Neural Correlates of Psychiatric Disorders

Primary outcomes

1. Neural activity correlating with the Center for Epidemiologic Studies Depression Scale - Revised (CESD-R)

   Time frame: During patient's epilepsy monitoring stay, approximately 15 minutes

   The Center for Epidemiologic Studies Depression Scale - Revised (CESD-R) is a commonly used and well validated depression screening tool consisting of 20 questions. Scores range from 0 to 60 and a score of 16 or above indicates a risk for clinical depression. CESD-R scores will be correlated with resting state measures of neural activity and connectivity

2. Neural activity correlating with the State-Trait Anxiety Inventory (STAI)

   Time frame: During patient's epilepsy monitoring stay, approximately 15 minutes

   The State-Trait Anxiety Inventory (STAI) is a validated anxiety scale that screens for current anxiety state and chronic anxiety trait. It consists of 40 questions with scores ranging from 20 to 80. A score of 40 or above indicates risk of anxiety. STAI scores will be correlated with resting state measures of neural activity and connectivity

3. Neural activity correlating with the Yale-Brown Obsessive Compulsive Scale (YBOCS)

   Time frame: During patient's epilepsy monitoring stay, approximately 15 minutes

   The Yale-Brown Obsessive Compulsive Scale (YBOCS) is the most commonly used and well validated measure of obsessive compulsive features. It consists of 10 questions with scores ranging from 0 to 40. A score of 8-15 indicates mild OCD, 16-23 indicates moderate OCD, 24-31 indicates severe OCD and 32-40 indicates extreme OCD. YBOCS scores will be correlated with resting state measures of neural activity and connectivity

4. Neural activity correlating with the Barratt Impulsiveness Scale (BIS11)

   Time frame: During patient's epilepsy monitoring stay, approximately 15 minutes

   The Barratt Impulsiveness Scale (BIS11) is a well validated measure of impulsive traits that consists of 30 questions. The scores of the BIS11 range from 30 to 120 with scores above 72 indicating high levels of impulsivity. BIS11 scores will be correlated with resting state measures of neural activity and connectivity

5. Local field potential changes in response to study tasks

   Time frame: During patient's epilepsy monitoring stay, approximately 20-30 minutes

   These local field potential changes are neural recordings in response to the stop signal tasks and n back tasks. In the stop signal reaction time task the subject will see a visual stimulus and be asked to press a button to respond. On some trials an auditory stimulus will also be presented which will indicate that the subject should not press the response button (they should suppress their response). In the n-back verbal working memory task the subject will see a series of words presented sequentially on a screen. During each word presentation the subject will press a button to indicate whether or not the word matches that presented n trials prior

6. Behavioral performance changes with stimulation

   Time frame: During patient's epilepsy monitoring stay, approximately 20-30 minutes

   Stimulation will occur during the stop signal task and n back task. In the stop signal reaction time task the subject will see a visual stimulus and be asked to press a button to respond. On some trials an auditory stimulus will also be presented which will indicate that the subject should not press the response button (they should suppress their response). In the n-back verbal working memory task the subject will see a series of words presented sequentially on a screen. During each word presentation the subject will press a button to indicate whether or not the word matches that presented n trials prior. Stimulation will be delivered through pre-selected SEEG electrodes via the Ripple Neuromed Summit system. Test stimulation will be performed prior to stimulation during the task to test for safety and tolerability, with the patient monitored for symptoms by a neurosurgeon or neurologist.

7. Single unit neuronal spiking changes in response to study tasks

   Time frame: During patient's epilepsy monitoring stay, approximately 20-30 minutes

   Single neuron (single unit) spiking activity is recorded through SEEG micro neural recordings in response to patients completing neuro cognitive tasks.