Obsessive-Compulsive Disorder Response Tract (ORT)
The Obsessive-Compulsive Disorder Response Tract (ORT) refers to a specific subset of white matter fibers identified through connectomic_analysis as being strongly associated with clinical improvement in patients undergoing deep_brain_stimulation (DBS) for treatment-resistant OCD.
Origin and Concept
The ORT was defined retrospectively from aggregated stimulation data in multiple DBS cohorts, correlating fiber engagement with positive treatment outcomes. It represents a reproducible bundle of fibers modulated in successful responders, particularly across different DBS targets.
The tract connects subcortical regions to cortical areas such as the dorsomedial_prefrontal_cortex (dmPFC).
It traverses key limbic structures involved in affective regulation and cognitive control.
It overlaps anatomically with parts of the superolateral_medial_forebrain_bundle (slMFB), particularly its medial and ventral components.
Clinical Significance
The ORT serves as a predictive biomarker for therapeutic response to DBS in OCD.
It offers a network-based framework for targeting, moving beyond traditional nucleus-based stimulation.
Precise engagement of the ORT during DBS programming may enhance efficacy and reduce side effects.
Research Context
In the 2025 study by Coenen et al. (Mol Psychiatry), the ORT is:
Shown to be entirely embedded within the slMFB.
Identified as a “fiber selection” within a broader and more distributed connectomic target.
De-emphasized as a singular pathway, supporting the idea that different OCD sub-networks converge via slMFB and structures like the anteromedial_subthalamic_nucleus.
Limitations
Definition is based on retrospective data; prospective validation and standardization across centers are needed.
May vary in structure and cortical projections depending on individual anatomy.