Neural Noise- Combined intracranial DBS and EEG recordings in Tourette syndrome reveal thalamo-frontal functional connectivity patterns.1
- iEEG serves as a readout for neuromodulation and supports closed-loop DBS target refinement.1 1
Weekly enrichment (2026-07-20)
- The source study (Molecular Psychiatry 2025, DOI 10.1038/s41380-025-03220-9) recorded bilateral thalamic local field potentials with the Medtronic Percept PC neurostimulator (BrainSense streaming) simultaneously with high-density scalp EEG in eight male Tourette-syndrome patients aged 27–38, with stimulation switched off.2
- DBS leads targeted the centromedian nucleus–nucleus ventrooralis internus (CM-Voi) or ventral anterior/ventral lateral nuclei (VA/VL); patients were treated at University Hospital Cologne between 2009 and 2022, and symptom severity was indexed with the Yale Global Tic Severity Scale (YGTSS) total tic score.2
- High-density EEG was acquired at a 5000 Hz sampling rate; functional connectivity was quantified as phase synchronization using the phase slope index (PSI), compared against surrogate data, with no significant hemisphere effects (justifying treating left and right thalamus as independent samples).2
- The key finding is a spatially and spectrally distinct thalamo-frontal oscillatory network in the alpha band (8–12 Hz), specific to that band rather than theta or beta, whose connectivity strength was negatively correlated with tic severity (stronger alpha coupling, milder symptoms).2
- Reduced thalamo-frontal alpha connectivity localized to sensorimotor and inferior parietal regions preceded tic onset, implicating this network directly in tic generation; symptom and pre-tic associations were present in connectivity but not in the pure power spectra.2
- The authors frame these connectivity features as candidate control signals for closed-loop (adaptive) DBS in Tourette syndrome, extending prior intraoperative LFP work to a chronically implanted sensing device.2
- Context: an embedded closed-loop bilateral centromedian-parafascicular thalamic DBS trial in 4 medication-refractory TS patients found the approach feasible and safe, with conventional DBS yielding mean 33.3% YGTSS and 52.8% Modified Rush Videotape improvement and closed-loop showing no statistical difference from continuous stimulation.3
- Context: earlier CM-parafascicular recordings showed increased low-frequency thalamic activity and decreased motor-cortex beta during tics, with a pre-tic M1 beta increase helping separate tics from voluntary movement—an alternative biomarker family (power-based) to the connectivity markers in the primary study, both feeding closed-loop DBS decoders (often LDA classifiers).4