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| Hauptseite > Publikationsdatenbank > Neural Underpinnings of Adaptive Control in Fronto-Subthalamic Networks. Dissertation |
| Hauptseite > Publikationsdatenbank > Neural Underpinnings of Adaptive Control in Fronto-Subthalamic Networks. Dissertation |
| Dissertation / PhD Thesis | FZJ-2026-02255 |
2025
Abstract: In an environment as complex and unpredictable as our human society, we cannot merely rely on hard-wired reflexes and short-term incentives for successful behavior. Instead, our brain uses cognitive control to derive expectations from current and prior information and adapts strategically to changing demands. Cognitive control involves interconnected processes that resist clear categorization, suggesting a shared core of control functions. Understanding this control architecture is crucial to understanding psychological and neuropsychiatric disorders that are linked to pathological control functions, as for example Parkinson’s disease. The aim of this thesis was to uncover the shared foundation that drives theoretically distinct aspects of control. Our focus was on the control required when a goal changes (response reprogramming) and the control employed when distractions occur (conflict resolution). Additionally, we assessed how these two aspects are modulated by expectations by varying their frequency of occurrence in a novel task. The integration of all these factors in one task allowed to test for interactions. Furthermore, the task processes were examined from different angles, which included neuroimaging data from healthy participants and electrophysiological data of people with Parkinson’s disease that received deep brain stimulation of the subthalamic nucleus (STN DBS; neuromodulation). In Chapter 2, we found behavioral evidence for a shared process behind reprogramming and conflict resolution in healthy participants. We predicted disproportionate performance decreases when these control demands coincided, reflecting limited resources for inhibition, flexibility or coordination, especially when they were unexpected. Indeed, we observed disproportionate error increases under these circumstances, suggesting a processing “bottleneck” that can be attenuated by anticipatory control (i.e., expectations). The same task was employed in another sample of healthy participants while recording control-related brain activity with functional magnetic resonance imaging (fMRI; Chapter 3). We focused on shared cortical network activations, particularly in relation to cingulo-opercular and fronto-parietal control networks, which are both implicated in reprogramming and conflict resolution. Behaviorally, we replicated the main pattern of an expectation-dependent bottleneck for error rates, which we observed in Chapter 2. On a neural level, fronto-parietal and cingulo-opercular activity was present in reprogramming as well as conflict resolution, while the shared engagement during both processes localized to the pre-supplementary motor area (pre-SMA), another key region in response control. Additionally, the right inferior frontal gyrus (IFG) was selectively activated when control demands coincided and were unexpected, which was linked to the error-related bottleneck. In Chapter 4, we explored the role of the STN in these control processes in people with Parkinson’s disease that received DBS of the STN. We recorded cortical electroencephalogram (EEG) and STN local field potentials (LFPs) to capture beta-band oscillatory signatures of inhibition and flexibility, which have been related to domain-general control. Behaviorally, active stimulation of the STN impaired control function during conflict, leading to increased errors. Moreover, reprogramming effects were generally attenuated as compared to a healthy population, indicating impaired motor preparation. Neurally, we observed both reprogramming and conflict-related beta signatures. Notably, elevated STN beta power increased error probability exclusively when reprogramming and conflict coincided, reflecting a putative bottleneck for flexible adaptations. Taken together, these findings are in line with a core involvement of beta dynamics and the STN in these control processes. In sum, our findings support the notion that control arises from core regions within fronto-subthalamic networks, and is governed by general mechanisms that employ inhibition and flexibility across modalities. In case control demands are particularly elevated or complex, adaptive capacities may be limited and require additional coordination, which could explain the observed “bottleneck” effect.
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