Cingulate dynamics track depression recovery with deep brain stimulation.

Deep brain stimulation (DBS) of the subcallosal cingulate (SCC) can provide long-term symptom relief for treatment-resistant depression (TRD)1. However, achieving stable recovery is unpredictable2, typically requiring trial-and-error stimulation adjustments due to individual recovery trajectories and subjective symptom reporting3. We currently lack objective brain-based biomarkers to guide clinical decisions by distinguishing natural transient mood fluctuations from situations requiring intervention. To address this gap, we used a new device enabling electrophysiology recording to deliver SCC DBS to ten TRD participants (ClinicalTrials.gov identifier NCT01984710). At the study endpoint of 24 weeks, 90% of participants demonstrated robust clinical response, and 70% achieved remission. Using SCC local field potentials available from six participants, we deployed an explainable artificial intelligence approach to identify SCC local field potential changes indicating the patient's current clinical state. This biomarker is distinct from transient stimulation effects, sensitive to therapeutic adjustments and accurate at capturing individual recovery states. Variable recovery trajectories are predicted by the degree of preoperative damage to the structural integrity and functional connectivity within the targeted white matter treatment network, and are matched by objective facial expression changes detected using data-driven video analysis. Our results demonstrate the utility of objective biomarkers in the management of personalized SCC DBS and provide new insight into the relationship between multifaceted (functional, anatomical and behavioural) features of TRD pathology, motivating further research into causes of variability in depression treatment.

Long-Term Outcomes of Subcallosal Cingulate Deep Brain Stimulation for Treatment-Resistant Depression.

OBJECTIVE: Deep brain stimulation of the subcallosal cingulate (SCC DBS) has been studied as a potential treatment for severe and refractory major depressive disorder since 2005. The authors used an open-label, long-term follow-up design to examine participants enrolled in a clinical trial of SCC DBS for treatment-resistant depression. METHODS: Long-term outcome data were collected for 28 patients (20 with major depressive disorder and seven with bipolar II disorder; one patient in the major depression subgroup was later reclassified as having bipolar II disorder) receiving SCC DBS for 4-8 years. RESULTS: Response and remission rates were maintained at ≥50% and ≥30%, respectively, through years 2-8 of the follow-up period. Three-quarters of all participants met the treatment-response criterion for more than half of their duration of participation in the study, with 21% of all patients demonstrating continuous response to treatment from the first year onward. Of 28 participants, 14 completed ≥8 years of follow-up, 11 completed ≥4 years, and three dropped out before 8 years. The procedure itself was generally safe and well tolerated, and there were no side effects of acute or chronic stimulation. The rate of medical or surgical complications was consistent with the rate observed in studies of DBS for other indications. There were no suicides. CONCLUSIONS: In >8 years of observation, most participants experienced a robust and sustained antidepressant response to SCC DBS.

Field potential 1/f activity in the subcallosal cingulate region as a candidate signal for monitoring deep brain stimulation for treatment-resistant depression.

