Psychopathy can be assigned to four different categories, also called factors based on extensive empirical research (Fallon, 2013). These are the interpersonal factor, the affective factor, lack of empathy, and the non taking responsibility for one's own actions.
Psychopaths are very manipulative and are the best liars. In addition they can be very charming (Fallon, 2013).
Neuropsychology provides information of the brain areas that are possibly different in psychopaths in two ways. The first is to make a comparison among the behaviors and personality aspects of patients with brain damage and individuals with psychopatic traits. The second option is to give individuals with psychopatic traits neuropsychological tests (Glenn and Raine, 2014). neuropsychological tests rely upon the brain areas implicated in it.
Most psychopaths do not have evidence of brain damage, but their impairments are more slight. Patients having damage to their ventromedial prefrontal cortex exhibit signs that mimic psychopatic traits (Glenn and Raine, 2014, p. 87).
Miskovich et al. (2018) investigated local gyrification in male inmates with psychopathy as well as its association with the total factor and separate factor scores of the PCL-R. It was found that PCL-R scores were negatively correlated with measures in the right hemusphere in the mid-cingulate cortex and regions of the superior frontal gyrus and lateral parietal cortex. Factor 1 scores of the PCL-R were associated with less gyrification in the right mid-cingulate cortex, dorsomedial frontal cortex as well as higher gyrification in the occipital cortex. The second factor of the PCL-R did not give evidence of associations with altered gyrification in psychopatic individuals (Miskovich et al., 2018).
Tillem et al. (2019) found that psychopatic individuals had a more effective organized dorsal attention network as compared to non-psychopatic individuals. Furthermore, it was found that the amygdala, caudate nucleus, and hippocampus do not have an effective flow with cortical areas.
Resting state networks in the paralimbic areas, including the amygdala and insula were associated with psychopathy (Espinoza et al., 2019). There were nine functional domains associated with the PCL-R factor 1 scores and subcortical, auditory, sensorymotor, cerebellar, visual, the salience network, the default network, executive control, and attentional control networks (Espinoza et al., 2019).
Lapierre, Braun, and Hodgins (1994) gave criminal psychopaths and criminal non-psychopaths several neuropsychological tests to measure frontal lobe dysfunction. It was found that the tests that were associated wit behavioral disinhibition (such as rule-breaking behavior and errors of commission) and dysnosmia, which are indexes of ventral frontal dysfunction were impaired in the psychopaths. It is concluded by the authors that the findings can be explained by a specific orbitofrontal and/or ventromedial dysfunction in psychopatic individuals (Lapierre et al., 1994).
Lexico-semantic processing was investigated in criminal psychopaths while the underwent fMRI (Kiehl et al., 2004). The behavioral results showed that psychopatic participants displayed slower reaction times as compared to control subjects, when they evaluated abstract words. Furthermore, they also performed more worse than control participants in relation to the processing of pseudowords (Kiehl et al., 2004). The imaging findings found support for alternations in the right superior temporal gyrus in psychopatic individuals (Kiehl et al., 2004). Furthermore it was hypothesized that psychopatic individuals have impairments in temporal lobe functioning (Kiehl et al., 2004). In an earlier study Kiehl and associates (2001) investigated the neural correlates with fMRI while criminal psychopaths performed an affective memory task. Criminal psychopaths showed abnormalities in the limbic system while performing an affective memory task. Abnormalities were also found in the prefrontal cortex during the processing of affective stimuli. Regions that were especially implicated were the anterior and posterior cingulate cortex, the inferior frontal gyrus, the amygdala and hippocampal formation as well as the ventral striatum (Kiehl et al., 2001).
