Universität zu Köln

Schmidgen, Julia ORCID: 0000-0002-3489-9718 (2025). Developmental Trajectories of Motor Networks in Health and Tourette Syndrome: Insights from Multimodal Neuroimaging. PhD thesis, Universität zu Köln.

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Abstract

Maturation of motor control represents a key aspect of brain development, characterized by a complex reorganization of cortical and subcortical networks that enable increasingly refined motor abilities. Deviations from these maturational trajectories are closely linked to the onset of various neurodevelopmental disorders. Within this framework, the present dissertation investigates the neural dynamics underlying motor control in typical development and identifies alterations of developmental patterns associated with Tourette syndrome (TS). Using a multimodal approach, including electroencephalography (EEG) with high temporal resolution, transcranial magnetic stimulation (TMS), and functional magnetic resonance imaging (fMRI) with high spatial resolution, this work provides a comprehensive insight into the organization and function of motor networks from early childhood through adolescence. To study processes related to motor preparation, sensorimotor integration, and the coordination of voluntary movement, participants performed cued motor tasks. Healthy development was characterized by a progressive improvement in motor performance, reflected in reduced reaction times and error rates. At the neural level, both EEG and fMRI provided converging evidence for the ongoing maturation of motor networks throughout childhood and adolescence. Motor preparation was associated with an age-related increase in supplementary motor area (SMA) recruitment, paralleled by a shift in the influence of the SMA on the ipsilateral primary motor cortex (M1) from inhibitory to excitatory. These results indicate a transition toward more proactive motor control strategies. Additionally, the inhibitory influence of the intraparietal sulcus (IPS) on SMA was associated with better motor performance, suggesting that maturing frontoparietal interactions play a regulatory role in refining motor output. Cortical activity related to preparatory motor control shifted from stronger ipsilateral to increasing contralateral motor area excitation, aligning with more efficient hemispheric specialization. Furthermore, fMRI revealed a linear increase in left parietal activity, particularly within visuomotor integration regions. Finally, TMS-EEG measurements demonstrated an age-related reduction in the N100 component, a marker of GABAB-related cortical inhibition, indicating refinement of inhibitory processes as the motor system matures. Children and adolescents with TS revealed comparable or even enhanced motor performance in cued tasks, despite showing deficits in blink suppression. Neurophysiological analyses revealed reduced theta-band connectivity and decreased network efficiency following informative cues, suggesting disrupted sensorimotor integration and perception-action binding. This reduction may reflect a compensatory attempt to minimize premature or involuntary motor output. During movement preparation and execution, data indicated a reorganization of motor networks, including increased connectivity within SMA and premotor regions. These adaptations occurred alongside overactivation of ipsilateral M1 and S1, with activation levels positively correlated with task accuracy, suggesting recruitment of additional motor resources to support performance. Further analysis revealed increased interhemispheric communication between left and right IPS, and a shift from inhibitory to excitatory influence of the IPS on premotor cortex (PMC). This may contribute to motor system hyperexcitability and atypical perception-action binding observed in TS. Finally, TS was characterized by reduced modulatory capacity of cortical inhibition during both motor preparation and execution, suggesting diminished flexibility in motor network regulation. These findings demonstrate that typical motor development is driven by increasing specialization and integration of frontoparietal and sensorimotor networks, supporting more efficient and lateralized motor function. In contrast, TS is marked by altered anticipatory processes and reduced inhibitory flexibility, counterbalanced by compensatory recruitment of alternative motor and sensory networks to maintain performance. This multimodal framework provides valuable insights into developmental mechanisms and highlights the dynamic interaction between dysfunction and adaptation in TS, offering direction for future therapeutic strategies.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Schmidgen, Julia UNSPECIFIED https://orcid.org/0000-0002-3489-9718 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-789755
Date:	2025
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Medicine > Psychiatrie und Psychotherapie > Psychiatrie und Psychotherapie des Kindes- und Jugendalters
Subjects:	Data processing Computer science Life sciences Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language Brain development; motor control maturation; motor networks English Neuroimaging English Neurodevelopmental disorders; Tourette Syndrome English
Date of oral exam:	5 August 2025
Referee:	Name Academic Title Bender, Stephan Prof. Dr. Nawrot, Martin Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/78975