Psychopathy is a personality disorder characterized by interpersonal manipulation and callousness, and reckless and impulsive antisocial behavior. It is often seen as a disorder in which profound ...emotional disturbances lead to antisocial behavior. A lack of fear in particular has been proposed as an etiologically salient factor. In this review, we employ a conceptual model in which fear is parsed into separate subcomponents. Important historical conceptualizations of psychopathy, the neuroscientific and empirical evidence for fear deficits in psychopathy are compared against this model. The empirical evidence is also subjected to a meta-analysis. We conclude that most studies have used the term "fear" generically, amassing different methods and levels of measurement under the umbrella term "fear." Unlike earlier claims that psychopathy is related to general fearlessness, we show there is evidence that psychopathic individuals have deficits in threat detection and responsivity, but that the evidence for reduced subjective experience of fear in psychopathy is far less compelling.
Application of magnetic or electrical stimulation to the motor cortex can result in a period of electromyography (EMG) silence in a tonically active peripheral muscle. This period of EMG silence is ...referred to as the silent period (SP). The duration of SP shows intersubject variability and reflects the integrity of cortical and corticospinal pathways. A non-invasive technique for assessing the duration of SP is the combination of Transcranial Magnetic Stimulation (TMS) with EMG. Utilizing TMS–EMG, several studies have reported on the shortening or lengthening of SP in neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, obsessive compulsive disorder, epilepsy, Parkinson's disease, and stroke. However, cortical, corticospinal and peripheral components are difficult to disentangle from EMG alone. Here, we use the multimodal neuroimaging technique of TMS–EMG combined with concurrent electroencephalography (EEG) recording to further examine the cortical origin of SP and the cortical oscillatory activity that underlies SP genesis. We demonstrate that the duration of SP is related to the temporal characteristics of the cortical reactivity and the power of delta to alpha oscillations in both local and remote areas ipsilateral and contralateral to the stimulation site, and beta oscillations locally. We illustrate that, compared to EMG, the EEG indices of the SP provide additional information about the brain dynamics and propose that the EEG measures of SP may be used in future clinical and research investigations to more precisely delineate the mechanisms underlying inhibitory impairments.
•We examined the EEG characteristics during the TMS-induced EMG silent period.•Silent period is related to EEG duration, peaks, and amplitude of N100 component.•Silent period may be mediated by local and distributed slow oscillations (1-12Hz).
The traditional distinction between exogenous and endogenous attentional control has recently been enriched with an additional mode of control, termed “selection history.” Recent findings have ...indicated, for instance, that previously rewarded or punished stimuli capture more attention than their physical attributes would predict. As such, the value that is associated with certain stimuli modulates attentional capture. This particular influence has also been shown for endogenous attention. Although recent leads have emerged, elucidating the influences of reward on exogenous and endogenous attention, it remains unclear to what extent exogenous attention is modulated by reward when endogenous attention is already deployed. We used a Posner cueing task in which exogenous and endogenous cues were presented to guide attention. Crucially, the exogenous cue also indicated the reward value. That is, the color of the exogenous cue indicated how much reward could be obtained on a given trial. The results showed main effects of endogenous
and
exogenous attention (i.e., speeded reaction times when either cue was valid, as compared to when it was invalid). Crucially, an interaction between exogenous cue validity and reward level was observed, indicating that reward-based associative-learning processes rapidly influence attentional capture, even when endogenous attention has been actively deployed.
Highlights • Repetitive transcranial magnetic stimulation (rTMS) can potentiate cortical inhibition in healthy human subjects. • Our findings break with convention that high frequency stimulation ...results in excitation whereas low frequency stimulation results in inhibition. • Our results suggest that longer sessions of rTMS with increased number of pulses are more effective in producing changes on cortical inhibition.
