The goal of this dissertation was to delineate psychophysiological endophenotypes of social anxiety disorder. We conducted a unique two-generation family study, including patients with social... Show moreThe goal of this dissertation was to delineate psychophysiological endophenotypes of social anxiety disorder. We conducted a unique two-generation family study, including patients with social anxiety disorder, their partner and children, and their siblings with partner and children. This dissertation focused on EEG and heart rate measures during resting state, a social performance task and a social judgment paradigm. In the social performance task, participants watched and evaluated a speech of a female peer and then gave a speech in front of a video camera themselves. In the social judgment paradigm, participants received social acceptance or rejection feedback, after indicating their expectations about the upcoming feedback. This dissertation focused on three criteria for endophenotypes: association with SAD, co-segregation with SAD within families, and heritability. Delta-beta correlation during anticipation of a stressful social situation, and N1 and P3 amplitude in the social judgment paradigm are candidate endophenotypes of SAD. Show less
Top-down guidance of behavior in a complex and dynamically changing world is often based on information held in working memory. Such guidance serves to bias decision-making processes in directions... Show moreTop-down guidance of behavior in a complex and dynamically changing world is often based on information held in working memory. Such guidance serves to bias decision-making processes in directions consistent with externally set rules or internally maintained intentions. Orthogonal to this goal-driven guidance, decisions may be biased also by stimulus-driven factors, such as the automatic reactivation of episodic associations that accompanied the current stimulus in a previous instance. We investigated whether top-down and bottom-up processes account for variation in context based decision making as measured by the AX-CPT in a behavioral [1] and fMRI study [2]. Moreover, several behavioural studies have indicated that transiently induced positive affect modulates control processes in context-based decision making, generally leading to enhanced flexibility. Using ERPs in a classic AX-CPT, we studied the temporal dynamics of a positive affect induction on control processes in context-based decision making [3]. Additionally, we studied learning the associations between a situation, the response to it, and the outcome of that decision and the effect of basal ganglia modulations on this learning process by means of a Parkinson’s patient study. Studies [1] and [2] pointed out that in decisions with rapidly changing environmental demands, goal-driven preparation is often beneficial but may also hamper performance which can be overcome by applying increased control. Moreover, this top-down bias is regulated more efficiently when the specific stimulus is presented in the same context it was previously associated with, compared to when it is presented in a new and unusual context. Additionally, fMRI study shed light on the way these stimulus-driven performance changes may be represented in the brain. Study [3] showed that a positive affect induction influenced reactive and evaluative components of control (indexed by the N2 elicited by the target, and by the Error-Related Negativity elicited after incorrect responses) in an AX-CPT task, whereas cue-induced preparation and maintenance processes remained largely unaffected (as reflected in the P3b and the Contingent Negative Variation components of the ERP). The patient studies suggest that moderate dopaminergic medication and STN stimulation in Parkinson’s patients [chapter 5,6] both improve learning functions relying on caudate and putamen. However, the improvement induced by dopaminergic medication largely depended on individual patient characteristics. Show less
