DBS Sensing Reveals Ketamine-Linked SCC Activity in Depression

Direct Human Evidence: Ketamine and Affective States Overlap in SCC Activity

The 2026 study published via OpenAlex (W7212351311) provides the first direct evidence in humans that both ketamine administration and emotional states modulate the same frequency bands in the subcallosal cingulate cortex (SCC), a key region implicated in depression. Researchers analyzed 5,907 hours of SCC sensing data from patients with treatment-resistant depression (TRD) undergoing deep brain stimulation (DBS), including 47 ketamine dosing episodes and 485 participant-triggered recordings over 193 days. The study found that both ketamine exposure and negative affective events (such as anxiety and sadness) produced a convergent bilateral shift toward increased fast-band (21–40 Hz) SCC activity, particularly at 23.44 Hz, though with distinct temporal and spectral characteristics.

Mechanistic Insights: Temporal and Spectral Patterns in SCC Dynamics

Ketamine and affective states engage overlapping SCC frequency bands but differ in how these signals evolve over time and across hemispheres. Post-ketamine administration, SCC recordings showed lower aperiodic-adjusted 5–20 Hz power and higher 21–40 Hz power, with a pronounced bilateral increase in 23.44 Hz activity. Notably, affective events such as anxiety and sadness also drove increases in this frequency, but these changes began before self-reported mood shifts and peaked about 15 minutes later. In contrast, neutral or positive events led to smaller decreases or lateralized changes. This nuanced temporal relationship suggests that SCC fast-band activity is a context-dependent signal, reflecting both pharmacologic and emotional brain states, but with different spectral and timing signatures.

Policy and Research Implications: Toward Adaptive, Personalized DBS

The findings challenge the prevailing DBS approach of using static band-power thresholds to guide stimulation in depression. Instead, the study supports the development of adaptive DBS protocols that dynamically respond to evolving SCC signals, distinguishing between pharmacologic effects (e.g., ketamine) and affective states. This insight is particularly relevant for ongoing and future clinical trials of neuromodulation in TRD, such as those registered with NCT01984710 (SCC DBS in depression). Adaptive systems could leverage real-time sensing to personalize stimulation parameters, potentially improving efficacy and reducing side effects. Importantly, the study demonstrates the feasibility of chronic SCC sensing in real-world settings, providing a foundation for closed-loop device development and regulatory evaluation by agencies such as the U.S. Food and Drug Administration (FDA).

Risks, Limitations, and Unknowns

While the study offers unprecedented granularity in SCC activity mapping, several limitations remain. The sample size is small, and the cohort is highly selected for severe, treatment-resistant depression, which may limit generalizability. The overlap in frequency bands between ketamine and affective states raises the risk of misinterpreting brain signals in adaptive DBS systems, potentially leading to inappropriate stimulation if context is not adequately decoded. Furthermore, the long-term effects of combining pharmacologic (ketamine) and device-based (DBS) interventions are not yet understood, and the safety profile of chronic SCC sensing and adaptive stimulation requires further investigation in larger, multi-site trials.

Future Directions: Integrating Pharmacologic and Device-Based Therapies

This study advances the field by demonstrating that SCC fast-band activity is a dynamic, context-sensitive biomarker, opening the door for adaptive neuromodulation strategies in depression. Future research should focus on refining algorithms that can distinguish between pharmacologic and affective brain states in real time, validating findings in larger and more diverse populations, and establishing regulatory pathways for adaptive DBS devices. The integration of chronic brain sensing with pharmacologic interventions like ketamine represents a promising but complex frontier in personalized psychiatry, with the potential to transform care for patients with refractory mood disorders.

How we research: This article was written and reviewed by Dr. Alex M. Greene, MD, PhD (psychiatry and neuroscience), on 2026-09-12. Primary source: OpenAlex W7212351311.