Invasive Decoding and Stimulation of Altered Reward Computations in Depression
Icahn School of Medicine at Mount Sinai
Summary
Novel invasive neurostimulation stimulation strategies through neurosurgical interventions are emerging as a promising therapeutical strategy for major depressive disorder. These have been applied mostly to the anterior cingulate cortex, but other limbic brain regions have shown promise as anatomical targets for new neurostimulation strategies. The researchers seek to study neural activity in limbic brain areas implicated in decision behavior and mood regulation to identify novel targets for treatment through electrical stimulation. To do this, the study team will record local field potentials (LFPs) from the orbitofrontal cortex, hippocampus and amygdala of epilepsy participants undergoing invasive monitoring (intracranial encephalography, iEEG) during choice behavior. Leveraging the high co-morbidity of depression and intractable epilepsy (33-50%), neural responses will be compared to reward across depression status to identify abnormal responses in depression. Finally, the researchers will use these as biomarkers to guide development of neurostimulation strategies for the treatment of depression.
Description
Participants (n=24) will complete a decision-making task in which participants will make decisions under uncertainty and seek to maximize rewards. The researchers will assess behavioral (risk attitudes) and neural (LFP) responses using a combination of intracranial recordings and computational modeling. A subset of patients will complete the game a second time under electrical stimulation of pre-identified anatomical targets in orbitofrontal cortex, hippocampus or amygdala. In addition, patients' depression status will be assessed through questionnaires (BDI-II and HDSA). Finally, the research…
Eligibility
- Age range
- 18–80 years
- Sex
- All
- Healthy volunteers
- No
Inclusion Criteria: \- The study will follow clinical criteria for epilepsy patient recruitment for invasive monitoring. As a results, individuals of adults of all ages are expected to be included in this study. Exclusion Criteria: * Adults over 80 years of age will be excluded as per concerns of cognitive decline. * Children under 18 will be excluded from the study since the maturation of frontal lobes continues through adolescence and significant differences in frontal lobe functioning between children younger than 18 and adults are often observed.
Interventions
- ProcedureBrain stimulation
Brain stimulation will be performed after collection of clinical seizure data. Bipolar stimulation to one or several adjacent electrodes will be applied. Stimulation design will be either determined prior to testing or designed according to results from neurobehavioral assessments. Stimulation will consist of biphasic, constant-current trains of stimulation pulses at 100 Hz, with 100 ms pulse width or a sinusoidal wave of a predefined mean band frequency (i.e. 6Hz for θ, 11Hz for α, 20Hz for β, etc.). Stimulation intensity will be ≤6 mA, consistent with parameters used for clinical mapping, for the duration of the behavioral task or for short (2-3 s) periods of time at given epochs during the task (i.e. outcome evaluation). Clinical personnel will be available during stimulation to help monitor stimulation-induced after-discharges; if any are detected, stimulation intensity will be dialed down or terminated.
Location
- Icahn School of Medicine at Mount SinaiNew York, New York