Connectomic Analysis
Connectomic analysis refers to the study and mapping of the brain's structural and functional networks using neuroimaging and computational tools. In the context of neurosurgery and deep_brain_stimulation (DBS), it enables the identification of specific fiber pathways and network hubs associated with clinical outcomes.
Techniques and Tools
Connectomic analysis integrates data from:
Diffusion-weighted imaging (DWI) and tractography — to reconstruct white matter fiber pathways
Resting-state fMRI — to examine functional connectivity
Normative connectomes — population-averaged brain networks
Patient-specific connectomes — derived from individual imaging data
Common platforms include:
Lead-DBS
MRtrix
FSL
BrainSuite
Applications in DBS
Allows clinicians and researchers to map volumes of activated tissue (VAT) onto brain networks.
Identifies fiber tracts whose modulation correlates with clinical response (e.g., the ocd_response_tract in treatment-resistant_obsessive-compulsive_disorder).
Supports target refinement and the concept of “sweet spots” in subcortical stimulation.
Advantages
Moves beyond anatomical landmarks to network-based neurosurgery.
Enables hypothesis-driven selection of DBS targets.
Can aid in personalized treatment planning by identifying individual network disruptions.
Limitations
Heavily reliant on image quality and accurate coregistration.
Normative connectomes may not capture patient-specific anatomy, especially in diseased brains.
Causal inferences from correlational data remain challenging.
Clinical Example
In the 2025 study by Coenen et al. (Mol Psychiatry), connectomic analysis was used to:
Compare the connectivity profiles of DBS targets (e.g., anteromedial_subthalamic_nucleus, superolateral_medial_forebrain_bundle).
Demonstrate that the ocd_response_tract is embedded within slMFB fibers.
Suggest that symptom improvement in OCD relates to modulation of convergent sub-networks projecting to the dorsomedial_prefrontal_cortex.