Invasive Decoding and Stimulation of Altered Reward Computations in Depression Patients

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.