Neural Interoceptive Processing is Modulated by Deep Brain Stimulation to Subcallosal Cingulate Cortex for Treatment Resistant Depression.

Abstract

Background: Symptoms of depression are associated with impaired interoceptive processing of bodily sensation. The antidepressant effects of subcallosal cingulate deep brain stimulation (SCC DBS) include acute change in bodily sensation, and the SCC target is connected to cortical regions critically involved in interoception. This study tests whether cortical interoceptive processing is modulated by SCC DBS for treatment resistant depression (TRD).

Methods: In eight patients receiving SCC DBS for TRD, we used electroencephalography (EEG) to measure the heartbeat-evoked potential (HEP), a putative read-out of neural interoception, before surgery and over six months of treatment with DBS. We also examined the immediate effect of DBS on the HEP, and correlated HEP change over time with outcomes of treatment for depression.

Results: HEP amplitude increased from baseline after six months of DBS treatment, and this increase was associated with faster antidepressant response. Recording with stimulation on (versus off) had an immediate effect on HEP in the laboratory. Overall, modulation of the HEP was most pronounced in sensors over the left parietal cortex.

Conclusion: Brain-based evidence implies an interoceptive element in the mechanism of treatment efficacy with deep brain stimulation for TRD, and substantiates a theorized connection between interoception and depression.