Psychopathic offenders show a persistent pattern of emotional unresponsivity to the often horrendous crimes they perpetrate. Recent studies have related psychopathy to alterations in white matter. ...Therefore, diffusion tensor imaging followed by tract-based spatial statistics (TBSS) analysis in 11 psychopathic offenders matched to 11 healthy controls was completed. Fractional anisotropy was calculated within each voxel and comparisons were made between groups using a permutation test. Any clusters of white matter voxels different between groups were submitted to probabilistic tractography. Significant differences in fractional anisotropy were found between psychopathic offenders and healthy controls in three main white matter clusters. These three clusters represented two major networks: an amygdalo-prefrontal network, and a striato-thalamo-frontal network. The interpersonal/affective component of the PCL-R correlated with white matter deficits in the orbitofrontal cortex and frontal pole whereas the antisocial component correlated with deficits in the striato-thalamo-frontal network. In addition to replicating earlier work concerning disruption of an amygdala-prefrontal network, we show for the first time that white matter integrity in a striato-thalamo-frontal network is disrupted in psychopathic offenders. The novelty of our findings lies in the two dissociable white matter networks that map directly onto the two major factors of psychopathy.
This study explores the intricate relationship between cognitive functioning and aggression, with a specific focus on individuals prone to reactive or proactive aggression. The purpose of the study ...was to identify important neuropsychological constructs and suitable tests for comprehending and addressing aggression.
An international panel of 32 forensic neuropsychology experts participated in this three-round Delphi study consisting of iterative online questionnaires. The experts rated the importance of constructs based on the Research Domain Criteria (RDoC) framework. Subsequently, they suggested tests that can be used to assess these constructs and rated their suitability.
The panel identified the RDoC domains Negative Valence Systems, Social Processes, Cognitive Systems and Positive Valence Systems as most important in understanding aggression. Notably, the results underscore the significance of Positive Valence Systems in proactive aggression and Negative Valence Systems in reactive aggression. The panel suggested a diverse array of 223 different tests, although they noted that not every RDoC construct can be effectively measured through a neuropsychological test. The added value of a multimodal assessment strategy is discussed.
This research advances our understanding of the RDoC constructs related to aggression and provides valuable insights for assessment strategies. Rather than suggesting a fixed set of tests, our study takes a flexible approach by presenting a top-3 list for each construct. This approach allows for tailored assessment to meet specific clinical or research needs. An important limitation is the predominantly Dutch composition of the expert panel, despite extensive efforts to diversify.
•The influence of affective touch on the rubber hand illusion (RHI) was examined.•Stroking velocity, stroking material and side of stimulation was manipulated.•Touch regarded as most pleasant (slow ...velocity on hairy skin) enhanced the RHI.•This suggests that emotional labelling of touch modulates body ownership.
Humans experience touch as pleasant when this occurs with a certain velocity (1–10cm/s). Affective, pleasant touch is thought to be mediated by a distinct neural pathway consisting of un-myelinated tactile afferents (C tactile fibers) that respond to stroking with a low velocity on the hairy skin. As pleasant touch provides additional information on bodily signals we hypothesized that, compared to regular touch, pleasant touch would have a stronger effect on body ownership as measured through induction of the rubber hand illusion (RHI).
Two experiments involving the RHI were conducted. In the first experiment, the effects of stroking velocity (3cm/s and 30cm/s) and stroking material (soft/rough) on the RHI were tested. In the second experiment, the effect of an additional stroking velocity (0.3cm/s) and side of stimulation (hairy and glabrous) was examined.
The first experiment showed that low velocity stroking in combination with a soft material was not only regarded as most pleasant but also resulted in an enhanced RHI on proprioceptive drift and temperature measurements. In the second experiment, we confirmed that stroking with a velocity of 3cm/s resulted in a larger RHI in terms of proprioceptive drift. In addition, compared to regular touch, pleasant touch of the hairy skin resulted in a larger proprioceptive drift, while similar stroking on the glabrous side of the skin did not induce a stronger effect of RHI on proprioceptive drift.
Our data suggest that pleasant touch modulates the body representation which is consistently reflected in a larger proprioceptive drift. Our data also suggest that C tactile fibers are likely to be involved in the modulation of body ownership.