Psychopatic offenders were found to be impaired in nonverbal facial affect recognition, especially the recognition of disgust (Kosson, Suchy, Mayer, and Libby, 2002). This study did not find that psychopaths have impairments in the classification of fear and sadness. A finding that was not expected was that psychopatic individuals were better able to recognize angry facial expressions than the control subjects, Which was especially evident when they had to rely on lelf-hemisphere resources (responding a button with the right hand). It is suggested that psychopatic individuals might be characterized by enhanced attention to aggressive aspects, which might cause them to better recognize angry faces (Kosson et al., 2002). This study also investigated probable effects of abnormalities in hemispheric lateralization. It was found that the psychopaths were more reliant on their right hemisphere, which is in agreement with the probability that the impairment of psychopatic individuals in nonverbal processing might be due to either an impaired function in right-hemisphere emotion processing aspects or a diminished hemispheric asymmetry concerning the processing of emotion. It is concluded that psychopatic individuals are especially impaired in the recognition of disgust and a reliance on right-hemisphere resources and they might as well be better in recognizing anger in certain conditions (Kosson et al., 2002).
Birbaumer et al. (2005) used fMRI to investigate deficient fear conditioning in criminal psychopaths. The imaging analysis was performed while subjects performed a classic aversion differential delay task. Psychopatic individuals had different brain activations in more areas as compared to control subjects. Psychopathic individuals failed to exhibit important neural responses in fear conditioning as well as impaired responses at the behavioral level (Birbaumer et al., 2005).
Functional magnetic resonance imaging was applied to study the to dimensions of psychopathy and whether they show patterns of neural acivity that is in agreement with different underlying risk factors for the disorder (Sadeh, Spielberg, Heller, Herrington, Engels, Warren et al., 2013). Participants from the community scoring either high or low on psychopatic traits performed an emotion-word Stroop task while they underwent fMRI to measure selective attention. Both neurally and behaviorally, the dimension of fearless dominance was related to higher sensitivity to positive stimuli. Among subjects scoring high on psychopatic traits, there was found an impairment in the suppression of distractor words of positive valence, furthermore, there was found a moderation among activity to positive versus neutral stimuli in left SG/IPL as well as a cluster of the right SFG that was associated with errors of commission. It is suggested that this area was requitted in order to anhance the awareness due to inefficient responses and compensation for deficient attentional control for positively valenced words in the dimension of fearless dominance.
The second dimension, impulsive-antisociality was related to deficient attentional control as revealed by slower reaction times for both positive and negative stimuli as compared to neutral stimuli. It is suggested that persons scoring high on this dimension are highly sensitive to the emotional context of the task. The impulsive-antisociality dimension showed positive correlations in regions affected by emotional and motivational value, that were parts of the left amygdala, left posterior/agranular OFC and right agranular insula/OFC (Sadeh et al., 2013).
There was also an interaction found among the two dimensions, arguing for neural activation moderating selective attention in the presence of words of negative valence. More activation was found in subjects scoring high on both psychopathy dimensions, clusters of relevance were inferior and superior parietal lobules and areas associated with motor planning and response preparation, which included bilateral pre-/post-central gyri, and larger activity of the rostral anterior cingulate cortex, a area that is associated with cognitive control (Sadeh et al., 2013).
According to the authors, these findings suggest that subjects scoring high on both psychopathy dimensions did find words of negative valence more distracting and therefore did make use of more attentional resources in order to compensate for the distraction in performance. As a final result, the interaction of the two psychopathy dimensions exhibited a special association of activity in an area in the anterior, medial OFC (Sadeh et al., 2013).
Conteras-Rodriguez, Pujol, Batalla, Harrison, Bosque, Ibern-Regas et al. (2014) investigated neural processing of emotional faces in criminal psychopaths and healthy control subjects with an emotional face-matching task. The task was chosen in order to investigate the implicit processes of general emotion stimulation in criminal psychopaths, both in the positive and negative domain. During the task, the subjects were presented with a target face and two probe faces and participants had to match the probe that did express the same emotion as the target by pressing a button with either their left or right hand. During the task fMRI was used to disentangle the neural underpinnings (Contreras-Rodriguez et al., 2014).