Subcallosal cingulate cortex deep brain stimulation (SCC-DBS) is an experimental therapy for treatment-resistant depression (TRD). Refinement and optimization of SCC-DBS will benefit from increased study of SCC electrophysiology in context of ongoing high-frequency SCC-DBS therapy. The study objective was a 7-mo observation of frequency-domain 1/f slope in off-stimulation local field potentials (SCC-LFPs) alongside standardized measurements of depression severity in 4 patients undergoing SCC-DBS. SCC was implanted bilaterally with a combined neurostimulation-LFP recording system. Following a 1-mo off-stimulation postoperative phase with multiple daily recordings, patients received bilateral SCC-DBS therapy (130 Hz, 90 µs) and weekly resting-state SCC-LFP recordings over a 6-mo treatment phase. 1/f slopes for each time point were estimated via linear regression of log-transformed Welch periodograms. General linear mixed-effects models were constructed to estimate pretreatment sources of 1/f slope variance, and 95% bootstrap confidence intervals were constructed to estimate treatment phase 1/f slope association with treatment response (50% decrease in preimplantation symptom severity). Results show the time of recording was a prominent source of pretreatment 1/f slope variance bilaterally, with increased 1/f slope magnitude observed during night hours (2300-0659). Increase in right 1/f slope was observed in the setting of treatment response, with bootstrap analysis supporting this observation in 3 of 4 subjects. We conclude that 1/f slope can be measured longitudinally in a combined SCC-DBS/LFP recording system and likely conforms to known 1/f circadian variability. The preliminary evidence of 1/f slope increase during treatment response suggests a potential utility as a candidate biomarker for ongoing development of adaptive TRD-neuromodulation strategies.NEW & NOTEWORTHY In four patients with treatment-resistant depression undergoing therapeutic deep brain stimulation (DBS), we present the first longitudinal observations of local field potentials (LFP) from the subcallosal cingulate region outside the postoperative period. Specifically, our results demonstrate that frequency-domain 1/f activity is measurable in a combined DBS-LFP recording system and that right hemisphere recordings appear sensitive to mood state, thus suggesting a potential readout suitable for consideration in ongoing efforts to develop adaptive DBS delivery systems.

Do Relational and Self-Definitional Traits Influence Deep Brain Stimulation Device Preference?

Personality psychodynamics have been shown to influence individual responses to psychiatric treatments, including medication. Increasingly, neuromodulation therapies have become available for severe and treatment-resistant depression. This study aims to evaluate patient response to an implanted neurostimulator battery within the framework of relational versus self-definitional personality traits. Relational development is interpersonally oriented and disruptions along this pathway lead to dependency on others for a sense of security and self-worth. Self-definitional development is characterized by autonomy strivings and disruptions lead to self-critical feelings of failing to meet expectations. Patients drawn from a larger study of deep brain stimulation (DBS) for treatment-resistant depression were switched from a non-rechargeable to a rechargeable battery type to maintain stimulation therapy. This switch entailed taking greater personal responsibility for device maintenance and allowed for fewer battery replacement surgeries. Twenty-six patients completed the Depressive Experiences Questionnaire (DEQ) and a questionnaire surveying their preference for DBS battery type. Results show that the DEQ dependency subscale, and more specifically the neediness component of the subscale, is associated with patient preference for the non-rechargeable battery. This suggests that individuals with higher relational needs prefer treatment options that increase contact with and need for medical caregivers and may prioritize this aspect of an intervention over alternative considerations. In contrast, individuals with more self-critical personality traits did not have a battery type preference, indicating that self-definitional needs were not predictive of battery preference. The link between an individual's personality psychodynamics and response to biomedical interventions, including neuromodulation and treatments that incorporate medical devices, deserves further attention.

Epigenetic modification of OXT and human sociability.

Across many mammalian species there exist genetic and biological systems that facilitate the tendency to be social. Oxytocin is a neuropeptide involved in social-approach behaviors in humans and others mammals. Although there exists a large, mounting body of evidence showing that oxytocin signaling genes are associated with human sociability, very little is currently known regarding the way the structural gene for oxytocin (OXT) confers individual differences in human sociability. In this study, we undertook a comprehensive approach to investigate the association between epigenetic modification of OXT via DNA methylation, and overt measures of social processing, including self-report, behavior, and brain function and structure. Genetic data were collected via saliva samples and analyzed to target and quantify DNA methylation across the promoter region of OXT We observed a consistent pattern of results across sociability measures. People that exhibit lower OXT DNA methylation (presumably linked to higher OXT expression) display more secure attachment styles, improved ability to recognize emotional facial expressions, greater superior temporal sulcus activity during two social-cognitive functional MRI tasks, and larger fusiform gyrus gray matter volume than people that exhibit higher OXT DNA methylation. These findings provide empirical evidence that epigenetic modification of OXT is linked to several overt measures of sociability in humans and serve to advance progress in translational social neuroscience research toward a better understanding of the evolutionary and genetic basis of normal and abnormal human sociability.