Analysis of Electrocorticographic Signals

NCT03785028 | Completed Results

• 5 other identifiers: 2015-0282Protocol Version 6/18/2019A538900SMPH\PSYCHIATRY\PSYCHIATRY2R01MH095984
• Study Type: interventional
• Target: 5
• Locations: 1 country
• Sites: 1

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.

Conditions

Epilepsy

Outcome Measures

Primary Outcomes (3)

• Qualitative Measure: Prioritization Cue-related Changes in the Neural Representation of Stimuli Reported as Binary for Prioritized and Unprioritized Item Decodability

  This experiment will use a machine learning analysis -- multivariate pattern classification -- to "decode" the brain signals measured by the electrocorticography electrodes. That is, the analysis will determine if the face/word/scene that is being remembered is being represented by these particular brain signals). The primary outcome will be to assess what happens to the neural representation of, say, a face, when the patient is probed that the other stimulus presented on that trial will be tested first - i.e., the analysis will assess the decodability of the two items as a function of their priority for upcoming task demands. Reported here is the categorical performance of Support Vector Machines (SVMs) trained using a 10-fold cross-validation procedure to decode the prioritized and unprioritized memory items (faces, scenes, or words).

  Twenty minutes

• Qualitative Measure: Working Memory Delay Period Phase-amplitude Coupling Reported as Direction (Increase/Decrease) for Region and Stimulus Type

  Phase-amplitude coupling (PAC) refers to the synchrony between low frequency oscillations and bursts of high-frequency signal, which is interpreted as a proxy for neuronal firing. The primary outcome measure is whether the level of phase-amplitude coupling associated with a stimulus will change (increase, decrease, change to different frequencies) after that stimulus is prioritized or deprioritized by the cue. Reported here is the direction of PAC between low theta oscillations (6 Hz) and high-gamma bursts (\>140 Hz) in binary terms according to whether the PAC increased or decreased for the three stimulus types (faces, scenes, or words) in electrode signals analyzed in different brain regions.

  Twenty minutes

• Experiment 3.b. Covert Spatial Attention-related Changes in Phase-amplitude Coupling

  Phase-amplitude coupling refers to the synchrony between low frequency oscillations and bursts of high-frequency signal, which is interpreted as a proxy for neuronal firing. The primary outcome measure is whether the level of phase-amplitude coupling in tissue representing a region of space that is irrelevant for an entire block of trials will change in a manner that mirrors the dynamic changes expected for each trial's uncued location, or whether it will be insensitive to shifts of attention that are, by definition, never relevant for that tissue over the course of that block of trials.

  Twenty minutes

Study Arms (1)

Experimental Arm

EXPERIMENTAL

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

Behavioral: working memory and attention

Interventions

working memory and attention BEHAVIORAL

working memory and attention tasks

Experimental Arm

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• University of Wisconsin, Madison: lead
• National Institute of Mental Health (NIMH): collaborator

Study Sites (1)

University of Wisconsin

Madison, Wisconsin, 53705, United States

Location

MeSH Terms

Conditions

Epilepsy

Condition Hierarchy (Ancestors)

Brain Diseases; Central Nervous System Diseases; Nervous System Diseases

Limitations and Caveats

Study underpowered for meaningful results. Working memory tasks prove challenging for this patient population, leading to unreliable or uninterpretable data. Recruitment challenges related to coverage of data recording, and cognitive ability requirements, are prevalent in this patient population leading to small number of data sets collected and analyzed.

Results Point of Contact

• Title: Brad Postle, PhD
• Organization: University of Wisconsin - Madison

postle@wisc.edu

608-262-4330

Study Officials

• Bradley R Postle, PhD

  University of Wisconsin, Madison

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: basic science

Study Record Dates

• First Submitted: December 14, 2018
• First Posted: December 24, 2018
• Study Start: July 19, 2019
• Primary Completion: February 21, 2021
• Study Completion: February 21, 2021
• Last Updated: May 1, 2024
• Results First Posted: May 1, 2024

Record last verified: 2024-04

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)