Non-invasive neuromodulation of the right temporoparietal junction using theta-burst stimulation in functional neurological disorder

Background. Agency, a sense of control over one’s actions and outcomes, is crucial for recovery from depressive symptoms. However, the mechanisms that enhance agency in individuals with depressive symptoms remain poorly understood. This study endeavors to elucidate these fundamental processes. Materials and Methods. We recruited 52 participants exhibiting depressive symptoms to participate in a novel Judgment of Agency (JoA) task. This task was structured with a 3 (effort: high load, medium load, low load) × 2 (outcome: win, miss) within‐subject design to assess the impact of effort and outcome valence on agency. Throughout the task, we utilized functional near‐infrared spectroscopy (fNIRS) to explore the neural mechanisms underlying agency. Furthermore, we conducted a randomized, sham‐controlled, pre–post‐test trial involving intermittent theta‐burst stimulation (iTBS) targeted at the left dorsolateral prefrontal cortex (DLPFC) to investigate its potential to enhance agency. Participants were randomly allocated to either an active iTBS group or a sham group, with each receiving a single session of stimulation (600 pulses). The JoA task was conducted both before and after the stimulation. Results. Effort significantly influenced agency in individuals with depressive symptoms, with this effect being moderated by the outcomes’ valences. Agency was positively correlated with self‐efficacy (r = 0.28, P < 0.05) when goals were achieved with effort, and with anxiety severity (r = 0.29, P < 0.05) when goals were not achieved. Additionally, it was associated with the activation of several frontal brain regions (all P values < 0.01), including the left DLPFC, right premotor and supplementary motor areas, and the left inferior frontal gyrus (IFG). Application of iTBS over the left DLPFC significantly enhanced self‐attributed agency, particularly when the outcomes were achieved under conditions of low‐load effort. Conclusions. Our study highlights the critical role of effort in enhancing agency for individuals with depressive symptoms, with iTBS applied to the left DLPFC showing potential to enhance agency postgoal achievement. Moreover, the activation of the left IFG and the presence of anxiety are associated with maladaptive self‐attributed agency, offering potential targets for therapeutic intervention.

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Altered brain network dynamics in motor functional neurological disorders: The role of the right temporo-parietal junction.

Weber,

Bühler,

Bolton

et al. 2024

Preprint

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Functional neurological disorders’ (FND) neuropathophysiology has been described as multi-network disturbances including aberrancies in the agency network highlighting the role of the right temporo-parietal junction (rTPJ). Refining the relevance of the rTPJ. we applied a co-activation pattern (CAP) based approach using the rTPJ as seed in 58 patients with motor FND compared to 58 age- and sex-matched healthy controls. Firstly, CAPs were derived from HC to identify functional alteration in the rTPJ network in FND patients. Secondly, motor subgroup characteristics in patients were examined using CAPs derived from the patient group. Compared to HC, patients were found to enter less frequently a state characterized by salience network and default mode network (DMN) co-activation along with executive control and somatomotor networks co-deactivation. Additionally, patients entered more often a state depicted by somatomotor-salience co-activation and DMN co-deactivation. Comparing motor subgroups, patients with functional weakness remained longer in a state characterised by attention network co-activation and DMN co-deactivation compared to patients with no functional weakness. FND patients overall exhibited a reduced coupling of the DMN and an increased coupling of the somatomotor network with the rTPJ compared to controls. Patient subgroups differed regarding coupling between rTPJ to attention network and DMN. rTPJ dynamic network alterations might reflect hampered flexibility in brain state switching and altered self-referential processes linked to impaired motor planning and execution, which seems to also differ between symptom types, indicating a potential phenotypic biomarker.

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Non-invasive neuromodulation of the right temporoparietal junction using theta-burst stimulation in functional neurological disorder

Cited by 3 publications

References 41 publications

BOLD signal variability as potential new biomarker of functional neurological disorders

BOLD signal variability as potential new biomarker of functional neurological disorders

Enhancing Agency in Individuals with Depressive Symptoms: The Roles of Effort, Outcome Valence, and Its Underlying Cognitive Mechanisms and Neural Basis

Altered brain network dynamics in motor functional neurological disorders: The role of the right temporo-parietal junction.

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