Psychopathy is a complex personality disorder denned by a constellation of affective
and behavioral characteristics. There is accumulating behavioral evidence suggesting that the
condition is associated with impairments in affective, cognitive, and language functions.
However, relatively little is known regarding the neural systems underlying these
abnormalities. The present thesis is comprised of five experiments designed to elucidate and
characterize the abnormal functional architecture underlying these abnormalities in
psychopathic criminals. In Experiments 1 and 2, functional magnetic resonance imaging
(fMRI) was used to elucidate the neural systems underling abnormal semantic and affective
processes in these individuals. In Experiments 3, 4 and 5, event-related potentials (ERPs)
were used to characterize the temporal features of cognitive and language functions in
psychopaths.
The results from Experiment 1 revealed that compared to control participants,
psychopaths performed more poorly and failed to showed the appropriate neural
differentiation between abstract and concrete stimuli during a lexical decision task. These
deficits were located in the right anterior superior temporal gyrus.
The results from Experiment 2 indicated that psychopaths, relative to control
participants, showed less activation for processing affective stimuli than for neutral stimuli in
several neural regions, including the right amygdala/hippocampal formation, left
parahippocampal gyrus, ventral striatum, and in the anterior and posterior cingulate.
Psychopaths did show greater activation for processing affective than for neutral stimuli in
regions located outside the limbic system, including bilateral inferior frontal gyrus. These
latter data suggesting that psychopaths used different neural systems than did controls for
performing the task.
The results from Experiments 3 and 4 indicated that psychopathy is associated with
abnormalities in the P3 ERP component elicited by target stimuli during visual and auditory
oddball tasks. In addition, the psychopaths' ERPs to visual and auditory target stimuli were
characterized by large fronto-central negativities in the 350-600 millisecond time window.
These fronto-central ERP negativities are similar to those observed for patients with temporal
lobe damage.
In Experiment 5, using a standard sentence processing paradigm, no group
differences were observed between psychopaths and nonpsychopaths in the amplitude of the
N400 potential elicited by terminal words of sentences that were either congruent or
incongruent with the previous sentence context. These results indicate that the abnormal
fronto-central ERP negativities observed in previous studies of language function in
psychopaths are not related to processes involved in the generation of the N400.
Taken together, these data suggest that one of the cardinal abnormalities in
psychopathy is abnormal semantic processing of conceptually abstract information and
affective information and that these abnormalities are related to the function of neural circuits
in the anterior temporal lobes and lateral frontal cortex. / Arts, Faculty of / Psychology, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/10808 |
| Date | 05 1900 |
| Creators | Kiehl, Kent Anthony |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Format | 6867059 bytes, application/pdf |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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