Electrical Nerve Stimulation During Sleep for Memory Consolidation

Inclusion Criteria: 1. Healthy young adults (e.g., college students), aged generally between 18 and 30 years. 2. Right-handed. 3. Body Mass Index (BMI) ≤ 30 kg/m\^2. 4. Capable of fully comprehending the experimental procedures and voluntarily signing the informed consent form. Exclusion Criteria: 1. History or current presence of neurological disorders, psychiatric disorders, or brain damage. 2. History or current presence of cardiovascular diseases (e.g., arrhythmias or abnormal nocturnal heart rate). 3. Presence of depressive or anxiety symptoms (assessed by Patient Health Questionnaire-9 \[PHQ-9\] score \> 9, or Generalized Anxiety Disorder-7 \[GAD-7\] score \> 9). 4. Presence of sleep disturbances or poor sleep quality (assessed by Insomnia Severity Index \[ISI\] score \> 8, or Pittsburgh Sleep Quality Index \[PSQI\] score \> 10). 5. Any medication use within the past six months that could affect stress responses, cognitive abilities, or sleep architecture. 6. History of smoking or alcohol abuse. 7. Known skin allergies to conductive paste, medical tape, or silicone electrodes. 8. Female participants who are in their menstrual period during the scheduled experimental sessions (sessions must be strategically scheduled to avoid this period). 9. Inability or refusal to abstain from caffeine, tea, and alcohol for at least 24 hours prior to and during the experimental sessions.