How 40 Hz Light and Sound Are Shaping Brain Longevity Research

The Rhythmic Revolution: How 40 Hz Light and Sound Are Shaping Brain Longevity Research

There’s a new frontier in brain longevity research that doesn’t start with a pill. It starts with rhythm.

Over the past decade, scientists most visibly at MIT’s Picower Institute for Learning and Memory, have been exploring whether exposing the senses to gentle, precisely timed pulses of light and sound at 40 cycles per second (40 Hz) can help the brain maintain stable function over time (Tsai & Boyden / Picower Institute).

This 40 Hz rhythm sits in the brain’s gamma band, a fast range of electrical activity (roughly 30–100 Hz) associated with higher-order mental functions like attention, working memory, and sensory integration (Buzsáki, 2006; Tsai Lab summaries, 2024–2025).

The hypothesis is simple: repeatedly giving the brain a clean 40 Hz signal through the senses may reinforce internal communication patterns that matter for long-term brain stability (Iaccarino et al., 2016; Martorell et al., 2019).

This method is known as GENUS, Gamma Entertainment Using Sensory stimuli (Tsai et al., 2016–2025).

Note: Nothing in this article is a medical claim. This is about supporting brain longevity, preserving internal organization, communication quality, and functional resilience over time.

Why 40 Hz? The Frequency That the Brain Listens To

You may ask: why 40 Hz and not 12 Hz or 80 Hz?

Biology first: Gamma rhythms around 40 Hz are closely linked to attention, working memory, and coordination between brain regions. These rhythms tend to weaken in aging brains under stress (Fries, 2015; Martorell et al., 2019; Tsai Lab, 2025).

Practicality second: Forty hertz is a frequency the brain can actually “follow.” In MIT studies, presenting mice with light flickering at 40 times per second caused neurons in the visual cortex to fire in sync at the same frequency (Iaccarino et al., 2016).

Later studies extended this to sound: simple 40 Hz auditory pulses for one hour per day over a week drove gamma activity in both auditory cortex and hippocampus, improving memory and reducing protein buildup associated with neurodegenerative stress (Martorell et al., 2019).

In short: 40 Hz is biologically meaningful and technically entrainable, making it ideal for sensory brain stimulation.

Methods of 40 Hz Sensory Entrainment

1. Visual Entrainment (Light)

Early studies used light flicker. In mouse models of age-related cognitive decline, 40 Hz light caused visual cortex neurons to synchronize and shifted biological markers linked to long-term brain maintenance (Iaccarino et al., 2016).

2. Auditory Entrainment (Sound)

Repetitive 40 Hz auditory pulses — not music, not hypnosis — drove gamma oscillations in both auditory cortex and hippocampus. Seven days of one-hour sessions improved spatial and recognition memory and reduced stress-related protein buildup (Martorell et al., 2019).

3. Audiovisual Entrainment (Light + Sound)

Combining 40 Hz light and sound synchronized activity across broader networks, including prefrontal areas (planning, decision-making) and hippocampal circuits (memory integration) (Adaikkan et al., 2019; Martorell et al., 2019).

Daily sessions of synchronized 40 Hz stimulation temporarily boosted coordinated signaling between hippocampal subregions CA3–CA1, key for forming and stabilizing memories (Paulson et al., 2025).

4. Tactile / Vibration

Early animal studies suggest rhythmic 40 Hz vibration may drive gamma-like activity, preserve motor wiring, and reduce inflammatory stress, extending the gamma effect beyond vision and hearing (Rodrigues-Amorim et al., 2024).

Takeaway: Light, sound, and touch form a multisensory method for feeding the brain a rhythm it already uses during clarity and integration.

How 40 Hz Stimulation Supports Brain Longevity

“Brain longevity” means protecting structure, preserving communication, and sustaining functional independence over time.

1. Boosting Brain Housekeeping and Waste Clearance

The brain’s glymphatic system clears metabolic waste via cerebrospinal fluid (CSF). In mice, multisensory 40 Hz stimulation increased CSF influx and interstitial fluid efflux — essentially improving waste clearance (Murdock et al., 2024).

Mechanism: 40 Hz stimulation recruits specific interneurons, influencing vascular pulsation and water channels like aquaporin-4 to pump fluid efficiently (Murdock et al., 2024).

2. Microglial Activation for Immune Support

Microglia  the brain’s caretakers  can be nudged into a more active, debris-clearing state with 40 Hz stimulation, reducing protein buildup and inflammatory stress (Iaccarino et al., 2016; Martorell et al., 2019).

3. Preserving Brain Wiring and Signal Integrity

Daily 40 Hz stimulation preserves synapses, reduces neuron loss, and maintains communication between memory and executive function networks (Adaikkan et al., 2019; Martorell et al., 2019; Paulson et al., 2025).

It also protects white matter, promotes new myelin-producing cells, and reduces inflammatory damage (Rodrigues-Amorim et al., 2024).

Summary: Maintain the wiring, maintain the signal the real essence of brain longevity.

From Lab Research to Everyday Use

MIT scientists Li-Huei Tsai and Ed Boyden co-founded Cognito Therapeutics to bring 40 Hz sensory stimulation into daily life.

Cognito’s wearable system delivers synchronized 40 Hz light through goggles or visors, and 40 Hz sound through headphones, translating GENUS research into at-home brain stimulation (Cognito Therapeutics; WIRED, 2024–2025).

Defining Brain Longevity in Practical Terms

Brain longevity here means:

• Preserving communication pathways in the brain (Rodrigues-Amorim et al., 2024)
• Supporting housekeeping and waste clearance (Murdock et al., 2024)
• Rehearsing coordinated activity patterns in memory, attention, and planning networks (Martorell et al., 2019; Paulson et al., 2025)

Instead of forcing the brain with chemicals, 40 Hz sensory stimulation invites the brain to strengthen its own rhythms day after day.

Not a cure. Not a stop to aging. Simply a method to help the brain defend its internal organization.

Current Status of 40 Hz Brain Stimulation Research

• The brain is rhythmic and can respond to external rhythms noninvasively.
• Forty hertz light, sound, and possibly touch appear to be a “dialect” the brain listens to across multiple regions (Iaccarino et al., 2016; Martorell et al., 2019; Tsai & Boyden ongoing).
• Large human trials are underway to test the durability of daily 40 Hz stimulation (ClinicalTrials.gov NCT05637801; Cognito Therapeutics HOPE trial updates, 2024–2025).

40 Hz rhythmic sensory stimulation, flicker for the eyes, pulses for the ears, and vibration for the body is now one of the most closely watched frontiers in noninvasive brain longevity research (Tsai Lab review, 2025; Rodrigues-Amorim et al., 2024).