Proefschrift_Holstein

Chapter 7

y = 16

y = 6

y = - 6

cognition

action

reward

reward - cognition

reward - cognition - action cognition - action

anterior

posterior

Figure 7.1 Hypothesized interactions between corticostriatal circuits The red, green and blue vertical arrows between the cortical regions and the subparts of the striatum indicate connections between parts of the frontal cortex involved in reward anticipation (motivation, in red), task switching (cognition, in green) and response switching (action, in blue) and distinct regions in the striatum. The additional arrows in the lower panel indicate directional information flow between circuits, for example, from the reward circuit to the cognitive, and subsequently the action circuit (red arrows). Stimulation with cTBS over the aPFC, dlPFC and PMC is indicated by the red, green and blue thunderbolts, respectively. It is important to note that the arrows between the striatal regions indicate information flow and do not reflect anatomical connections. We aimed to investigate this functionally cascading architecture in humans by assessing the consequences of manipulating distinct prefrontal regions for reward motivation, cognition and action and associated signaling in distinct striatal subregions. To this end we used offline inhibitory TMS, (continuous theta burst stimulation; cTBS) (Huang et al., 2005), aiming to decrease neural signaling in three corticostriatal circuits (Ko et al., 2008; Volman et al., 2011; Wischnewski and Schutter, 2015), combined with fMRI to measure the impact of stimulation on task evoked activity in the striatum. Task-related processing was assessed using an established paradigm that we have used extensively to investigate reward anticipation, task switching and the effect of reward on task switching (Aarts et al., 2010; van Holstein et al., 2011; Aarts et al., 2014a; Aarts et al., 2015). The cortical stimulation sites were selected

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