Causal Role of the Aperiodic Signal for Working Memory

NCT06126809 | Recruiting FDA Device

• 1 other identifier: STUDY00004479
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

Working memory (WM) is the ability to hold relevant information in mind in the absence of sensory input. The capacity for WM is a foundation for cognitive control and higher cognitive function more broadly. Previous research demonstrated that during the delay period of WM tasks, oscillatory electrical activity in the prefrontal cortex in the theta-frequency band (4-8 Hz) increased in amplitude. However, other groups found that the slope of the aperiodic signal in the brain was positively correlated with individual differences in WM capacity. Since low-frequency power and a steeper slope of the aperiodic signal are confounded in many analyses, it is not clear whether the slope of the aperiodic signal or the amplitude of low-frequency oscillations underlie WM capacity. With many studies investigating the causal role of theta oscillations in WM, the purpose of this project is to investigate the role of the aperiodic signal in WM performance.

Conditions

Executive Dysfunction

Keywords

cognitive control; working memory; electroencephalography; transcranial electrical stimulation

Outcome Measures

Primary Outcomes (1)

• Change in number of remembered items

  The number of remembered items, often referred to as working memory capacity, is calculated as the number of items to be remembered multiplied by the number of items successfully remembered divided by the number of total trials. The range of values is 0 to 7 where a larger number denotes a greater number of items that were remembered.

  3 hours

Secondary Outcomes (1)

• Change in slope of the power spectrum of the EEG

  3 hours

Study Arms (3)

Steep-tRAS,

EXPERIMENTAL

Transcranial random aperiodic stimulation (tRAS) delivers 1 milliampere (mA) zero-to-peak amplitude at the target electrodes and 2 mA at the return electrode. The condition of interest, steep-tRAS, mimics a steep slope of the aperiodic signal characterized by greater low relative to high frequency power. Participants receive all three types of stimulation in an intermixed, balanced, and randomized order. There are twelve total blocks of approximately five minutes of stimulation with four blocks of each type of stimulation.

Device: Steep-tRAS

Flat-tRAS

ACTIVE COMPARATOR

Transcranial random aperiodic stimulation (tRAS) delivers 1 milliampere (mA) zero-to-peak amplitude at the target electrodes and 2 mA at the return electrode. The active control, flat-tRAS, mimics a flat slope aperiodic signal characterized by greater high relative to low frequency power. Participants receive all three types of stimulation in an intermixed, balanced, and randomized order. There are twelve total blocks of approximately five minutes of stimulation with four blocks of each type of stimulation.

Device: Flat-tRAS

Sham-tRAS

SHAM COMPARATOR

Transcranial random aperiodic stimulation (tRAS) delivers 1 milliampere (mA) zero-to-peak amplitude at the target electrodes and 2 mA at the return electrode. For active sham stimulation, steep-tRAS or flat-tRAS is delivered for only 15 seconds at the beginning and end of the block. This mimics the skin sensations (e.g., itching, burning, tingling) to assist with blinding the participant. Participants receive all three types of stimulation in an intermixed, balanced, and randomized order. There are twelve total blocks of approximately five minutes of stimulation with four blocks of each type of stimulation.

Device: Sham-tRAS

Interventions

Steep-tRAS DEVICE

Stimulation will be delivered via the NeuroConn Direct Current Stimulator Plus Multiple Channels, an investigational electrical non-invasive brain stimulation device that is being used for foundational neuroscience and translational research.

Steep-tRAS,

Flat-tRAS DEVICE

Stimulation will be delivered via the NeuroConn Direct Current Stimulator Plus Multiple Channels, an investigational electrical non-invasive brain stimulation device that is being used for foundational neuroscience and translational research.

Flat-tRAS

Sham-tRAS DEVICE

Stimulation will be delivered via the NeuroConn Direct Current Stimulator Plus Multiple Channels, an investigational electrical non-invasive brain stimulation device that is being used for foundational neuroscience and translational research.

Sham-tRAS

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Between the ages of 18 and 35
• Able to provide informed consent
• Normal or corrected-to-normal vision
• Willing to comply with all study procedures and be available for the duration of the study
• Ability to speak, read and understand English without a translator
• Not color-blind

You may not qualify if:

• ADHD/ADD (currently under treatment)
• Neurological disorder and conditions
• Medical or neurological illness or treatment for a medical disorder that could interfere with study participation, e.g., unstable cardiac disease, HIV/AIDS, malignancy, liver or renal impairment
• Prior brain surgery
• Any brain devices/implants, including cochlear implants and aneurysm clips
• History of traumatic brain injury
• (For females) Pregnant
• Anything that, in the opinion of the investigator, would place the participant at increased risk or preclude the participant's full compliance with or completion of the study
• Current use of medications know to produce specific EEG activity known to disrupt interpretations of the findings including but not limited to: benzodiazepines, antipsychotics, antiepileptics and central nervous system stimulants

Sponsors & Collaborators

• Florida State University: lead

Study Sites (1)

Florida State University

Tallahassee, Florida, 32306, United States

RECRUITING

Study Officials

• Justin Riddle, PhD

  Florida State University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Justin Riddle, PhD

CONTACT

850-645-2389; jriddle@fsu.edu

Lauren Jackson, BS

CONTACT

850-644-9869; lauren.jackson@fsu.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: This study is double-blinded at the level of "runs" within a single session. Participants and the researchers at the time of stimulation are unaware of which type of stimulation the participant will receive for each block. This is accomplished using randomization codes maintained within the computer. Furthermore, this study utilizes an active sham stimulation. This means that the active sham condition includes some stimulation, mimicking the skin sensations associated with tRAS. Participants receive all three types of stimulation in a single session over twelve five-minute blocks with an intermixed, balanced, and randomized order.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: All participants receive all three types of transcranial random aperiodic stimulation (tRAS): steep-tRAS, flat-tRAS, and sham-tRAS. The type of stimulation received is randomized and intermixed for each task block lasting approximately 5 minutes. The participant receives 12 task blocks, each with one of the stimulation types that are randomized, intermixed, and balanced for order.

Study Record Dates

• First Submitted: November 7, 2023
• First Posted: November 13, 2023
• Study Start: March 25, 2024
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: January 12, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Time Frame: 9 to 36 months following publication
• Access Criteria: Deidentified individual data that supports the results will be shared provided the investigator who proposes to use the data has approval from an IRB, IEC, or REB and an executed data use/sharing agreement with FSU.

Locations

US (1)