Causal Role of the Aperiodic Signal for Working Memory

Phase

N/A

Condition

N/A

Treatment

Sham-tRAS

Steep-tRAS

Flat-tRAS

Clinical Study ID

NCT06126809

STUDY00004479

Ages 18-35
All Genders
Accepts Healthy Volunteers

Study 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.

Eligibility Criteria

Inclusion

Inclusion Criteria:

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 thestudy
Ability to speak, read and understand English without a translator
Not color-blind

Exclusion

Exclusion Criteria:

ADHD/ADD (currently under treatment)
Neurological disorder and conditions
Medical or neurological illness or treatment for a medical disorder that couldinterfere 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 atincreased risk or preclude the participant's full compliance with or completion ofthe study
Current use of medications know to produce specific EEG activity known to disruptinterpretations of the findings including but not limited to: benzodiazepines,antipsychotics, antiepileptics and central nervous system stimulants

Study Design

Sham-tRAS

March 25, 2024

December 31, 2025

Study Description

The experiment comprises two experimental sessions. The first session serves as a baseline session where electroencephalography (EEG) is recorded during working memory (WM) task performance. The difficulty of the task is titrated to the individual participant and they are familiarized with the task. In the second session, the participant receives each type of transcranial random aperiodic stimulation (tRAS): steep-tRAS, flat-tRAS, sham-tRAS. Stimulation is delivered in one of these three waveforms for each block while the participant performs the WM task. The type of stimulation that is received is balanced, randomized, and intermixed by block. This study is double-blinded such that the participant and the researcher are not aware of what type of stimulation is being delivered. Each block is approximately 5 minutes and twelve total blocks are collected with stimulation. The type of tRAS for that block (steep-tRAS, flat-tRAS, or sham-tRAS) is started just prior to the beginning of the task block and ramps down at the end of the task block. For each task block, the tRAS takes 15 seconds to ramp up at the beginning and 15 seconds to ramp down at the conclusion of the task block. In total, the participant receives approximately 60 minutes of stimulation, which is approximately 20 minutes of each type of stimulation. Following each task block, participants stare at a fixation cross and relax without stimulation. This "resting-state" EEG recording is used to assess the aftereffects of tRAS on brain activity. The first session will take 2 hours to complete and the second session will take 3 hours to complete.

Connect with a study center

Florida State University
Tallahassee, Florida 32306
United States
Active - Recruiting

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