Understanding the variability in the recruitment dynamics of cognitive control in rumination and insomnia

An intrinsic aspect of human cognition is its flexibility, enabling us to rapidly adapt our behavior in response to changing circumstances. This flexibility is thought to depend on specific cognitive control processes. The Dual Mechanisms of Control theory offers a framework for this flexibility and proposes that cognitive control reflects the dynamic interplay of proactive (i.e., sustained maintenance and updating of task-relevant information) and reactive (i.e., online interference monitoring and resolution) control. Although individuals with a high tendency to ruminate and individuals with insomnia disorder commonly report complaints of cognitive control functioning, behavioral and neurological evidence for these complaints remains surprisingly scarce and inconclusive (Chapter I). Using behavioral and electrophysiological measures, the studies of this dissertation showed that high trait rumination was not associated with a default shift towards more reactive control at the expense of proactive control (Chapter II). However, high trait rumination was primarily associated with an impaired performance to resolve proactive interference in a context requiring proactive control (Chapter III). Furthermore, using behavioral and electrophysiological measures, we observed that although individuals with insomnia disorder showed a comparable level of performance as good sleeper controls, they showed a reduced engagement of proactive control and also failed to engage reactive control to overcome invalid response tendencies (Chapter IV). Taken together, this dissertation provides empirical evidence for a decreased ability to flexibly adapt cognitive control in response to changing task contexts associated with high trait rumination and a disturbed balance in the engagement of cognitive control in insomnia. Finally, the broader significance and impact of the studies presented in this dissertation are discussed (Chapter V).status: publishe