Analysis of Electrocorticographic Signals

NCT ID: NCT03785028

Last Updated: 2024-05-01

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 5 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-07-19
• Study Completion Date: 2021-02-21

Brief Summary

The objectives of this research are to understand how the brain can keep information in mind ("working memory"), and use this information to guide behavior. The two experiments that fall under this study will collect brain signals from epilepsy patients who are having surgery as part of their treatment. More specifically, these signals will be studied from the time while the patient is performing two cognitive tasks.The endpoints are publication of the results from each of the proposed experiments in peer-reviewed journals.

Detailed Description

There are 2 separate experiments proposed, both of which use repeated-measures designs.

1: Electrocorticography (ECoG) study of visual working memory. Each trial from the behavioral task will start by presenting subjects with two visual images, one each from two of these three categories: faces, words, and outdoor scenes. They will then be cued as to which one they'll be tested on with a recognition probe, and after the first probe the cuing-probing process is repeated. Patients selected for this study will have depth electrodes implanted in the left medial temporal lobe and/or grids covering left occipital, temporal, and/or parietal cortex, and suitability of a patient's data for the final dataset will require that a minimum of one stimulus category can be decoded from them. (The precise minimum number of trials required cannot be calculated a priori, because this requires knowing the signal-to-noise ratio in a dataset, a property that is highly variable in electrocorticography data.)

2. Electrocorticography of spatial selective attention. Each trial from the behavioral task will start by presenting subjects with a white "+" on a screen, with each arm pointing to a potential target location. During each 92-trial block of trials, only two 180-degree opposing locations will ever be cued, with one arm of the "+" turning yellow and the opposing one turning blue, to indicate with 75% validity the location at which an oriented Gabor patch will appear (5 degrees from fixation; cue color mapping counterbalanced), requiring a speeded "R/L" tilt judgment. Orthogonal to cue-color configuration, half of the trials in each block will begin with presentation of an "x" that will rotate by 45 degrees with an unpredictable lag (.5 sec +/- .3). On these trials, the cue-to-target interval (i.e., from rotation to "+" to color-cue onset) will be 750 msec. On trials that begin with the onset of a "+", cue-to-target interval will vary unpredictably between 650, 750, and 850 msec. Decomposition of alpha-band oscillations (brain waves cycling at roughly 10 times per second) into components associated with each location will be derived by filtering the whole-scalp signal with weights from the inverted encoding model trained to encode the four critical locations.

Conditions

Epilepsy

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Experimental Arm

Only arm of this basic science study, participants will undergo working memory and attention tasks

Group Type: EXPERIMENTAL

working memory and attention

Intervention Type: BEHAVIORAL

working memory and attention tasks

Interventions

working memory and attention

working memory and attention tasks

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• Participants with implanted electrode arrays who are willing to participate and able to cooperate and follow research instructions will be recruited.
• Must be able to read
• Must be able to name objects
• Must be able to articulate thoughts with spoken language

Exclusion Criteria

• post-operative pain requiring narcotics
• repeated seizures clouding consciousness
• IQ of 85 and below
• post-operative subdural bleeding
• cerebral pathology affecting the cortical regions from which recordings are made
• women who are pregnant, or who think they may be pregnant

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

National Institute of Mental Health (NIMH)

NIH

Sponsor Role: collaborator

University of Wisconsin, Madison

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Bradley R Postle, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Wisconsin, Madison

Locations

University of Wisconsin

Madison, Wisconsin, United States

Countries

United States

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Other Identifiers

Protocol Version 6/18/2019

Identifier Type: OTHER

Identifier Source: secondary_id

A538900

Identifier Type: OTHER

Identifier Source: secondary_id

SMPH\PSYCHIATRY\PSYCHIATRY

Identifier Type: OTHER

Identifier Source: secondary_id

2R01MH095984

Identifier Type: NIH

Identifier Source: secondary_id

View Link

2015-0282

Identifier Type: -

Identifier Source: org_study_id