Upgrade your mind.

Neurofeedback is a form of biofeedback that uses real-time measurements of brain activity — in our case EEG — to help a person learn to shift their own brain state. Sensors placed on the scalp pick up the electrical activity of the cortex underneath. That activity is processed into something the person can perceive: a sound that gets louder, a video that plays more clearly, a visual that brightens when the activity moves in a target direction.

The mechanism is operant conditioning. When the brain produces more of the desired pattern — say, a steadier rhythm in a certain frequency band — the feedback rewards it. Over time, that pattern becomes easier to produce. The person isn't told how to change their brain activity, and they usually can't describe what they're doing; the learning happens below the level of conscious strategy.

Mindchord is a lightweight neurofeedback app designed to be used by clients to complete neurofeedback sessions set by providers. The app comes in two parts: The neurofeedback app, which clients take home to complete sessions using portable EEG headsets, and the Provider Console, which providers use to set protocols and monitor clients. Providers set protocols based on what the client wants to address and any readings or examinations they perform (see Technical Feedback Info for more details about what settings can be configured by providers). The neurofeedback app offeres a variety of feedback types, including preset video feedback, local video feedback, and interactive visualisations.

Mindchord is still in closed beta, so updates are being made regularly. If you are interested in joining as a client or provider, please reach out to us - we would love to answer any questions you have or add you as a beta-tester.

Each session begins with a short calibration period in which Posttrain records the brain's natural activity in the target frequency bands to establish a personal baseline. Once calibrated, the app continuously measures your live brainwave power, (using Welch's method to estimate the spectral density of the EEG signal, with artifact rejection to discard moments contaminated by blinks, jaw movement, or electrode noise), and compares it against the user's baseline as a z-score (how many standard deviations above or below their resting state they are right now).

Feedback runs throughout the session, reflecting whether the user is currently above or below the protocol's threshold: the longer they stay above, the more the feedback intensifies, and the longer they stay below, the more it fades — reinforcing sustained self-regulation rather than fleeting peaks.

Protocols can combine up to two bands at once (for example, increasing one frequency while decreasing another), and clinicians can configure which electrode drives the feedback — any of the Muse headband's standard channels (TP9, AF7, AF8, TP10) or the optional AUX electrode plugged into the headband — along with an optional reference channel for software re-referencing to better isolate the region of interest.