Cognitive control and the prefrontal cortex: Functional measurements and effects of neuromodulation in healthy controls and a highly-impulsive risk population

• Applicants: Dr. Ann-Christine Ehlis, Ph.D.; Professor Dr. Andreas Jochen Fallgatter
• Subject Area: Biological Psychiatry ; Human Cognitive and Systems Neuroscience ; Personality Psychology, Clinical and Medical Psychology, Methodology
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 287036658

Human behaviour is based on decisions made in accordance with both internal goals and external environmental demands, the latter of which are largely perceived via sensory processing. Cognitive control is needed when goal-irrelevant automatic or prepotent information interferes with goal-relevant information in the selection of behaviour, i.e., when task-irrelevant stimulus features are associated with a response different from the one necessary for the current task instruction. This mismatch in stimulus-response mappings causes a conflict between incompatible response tendencies that hampers normal, goal-oriented behaviour. The mechanisms via which the cognitive control system overcomes this interference to achieve conflict resolution are still not completely understood. This project, therefore, aims at further elucidating the neural processes underlying cognitive control in humans and their modulability in both healthy subjects and neurocognitive risk populations. Thereby, cognitive control function will be examined after both externally induced conflict (see above) and internal conflict situations related to response errors. To this end, a conflict-inducing facial Stroop task as well as a modified Eriksen Flanker task commonly used to study error processing will be applied during simultaneous NIRS/EEG measurements. Moreover, a targeted modulation of regional cortical areas via transcranial magnetic stimulation (TMS) will be employed in terms of both facilitating and inhibitory protocols. Using this combination of methods, we plan to 1) experimentally confirm the dorsolateral prefrontal cortex (DLPFC) as a key structure within the neural network underlying conflict-adaptation not only following sensory interference, but also interference created by response errors; and 2) clarify the exact (neural) mechanisms via which the cognitive control system adapts information processing with the aim of conflict resolution. In a last step, we then plan to utilize the gained findings to selectively impact neural target structures in a healthy risk population putatively exhibiting cognitive control deficits (3). To this end, a facilitating TMS protocol will be used to modulate prefrontal functioning in highly-impulsive subjects, with the aim of improved conflict resolution via a thusly strengthened cognitive control system. For direct hypothesis testing, inhibitory TMS will conversely be used to temporarily disrupt normal frontal lobe function in a healthy control group, and effects on neural as well as behavioural correlates of conflict-adaptation will be determined. Using this bi-directional approach involving both inhibitory and facilitating challenge interventions in combination with neuroimaging methods, we will contribute important new data on the neural substrates and functional mechanisms underlying cognitive control in humans as well as their modulability in neuropsychiatric risk populations exhibiting prefrontal control deficits.

• DFG Programme: Research Grants