Dictionary

A network of brain regions active during mind-wandering, self-reflection, and unfocused thinking. The inner narrator, the rumination engine, and the source of shower-thought insight all run through it.

Same network, two modes. When the DMN runs in tight self-referential loops, it produces anxiety and rumination. When it runs loose and associative, it produces creative insight and the felt sense of rest.

Rest practices like meditation and yoga nidra measurably reduce DMN activity beyond what an active task does. They are not turning off the narrator; they are getting it to loosen its grip.

The biological principle that low doses of a stressor produce beneficial effects, while high doses are harmful. The body's adaptation to mild challenges produces strength that wouldn't develop without them.

Cold exposure, heat exposure, exercise, fasting, and sun exposure all operate via hormesis. The interval between "too little" and "too much" is where adaptation lives. The dose makes the medicine.

The sense of the body's internal state - heartbeat, breath, core temperature, gut signals, muscle tension. Maps to the insular cortex. Some neuroscientists call it the sense most people never learned.

Mapped along three measurable dimensions: accuracy (can you actually detect signals), sensibility (do you think you can), and insight (does your perception match what is actually happening). Most people score high on sensibility and low on accuracy.

Temperature contrast trains accuracy through brute signal strength. The cold won't let you feel cold and call it something else.