Background Psychopathic offenders inevitably violate interpersonal norms and frequently resort to aggressive and criminal behaviour. The affective and cognitive deficits underlying these behaviours ...have been linked to abnormalities in functional interhemispheric connectivity. However, direct neurophysiological evidence for dysfunctional connectivity in psychopathic offenders is lacking. Methods We used transcranial magnetic stimulation combined with electroencephalography to examine interhemispheric connectivity in the dorsolateral and motor cortex in a sample of psychopathic offenders and healthy controls. We also measured intracortical inhibition and facilitation over the left and right motor cortex to investigate the effects of local cortical processes on interhemispheric connectivity. Results We enrolled 17 psychopathic offenders and 14 controls in our study. Global abnormalities in right to left functional connectivity were observed in psychopathic offenders compared with controls. Furthermore, in contrast to controls, psychopathic offenders showed increased intracortical inhibition in the right, but not the left, hemisphere. Limitations The relatively small sample size limited the sensitivity to show that the abnormalities in interhemispheric connectivity were specifically related to the dorsolateral prefrontal cortex in psychopathic offenders. Conclusion To our knowledge, this study provides the first neurophysiological evidence for abnormal interhemispheric connectivity in psychopathic offenders and may further our understanding of the disruptive antisocial behaviour of these offenders.
Two major etiological theories on psychopathy propose different mechanisms as to how emotional facial expressions are processed by individuals with elevated psychopathic traits. The Response ...Modulation Hypothesis (RMH) proposes that psychopathic individuals show emotional deficits as a consequence of attentional deployment, suggesting that emotional deficits are situation-specific. The Integrated Emotions System theory (IES) suggests that psychopathic individuals have a fundamental amygdala dysfunction which precludes adequate responsiveness to the distress of others.
Participants performed a visual search task in which they had to find a male target face among two female distractor faces. Top-down attentional set was manipulated by having participants either respond to the face's orientation, or its emotional expression.
When emotion was task-relevant, the low-scoring psychopathy group showed attentional capture by happy and fearful distractor faces, whereas the elevated group showed capture by fearful, but not happy distractor faces.
This study provides evidence for the RMH such that top-down attention influences the way emotional faces attract attention in individuals with elevated psychopathic traits. However, the different response patterns for happy and fearful faces suggest that top-down attention may not determine the processing of all types of emotional facial expressions in psychopathy.
•Here, two influential but opposing etiological theories of psychopathy are empirically tested.•We test emotional versus attentional deficits in psychopathy.•Top-down attention set influences emotion perception in psychopathy.•Different emotional expressions are not processed equally by psychopathic individuals.
An influential neurobiological model of personality is the Reinforcement Sensitivity Theory, which postulates how basic motivational systems (behavioral activation system BAS, behavioral inhibition ...system BIS) can help account for the development and expression of individual differences in personality. Earlier research has documented a link between psychopathic personality and the BIS/BAS scale (Carver & White, 1994), which was developed to measure the behavioral inhibition and activation systems. However, no studies have examined how latent BIS/BAS factors and the 4 empirically derived Psychopathy Checklist-Revised (PCL-R) psychopathy factors (Hare & Neumann, 2008) are associated across different cultures. In the current study, structural equation modeling was used to determine how the 4 PCL-R factors were able to predict BIS/BAS factors using 2 large independent samples of male offenders (North American N = 908; Swedish N = 242). The results were in line with theory and revealed a negative relationship between the PCL-R Affective factor and the BIS factor as well as positive relationships between the PCL-R Antisocial and Lifestyle factors with the BAS factor. Overall, the results of the current study provide evidence of cross-cultural generalizability for the associations between the PCL-R factors and the BIS-BAS factors. Taken together, the PCL-R psychopathy factors were able to account for meaningful variance in the BIS-BAS factors and further support a dimensional approach to understanding the psychopathy construct across cultures.
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