Cognitive control beyond executive function

Any cognitive process, whether voluntary, goal-directed execution of complex tasks, spontaneous response to environmental stimuli, self-reflection, rumination, or mind-wandering requires the coordinated activity of a number of cognitive and related brain systems and networks. It involves the integration of currently relevant content and stimuli as well as the inhibition of irrelevant or distracting information. Neuroimaging results suggest a close relationship of task sets and cognitive states with specific patterns of brain activations and functional connectivity (FC) between individual brain areas and networks. We argue that specific patterns of FC enable the coupling of relevant brain systems into virtual work assemblies and facilitate the efficient flow and integration of information between them. Research on the control of cognitive processes has focused almost exclusively on conscious executive cognitive control (CC) for the purpose of efficient performance of cognitive tasks that require focused processing of information in accordance with provided rules. These studies revealed an important role of the fonto-parietal network (FPN) in CC. Despite intensive research, two questions remain unaddressed: (i) which cognitive and related brain systems are the source of modulation of other everyday cognitive processes and states that are not under the direct control of executive functions, and (ii) how is the modulation of FC that enables flexible transitions between cognitive and brain states implemented. Recent evidence suggests a strong link between disconnectivity of cortico-striato-thalamo-cortical (CSTC) circuit, cognitive impairment, and abnormal patterns of FC in a range of mental disorders. The extent of observed dysconnectivity correlates with symptom severity, predicts transition to psychosis and disease progression, while the specific pattern of dysconnectivity distinguishes between disorders. These results indicate that CSTC circuitry is a central pathway, a potential biomarker, and a promising therapeutic target in psychiatric disorders. In the proposed research project, we plan to use advanced analyses of concurrent acquisition of EEG and fMRI signals during the performance of a complex CC task, a natural viewing task, and at rest to test the hypotheses, (i) that, depending on the specific cognitive state and processes, brain networks other than the FPN serve as sources of CC, and (ii) that, regardless of the specific source of CC, the CSTC circuit plays a central role in the dynamic modulation of the brain FC, which is fundamental for the integration of brain function and cognitive processes. We will further apply the findings to understand the changes in FC and cognitive states in major depressive disorder (MDD). We will investigate whether the observed changes in FC in MDD reflect (i) structural changes in brain connectivity, (ii) changes in the relative influence of brain systems on cognition reflected in the imbalance between cognitive and related brain states, or (iii) dysfunction of CSTC circuitry in modulating brain FC. We will pay particular attention to the extent to which the observed changes and their causes are related to individual subgroups of patients identified by dimensions of neuro-behavioral variability. The proposed project introduces a new perspective on CC and the integration of cognitive processes that goes beyond current narrow conceptualizations. The findings will contribute to our understanding of the processes and mechanisms that enable integrated brain function in the context of executive CC as well as in the context of other cognitive processes that shape everyday experience. In addition, the results will expand our understanding of the neurocognitive mechanisms of depression, contribute to the identification of new biomarkers, and advance individualized medicine in psychiatry.