADHD) Self-Report Scale (ASRS) were administered in young adulthood. A variant (rs4570625) of the gene encoding tryptophan hydroxylase 2 (TPH2) that is responsible for the synthesis of central serotonin was genotyped.

RESULTS

Reward sensitivity consisted of two orthogonal components, operationally defined as Openness to Rewards and Insatiability by Reward, that respectively characterise the striving towards multiple rewards and the strong pursuit and fixation to a particular reward. While SEEKING and PLAY (and to lower extent CARE) of the ANPS co-varied with Openness to Rewards, FEAR, SADNESS, and ANGER were related to Insatiability by Reward. The total score of ASRS was moderately correlated with Insatiability by Reward, while the association with Openness to Rewards was negligible. However, ASRS Inattention had some negative relationship with the Social Experience facet of Openness to Rewards. The T/T homozygotes for the TPH2 promoter polymorphism had lower Insatiability by Reward but not Openness to Rewards.

CONCLUSIONS

Behaviours sensitive to rewards are separable to the components of variability and fixation, and these components are differentially related to affective aspects of personality, attention, and hyperactivity as well as to TPH2 genotype.

EEG gamma activity to emotional movies in individuals with high traits of primary "successful" psychopathy

This study aimed to investigate emotional alterations in a community sample with primary psychopathic traits. Sixty males selected from a larger sample and divided in two groups, High (HP) and Low (LP) primary Psychopathy, watched 15 validated emotional movies divided in five categories (Erotic, Neutral, Fear, and the new Scenery and Compassion). Subjective responses and cortical activity in the EEG Gamma band (30-49 Hz) were recorded. Concerning self-reports, HP participants felt less anxious and anguished in response to Fear clips and less sad, touched and anguished by Compassion excerpts. Negative clips induced larger EEG Gamma activity in both groups compared to neutral and erotic movies, but Gamma activity to Fear movies was reduced in HP. This group showed also a small cortical response to positive Scenery movies, at the level of the Neutral ones. Source analysis showed in HP participants a reduced cortical activation to Fear in a large brain network, comprising the right prefrontal and temporal cortices and bilateral inferior parietal cortex. Results showed that primary psychopathy, in addition to the impaired response to Fear, was associated with a reduced response also to other specific categories of emotional stimuli, suggesting an altered affect on a broader scale.