Healthy
Conditions
Brief summary
Many studies have examined the effects of transcranial alternating current stimulation (tACS) on working memory, showing that low-intensity stimulation can enhance cognitive performance by modulating neuronal activity, particularly in the frontal cortex and the parietal lobule. Specific frequencies, such as the gamma frequency, have demonstrated beneficial effects on memory under high cognitive load. However, tACS has technical limitations, including uncomfortable sensations and uneven diffusion of electrical currents within the brain, which restrict its effectiveness in deeper brain regions. Transcranial alternating magnetic stimulation (tAMS) is emerging as a potentially more precise and comfortable method. Unlike tACS, tAMS uses magnetic fields that penetrate more deeply into the brain and provide a more homogeneous distribution of induced electrical currents, allowing for more targeted stimulation. This study compares the effects of tACS and tAMS on working memory, with the hypothesis that tAMS will offer additional advantages in terms of comfort and efficacy. Cognitive performance will be assessed using working memory tasks, along with EEG signals to analyze neuronal modulations. The objective is to demonstrate that tAMS more effectively reaches deep brain regions and improves cognitive functions.
Interventions
OTHERElectrical stimulation
The experimental session lasts 2 hours and 30 minutes and includes four phases: Time 0, dedicated to training and adjustment of task difficulty, followed by Time 1, Time 2, and Time 3, corresponding respectively to assessments of working memory performance before, during, and after exposure to stimulation. Each phase includes blocks of the Sternberg task, for a total of 180 trials per session. Each block lasts 10 minutes.
OTHERMagnetic stimulation
The experimental session lasts 2 hours and 30 minutes and includes four time points: Time 0, dedicated to training and adjustment of task difficulty, followed by Time 1, Time 2, and Time 3, corresponding respectively to assessments of working memory performance before, during, and after exposure to stimulation. Each time point includes blocks of the Sternberg task, for a total of 180 trials per session. Each block lasts 10 minutes.
OTHERNo stimulation
The experimental session lasts 2 hours and 30 minutes and includes four time points: Time 0, dedicated to training and adjustment of task difficulty, followed by Time 1, Time 2, and Time 3, corresponding respectively to assessments of working memory performance before, during, and after exposure to sham stimulation. Each time point includes blocks of the Sternberg task, for a total of 180 trials per session. Each block lasts 10 minutes.
Sponsors
Clinique Beau Soleil
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* Written, voluntary, and informed consent to participate in the study * Fluent French speaker (task instructions are provided in French) * Normal or corrected-to-normal vision using contact lenses only Non inclusion Criteria: * Individuals deprived of liberty by law * Individuals under legal guardianship or curatorship * Pregnant or breastfeeding women * Presence of metallic implants in the head, implanted electronic devices, or any other metallic object that cannot be removed for the experiment (e.g. dental fillings) * History of neurological or psychiatric disorders according to the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) * History of pathology or chronic disease affecting memory or attention * Drug or alcohol consumption within the previous 24 hours
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Sternberg task | Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure) | During each trial, participants memorize a sequence of eight letters presented sequentially. They are then shown a probe letter displayed in blue and must indicate whether this letter was part of the memorized sequence. Participant performance will be evaluated based on two behavioral measures: accuracy (proportions of correct and incorrect responses) and reaction time in milliseconds. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| EEG Power Outcomes | Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure) | Absolute power of EEG frequency bands will be measured using power spectral density analysis to quantify the energy within each frequency band associated with working memory. |
| EEG Signal Regularity Outcomes (RQA) | Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure) | Recurrence rate derived from recurrence quantification analysis will be used to quantify the proportion of recurrent patterns in the EEG signal. |
| Neuropsychological data | Baseline (Day 1, before exposure) | Score from the Multidimensional Fatigue Inventory (MFI-20) will be used to assess fatigue. The Multidimensional Fatigue Inventory is a self-reported questionnaire with total scores ranging from 20 to 100. Higher scores reflect higher levels of fatigue. |
Outcome results
None listed