About This Project
Hello! I'm Joona, and this is one of my many hobby projects.
It began as a personal Python script designed to accurately replicate the 40Hz auditory stimuli used in fascinating neuroscience research. This website is my best effort to make that experience accessible to anyone with a modern web browser.
The goal is to provide an open, transparent tool for researchers, biohackers, and anyone curious about the potential of gamma entrainment. The code is fully open-source and available on GitHub.
Consult a Professional
If you have epilepsy, a history of seizures, hearing conditions, or any neurological disorders, please consult a healthcare provider before using this tool.
Listen to Your Body
Stop immediately if you experience headaches, fatigue, dizziness, nausea, or any other form of discomfort.
Calibrate Your Volume (Critically Important)
How to Calibrate: Use the "Calibrate Volume" button on the main page with a smartphone SPL meter app (e.g., NIOSH SLM).
Suggested Exposure Limits
The idea behind this tool, called neural entrainment, is to use external sound to encourage your brain to produce more of these gamma waves.
Key Research Findings:
Alzheimer's Models (Iaccarino et al., Nature 2016)
In mouse models, 40Hz sensory stimulation was shown to reduce amyloid plaques, a hallmark of Alzheimer's disease.
Human Studies (Martorell et al., Cell 2019)
Researchers found that 40Hz stimulation was safe for humans and led to measurable changes in brain activity and preliminary cognitive benefits.
Why is Precise Timing So Important?
Neural entrainment works best with a consistent, stable rhythm. Even tiny variations (jitter) can disrupt the process. To ensure precision, this tool pre-generates the entire audio session in advance, creating a sample-accurate signal with zero timing jitter.
Stimulation Protocols:
MIT Sine Pulse
The most-studied protocol. Uses 1ms pulses of a 10kHz sine wave. Very distinct and sharp. Feels very weird when listening to it. Your mileage may vary.
Human Click Train
Uses 7ms bursts of soft, broadband noise. Many users find this more comfortable and less piercing.
Binaural Beat
Creates the 40Hz perception inside your brain by playing two different continuous tones (e.g., 200Hz and 240Hz) in each ear. Requires headphones. It's the most subtle and comfortable method. Also, prob doesn't really do anything.
Technical Features:
- • Sample-Accurate Timing via pre-generated audio buffers.
- • Built-in Safety including smooth volume ramps for sessions and breaks.
- • Pink Noise Masking to make the experience more pleasant.
- • Signal Verification to ensure the generated audio is accurate.
| Study (year) | 40 Hz modality | Subjects | Protocol (as used in paper) | Major findings (relevant to 40 Hz device) |
|---|---|---|---|---|
| Iaccarino et al., Nature (2016) | Visual flicker (LED), plus optogenetic 40 Hz in some experiments | AD-model mice (5XFAD; P301S) | Visual 40 Hz: 1 h/day for 7 days in some experiments; acute 1 h tests; effects largely local to stimulated cortex | 40 Hz entrainment reduced soluble/insoluble Aβ in visual cortex; microglia showed "engulfing" morphology; phosphorylated tau decreased after 7 days; acute Aβ drop can fade by 24 h if not repeated. |
| Martorell et al., Cell (2019) | Auditory 40 Hz; combined audio+visual ("GENUS") | AD-model mice (5XFAD; P301S) | 1 h/day × 7 days | Auditory 40 Hz improved spatial & recognition memory; reduced amyloid in auditory cortex & hippocampus; decreased p-tau; combined audio+visual produced broader microglial clustering and reduced amyloid in mPFC and across neocortex; vascular changes noted. |
| Chan et al., PLOS ONE (2022) | Simultaneous 40 Hz light + sound (home device) | Humans: mild AD dementia (pilot RCT, n=15), plus feasibility cohort | Daily 1 h at home for 3 months | Safe, feasible entrainment in cortex and some deep structures; vs control after 3 months: less ventricular expansion & hippocampal atrophy, stronger default-mode connectivity, better delayed face–name recall, improved activity rhythmicity. Exploratory endpoints; small sample. |
| Adaikkan et al., Neuron (2019) | Visual 40 Hz | Neurodegeneration mouse models (P301S; CK-p25) | Chronic daily stimulation from early disease stages (multi-week) | 40 Hz entrained V1, hippocampus, PFC; preserved neuronal/synaptic density; improved cognitive performance; transcriptomic shift toward neuroprotective state, reduced microglial inflammatory signatures. |
| Clements-Cortes et al., J. Alzheimer's Dis. (2016) | 40 Hz rhythmic sensory stimulation via sound/vibroacoustics | Humans with AD (mild, moderate, severe; n=18) | AB cross-over; 2×/week for 6 weeks (six sessions per arm) | Cognitive screening scores (SLUMS) improved over sessions during 40 Hz treatment but not with DVD visual control; effects strongest in mild–moderate AD; exploratory pilot. |
| Jirakittayakorn & Wongsawat, Int. J. Psychophysiol. (2017) | 40 Hz binaural beats (audio) | Healthy adults | ~30 min EEG; separate 20 min listening before memory test | 40 Hz binaural beats increased 40 Hz activity (fronto-temporal-central by ~15 min) and improved working-memory word recall; also mood shifts. Not disease-specific. |
| Singer et al., Nature Protocols (2018) | Methods for 40 Hz visual flicker | Protocol/methods (mice) | Hardware & exposure specs; setup in ~1 day | Step-by-step LED system, timing control, and assays; emphasizes microglial recruitment and Aβ reduction with 40 Hz; notes practical build details and considerations. |
Primary sources
1. Iaccarino, H. F., et al. (2016).
"Gamma frequency entrainment attenuates amyloid load and modifies microglia."Nature, 540(7632), 230–235. doi:10.1038/nature20587.
2. Martorell, A. J., et al. (2019).
"Multi-sensory gamma stimulation ameliorates Alzheimer's-associated pathology and improves cognition." Cell, 177(2), 256–271.e22. doi:10.1016/j.cell.2019.02.014.
3. Chan, D., et al. (2022).
"Gamma frequency sensory stimulation in mild probable Alzheimer's dementia patients: Results of feasibility and pilot studies." PLOS ONE, 17(12), e0278412. doi:10.1371/journal.pone.0278412.
Supporting literature
4. Adaikkan, C., et al. (2019).
"Gamma entrainment binds higher-order brain regions and offers neuroprotection."Neuron, 102(5), 929–943.e8. doi:10.1016/j.neuron.2019.04.011.
5. Clements-Cortes, A., Ahonen, H., Evans, M., Freedman, M., & Bartel, L. (2016).
"Short-term effects of rhythmic sensory stimulation in Alzheimer's disease: An exploratory pilot study." Journal of Alzheimer's Disease, 52(2), 651–660. doi:10.3233/JAD-160081.
6. Jirakittayakorn, N., & Wongsawat, Y. (2017).
"Brain responses to 40-Hz binaural beat and effects on emotion and memory."International Journal of Psychophysiology, 120, 96–107. doi:10.1016/j.ijpsycho.2017.07.010.
Technical reference
7. Singer, A. C., et al. (2018).
"Noninvasive 40-Hz light flicker to recruit microglia and reduce amyloid beta load."Nature Protocols, 13(8), 1850–1868. doi:10.1038/s41596-018-0021-x.