Objective: The aim of this study was to identify the features of subthalamic tracts in PD patients with ICD.
Background: Recurrent negative feedback loops from subthalamic nucleus (STN) via the cerebral cortex to the selfsame STN are mentioned between the main mechanisms of dynamically controlling actions [1]. Different studies of impulse control disorders (ICD) in Parkinson’s disease (PD) are carried out to identify the features of STN-associated tracts in PD patients [2].
Method: We analyzed 25 PD patients, include 7 cases of ICD (all used agonists). Patients’ characteristics are presented in the table (Figure 1). To assess the motor symptoms UPDRS is used, drug therapy – LEDD, QUIP is used to revealed ICD.
Calculation of recurrent tracts both starting and ending in same STN is not trivial because of limited MRI resolution. The indirect way to study feedback loops is statistical processing of named two tracts type spatial distribution (Figure 2). Statistics of tracts ending/starting in STN are evaluated by frequentist probability definition from tract density spatial distribution. This approach allows to calculate spatial distribution of ratio of joint probabilities of tracts ending/starting in STN (Figure 3, 2 ICD– and 2 ICD+ patients).
Results: Tracts ending in STN are more probable in axial slices near this structure in the case of ICD+. Unlike this, ratio of joint probabilities in the case of ICD– are characterized by opposite behavior: tracts ending in STN are more probable in axial slices closer to parieto-temporal surface of cerebral hemispheres. Probably, this is a potential sign of recurrent negative feedback STN degradation in patient with ICD.
Conclusion: Preliminary index based on spatial distribution of ratio of joint probabilities of tracts ending/starting in STNs is proposed. Tracts ending in STN are more probable in axial slices located in the different positions. That is probably potential sign to diagnose ICD for PD patients. Further studies of the STN nucleus tracts and cortico-subthalamic networks to investigate its role for the ICD are needed.
Description of patient groups
Algoritm of type tracts distribution processing
Calculation of path ratio probability distribution
References: 1. Damian M. Herz et al. Subthalamic control of impulsive actions: insights from deep brain stimulation in Parkinson’s disease. Brain. 2024; 147; 3651–3664. doi.org/10.1093/brain/awae184.
2. Federico Carbone, Atbin Djamshidian Impulse control disorders in Parkinson’s disease: an overview of risk factors, pathogenesis and pharmacological management. CNS Drugs. 2024; 38:443–457. doi.org/10.1007/s40263-024-01087-y.
To cite this abstract in AMA style:
A. Buniak, V. Bayarchyk, A. Mikitchuk. Approaches to understanding the role of STN in the development of ICD in Parkinson’s disease [abstract]. Mov Disord. 2025; 40 (suppl 1). https://www.mdsabstracts.org/abstract/approaches-to-understanding-the-role-of-stn-in-the-development-of-icd-in-parkinsons-disease/. Accessed October 5, 2025.« Back to 2025 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/approaches-to-understanding-the-role-of-stn-in-the-development-of-icd-in-parkinsons-disease/