About this trial
This project will use intracranial recordings and stimulation of the human brain to understand the unique contributions of the posterior cingulate cortex (PCC) to episodic memory behavior. The goal is to test how distinct subregions of the PCC differentially contribute to memory-based decisions (e.g., have I seen this picture before?). The ability to perform invasive studies of the human brain is through routine clinical monitoring of brain activity which occurs during the neurosurgical treatment of epilepsy. However, this project only focuses on the basic science of PCC and memory behavior. Specifically, the investigators will use single-0cell and population measures of brain activity to test a new theory of PCC function which focuses on the executive processes needed to support memory retrieval and memory-based decisions. By studying the PCC, a convergence zone of memory and executive brain systems, progress can be made in elucidating how the failure to successfully leverage past experiences in daily behavior can occur as a common symptom of both neurodegenerative disease (e.g., Alzheimer's disease) and multiple psychiatric conditions (e.g., schizophrenia) implicating PCC dysfunction.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
All participants are patients undergoing invasive brain monitoring for epilepsy and will be asked to consent to participation in this basic science protocol (which is focused on the patient group but is not focused on the study of epilepsy).
Disqualifiers
Individuals not undergoing invasive brain monitoring for epilepsy.
Individuals outside of the age range (18-50 yrs).
Individuals with cognitive impairment or intellectual difficulty.
Trial design
Crossover
Treatments tested in this trial
Cognitive testing
BehavioralCognitive tasks testing executive and episodic based decisions, and the switching between these processes.
Treatment groups
Trial outcomes
Primary outcomes
Episodic/Executive behavioral task performance accuracy
Participants will perform three tasks each testing the accuracy of executive (reward) or episodic (memory strength) based decisions. Outcome measures will be decision accuracy (% correct).
Episodic/Executive behavioral task performance speed
Participants will perform three tasks each testing the speed of executive (reward) or episodic (memory strength) based decisions. Outcome measures will be response/decision reaction time (milliseconds).
Changes in high-frequency electrophysiological brain response
During behavioral task performance, electrophysiological signals recorded from the brain will be quantified for changes in the mean high-frequency activity (70-150 Hz) amplitude during correct and incorrect episodic/executive decisions. The goal is to track this electrophysiological activity to quantify if and when brain activity in the posterior cingulate cortex occurs during memory and non-memory based decisions.
Sponsors and contacts
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