Working Memory
Conditions
Brief summary
This study will assess the impact of traveling wave transcranial alternating current stimulation (tACS) on working memory performance in adults.
Detailed description
Transcranial alternating current stimulation (tACS) can non-invasively alter neuroelectric activity in the brain by applying weak time-varying electric currents via the scalp. Complex patterns of electric brain activity can take the form of traveling waves - spatially coherent brain rhythms that gradually propagate through the neocortex. Traveling waves are crucial for the temporal coordination of informational flow in the brain. Using the novel traveling-wave transcranial alternating current stimulation (tACS) approach, the investigators will explore the effects of frontal-to-parietal and parietal-to-frontal traveling waves on working memory performance and brain electrophysiology in adults.
Interventions
DEVICETranscranial alternating current stimulation (tACS)
Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
Sponsors
University of Minnesota
Brain & Behavior Research Foundation
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Caregiver, Investigator)
Intervention model description
Randomized, within-subject crossover assignment
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
1. Age between 18 and 45 years old. 2. Confident level of English language.
Exclusion criteria
1. History or evidence of chronic neurological or mental disorder. 2. Metal or electric implant in the head, neck, or chest area. 3. History of head injuries with loss of consciousness. 4. Any acute or chronic medical condition that requires ongoing pharmacological treatment. 5. Pregnancy or breast-feeding. 6. Alcohol or drug addiction.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Working Memory Accuracy (N-back Task) | During each stimulation block (approximately 20 minutes per block) in two study sessions conducted on separate days and separated by a minimum 48-hour washout period. | Accuracy (proportion of correct responses) during performance of the N-back working memory task within each stimulation block. Values represent absolute task performance during active or sham stimulation in a within-subject crossover design. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes in Reaction Time | During each stimulation block (approximately 20 minutes per block) in two study sessions conducted on separate days and separated by a minimum 48-hour washout period. | Reaction time (milliseconds) during performance of the N-back working memory task within each stimulation block. Values represent absolute reaction time during active or sham stimulation conditions in a within-subject crossover design |
| Theta-band Frontoparietal EEG Phase Connectivity (dwPLI) | Resting-state EEG was recorded immediately before and immediately after each stimulation block in two sessions conducted on separate days (≥48-hour washout). | Frontoparietal phase synchronization in the theta band (4-7 Hz), quantified using the debiased weighted Phase-Lag Index (dwPLI) between frontal and parietal electrode pairs. Connectivity values range from 0 to 1, with higher values indicating stronger phase synchronization |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORIvan Alekseichuk, PhD
University of Minnesota
Participant flow
Recruitment details
A total of 34 participants were enrolled in the study. Of these, 29 participants completed all study procedures and received all stimulation conditions.
Pre-assignment details
All participants were assigned to a single randomized within-subject crossover arm. Each participant completed two study sessions separated by a washout period, receiving two active stimulation conditions per session. Across both sessions, every participant received all four active stimulation conditions exactly once. Counts shown for individual conditions are session-specific and do not represent separate treatment arms.
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 29 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants |
| Race (NIH/OMB) More than one race | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 29 Participants |
| Race (NIH/OMB) White | 0 Participants |
| Sex: Female, Male Female | 14 Participants |
| Sex: Female, Male Male | 15 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 29 | 0 / 29 | 0 / 29 | 0 / 29 |
| other Total, other adverse events | 0 / 29 | 0 / 29 | 0 / 29 | 0 / 29 |
| serious Total, serious adverse events | 0 / 29 | 0 / 29 | 0 / 29 | 0 / 29 |
Outcome results
None listed