In the Eye of the Storm : Connectivity studies on antisocial behavior and psychopathy

Abstract

This thesis consists of three sections. Section 1 is a proof of principle in which the functional contributions and mechanisms of interhemispheric connectivity will be addressed. The first chapter of Part 1 (§2.1) will examine the relationship between interhemispheric connectivity and personality features as measured per NEO-PI-R. In §2.2, the influence of alcohol on interhemispheric connectivity will be examined. This is of particular importance as more than 50% of all violent crimes are associated with alcohol (93) and up to 86% of all murders (94). The last chapter of part 1 (§2.3) is a methodological intermezzo in which we will examine the functional mechanisms associated with ISP by relating it to a second TMS measure of interhemispheric connectivity, IHI. The second part is the core of this thesis and it consists of 3 chapters in which TMS, EEG and DTI will be used to evaluate the integrity of brain networks in psychopathic offenders. In §3.1 we will examine whether psychopaths suffer from interhemispheric connectivity deficits by measuring their ISP and comparing it to that of healthy controls. Also, cortical inhibition and facilitation will be measured in the left and right motor cortex. In §3.2, an essential component of brain networks, white matter, will be assessed in psychopaths through diffusion tensor imaging (DTI). Using a tract based spatial statistics (TBSS) approach we explore white matter integrity throughout the brain in psychopathic offenders and compare them to healthy controls. Based on what was described in the previous pages an amygdalo-prefrontal network might be affected in addition to the mesolimbic reward pathway. §3.3 will test for the first time whether psychopathic offenders have inhibitory abnormalities in the DLPFC as compared to non-psychopathic individuals. To this end, we will use TMS in combination with EEG and assess LICI in the motor cortex and DLPFC. In addition, we will index working memory performance as it has been previously shown that psychopathic offenders may have impairments in this cognitive function. Part 3 endeavours into possible contributors to antisocial behavior. Here, in §4.1, we present the cerebellum as a key brain structure that is affected in many neuropsychiatric disorders including schizophrenia and autism. We will consider evidence for potential cerebellar involvement in disinhibited behavior. In §4.2, a rTMS manipulation of the cerebellum will be introduced to see whether alterations of cerebellar activity induce affective changes. To measure affective changes we use an affective pictorial Stroop task.