The behavioral results of the face-matching task did not reveal any differences among the criminal psychopaths and the healthy control subjects. However, at the neural level group differences were found. The psychopatic individuals exhibited more activation in the neocortical regions that were involved in both visual and frontal cortices. Task induced decrements in functional connectivity were found among the amygdala, the visual cortex, and the prefrontal cortex. The present findings are interpreted by the authors as psychopatic individuals' equal task performance resulted in more involvement of the neocortex, and a lessened input to the limbic system (Contreras-Rodriguez et al., 2014).
Psychopatic individuals ans control subjects performed a visual oddball task while event-related potentials were recorded. It was found that psychopatic individuals exhibited a reduced P300 amplitude to target stimuli as compared to control subjects. This finding was present despite that there were no behavioral differences among the groups on the task (Kiehl, Hare, Liddle, and McDonald, 1999). The finding is suggested to be due to larger sensitivity of ERP measures concerning the group differences in information processing (Kiehl et al., 1999). Accordingly, this finding was thought to be in agreement with the hypothesis that the P300 in psychopatic individuals is the result of an impairment in the sustainment of attention or to the right allocation of resources to the task (Kiehl, et al., 1999). In the task that needs a decision response, they found also a larger frontocentral negativity ERP component. Furthermore, in the psychopatic individuals the P300 was to be found larger in amplitude over the right than over the left hemisphere. The authors conclude that their findings support the hypothesis that psychopathy is related to difficulties in the right modulation and allocation of attentional resources (Kiehl et al., 1999).
Fullam et al. (2009) investigated the neural responses during deception using fMRI in male participants with psychopatic traits as measured with the Psychopatc Personality Inventory (PPI). The response times in the lie condition were longer than in the thruth condition. Lying responses showed larger activation of the ventrolateral prefrontal cortex. Subscales of the PPI, coldheartedness, fearlessness, machiavellian egocentricity, social potency and stress immunity were associated with activity in brain areas that are both associated with deception as well as related processes. Thus, even in a healthy male group high on psychopatic traits differences were found (Fullam et al., 2009).
Individuals with psychopathy are famous for their grandiose sense of self-word while disregarding the wellbeing of other persons. A possible psychological aspect that might underly these traits is the relative consideration of "self" versus "others". The authors made use of a task based fMRI to investigate the neural activations while participants made personality trait judgments about themself and a familiar other in aduld male incarcerated psychopaths (Deminga, Philippic, Dargisa, Kiehl, and Koenings, 2018). While participants underwent fMRI they performed a task in which they had to make yes/no judgments for trait adjectives encompassing three conditions: self, mother, or case. Than a cueword (self, mother, or case) was presented with every adjective, which did signal the judgment of the participant about the target. The authors hypothesized that PCL-R Factor 1, consisting for example of egocentricity or lack of empathy would be associated with enhanced activity awhile self-judgment as compared to other-judgment in the cortical midline brain areas that are associated with social cognition. Contrary to hypothesis, no regions predicted this association. The factor 2 traits of psychopathy, such as impulsivity and irresponsibility showed diminished activation concerning self-judgment as compared to other-judgment in bilateral PCC as well as in the treatmenright TPJ (Deminga et al., 2018).
In conclusion, the authors suggest that the identified brain areas functioning might be disruptive for self-refective judgment in incarcerated psychopaths, for instance impulsivity. It is suggested that these results encompass a key part of socio-affective cognition that might be underlying the impulsive and irresponsible aspects of psychopathy (Deminga et al., 2018).
Motzkin, Newman, Kiehl, and Koenigs (2011) used diffusion tensor imaging and found that there was an attenuation in structural integrity whitin the richt uncinate fasiculus, which is the most important connection among the vmPFC and the anterior temporal lobe in psychopatic individuals. In addition, their fMRI results revealed a diminished functional connectivity among vmPFC and amygdala as well as among the vmPFC and medial parietal cortex in psychopatic individuals.
Structural and functional magnetic resonance imaging was used to investigate the neural correlates of reward and loss sensitivity in criminal psychopatic individuals and in criminal non-psychopatic individuals (Pujara, Motzkin, Newman, Kiehl, and Koenigs, 2013). During the scanning phase, the subjects performed a task that involved the passive gain or loss of money. In order to keep the participants' attention dedicated to the task, participants had to make a button press for the stimulus of which slot machine was the most likely to follow.
