Intraoperative Subcallosal Cingulate Local Field Potential Spectral Analysis During Emotion-Evoking Music in Treatment-Resistant Depression With Multitarget Deep Brain Stimulation: A Case Report

The subcallosal cingulate (SCC/sgACC) is a proposed target for deep brain stimulation (DBS) in treatmentresistant depression (TRD), and intraoperative local field potentials (LFPs) are being explored as a source of candidate biomarkers.We report a 52-year-old woman with early-onset, highly refractory TRD and comorbid obsessive-compulsive and anxiety disorders who underwent tractography-guided multitarget DBS with four 8-contact nondirectional leads: two in the SCC and two along a trajectory through the posterior-ventral nucleus accumbens (NAc), the anterior bed nucleus of the stria terminalis (BNST), and the anterior limb of the internal capsule (ALIC).In this exploratory technical observation, LFPs were recorded from the macrocontact of a microelectrode in the left SCC of the awake patient, with stimulation OFF, during two music trials: one with a no-music baseline, two neutral songs (rock and classical), and her favorite (happy) song, and one with a baseline and a sad song.Spectra (Welch's method) and aperiodic exponents were compared post hoc, and broadband (3-45 Hz) power during each song was expressed relative to the baseline of the same trial.Verification of the raw data identified non-neural features that could mimic affective effects: the exported segments had been downsampled without anti-alias filtering, so 60-Hz mains interference appeared as narrow lines at 40 and 20 Hz, and 23 corrupted samples in the first 4 s of the happy-song segment inflated its power more than 200-fold.After their exclusion, broadband power relative to baseline was higher during the sad song (1.43-fold) than during the happy song (0.69-fold; between-song ratio 2.06, permutation p=0.024) and the rock song (0.57-fold; ratio 2.48, p=0.004), but not the classical piece (1.13-fold; p=0.45).Absolute power did not differ between the sad and happy songs, power rose transiently before the sad song began and remained elevated after it ended, and aperiodic exponents showed no valence-related pattern.Three months after stimulation onset, the 17-item Hamilton Depression Rating Scale score decreased from 26 to 13 and the Hamilton Anxiety Rating Scale score from 19 to 8.This single-case observation provides, at most, a weak post hoc signal of valence-related SCC broadband activity and mainly shows how acquisition and export artifacts can mimic affective LFP effects.Raw-data verification, anti-alias filtering, and repeated, counterbalanced conditions are prerequisites for evaluating intraoperative SCC LFPs as candidate biomarkers.