The imaging results revealed no group differences in criminal psychopatic individuals and criminal non-psychopatic individuals in the mean level of ventral striatum activity in the conditions of reward or loss. However, there was an important difference among the groups between activation of the ventral striatum in response to reward or loss concerning the severity of psychopathy (Pujara et al., 2013). The positive correlation found in criminal psychopaths associated with gain-loss ventral striatum activation appear to be due to a negative correlation with loss-neutral ventral striatum activation. Further it was found that the nucleus accumbens region of the right ventral striatum was also positively associated with the severity of psychopathy, but not in non-psychopaths. The authors believe that these findings are important indicators for an interaction among psychopathy and reward and loss sensitivity (Pujara et al., 2013).
fMRI scanning was used in participants from the community scoring either high or low on psychopatic traits (Marsh and Cardinale, 2014). It was investigated whether dysfunction of the amygdala would be associated to the willingness of individuals with high psychopatic traits to cause fear in other people.
The participants with high psychopatic traits did judge fear-evoking statements as more morally acceptable. Reduced amygdala activation was found during these judgments in individuals with high psychopatic traits as compared to participants scoring lower on psychopatic traits. Increased middle frontal gyrus activation was also found in individuals scoring high on psychopatic traits when they had to judge several aspects of emotional statements. Concerning the acceptability of frightening others was associated with activity in the amygdala and preceneus in participants scoring high on factor 1 psychopathy traits concerning emotional responsivity (Marsh and Cardinale, 2014).
Brain areas were investigated with the use of fMRI that were related in emotional processing in criminal psychopaths by using pictures of the IAPS (Muller et al. 2003). Pictures consisted either of neutral, positive, and negative load. During this task it was investigated how emotional content was related to different areas in the emotion-associated brain regions in criminal psychopaths. As compared to the control subjects the results of the experiment showed that there were different activations in the emotion-associated brain circuitry in criminal psychopaths, were some areas were to be found overactive and others underactive. It is hypothesized, based on these findings, that there is a dysregulation and impaired functional connectivity in criminal psychopaths. In this group, negative valenced emotions exhibited enhanced activity in right prefrontal areas as well as in the anterior cingulate cortex, and amygdala. In contrast, positive valenced emotions displayed enhanced activity in the left frontal gyrus (Muller et al., 2003). In addition, there was diminished activation found for negatively valenced pictures in the right subgenual cingulate and the right medial temporal gyrus, the left lobus paracentralis, the left dorsal cingulate cortex, as well as in the left parahippocampal gyrus. In contrast, positively valenced emotions exhibited diminished activation in the right medial frontal gyrus and the right medial temporal gyrus. According to the authors, psychopaths show abnormal activation in important cortical as well as subcortical emotion-associated brain areas, that might be responsible for their antagonistic ability. Furthermore, the authors suggest that their findings are in accordance with previous studies that found frontotemporal hyperactivation in psychopatic individuals (Muller et al., 2003). In the group of criminal psychopaths there was also an enhanced activation pattern found in the hippocampus. Based on the results of this experiment, the authors found evidence for an impaired interaction among top-down control which is associated with prefrontal areas as well as bottom-up signals from the limbic regions which might be the neurobiological cause in psychopaths (Muller et al., 2003) .
Deeley, Daly, Tunstall, Meyzey, Beer et al. (2006) tested wether psychopatic individuals would have a specific deficit in the processing of distressing stimuli. Event-related fMRI was performed to assess the neural responses in psychopatic individuals and control subjects while they were viewing emotional expressions of distress (fearful faces) and expression of positive emotion (happy faces). The results showed that psychopatic individuals had an abnormal response to fearful faces as compared to control subjects. Decreased activation was found in fusyform and extrastriate cortex. It is suggested that this might be accountable for a diminished autonomic responsiveness to signals of fear as well as the deficits in empathy (Deeley et al., 2006).
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