Concept
Feedback
Routing a system's output back to its input so it corrects itself — invented for amplifiers in 1927, and since found running almost everywhere in the nervous system.
From the EE side
From the neuro side
Black’s insight was that you could throw away most of an amplifier’s gain and buy accuracy with it. Biology appears to have reached the same bargain repeatedly, and usually at several nested timescales at once.
Nearby concepts
All topics under Feedback
- Reward prediction error 1997 Dopamine neurons signal not reward but the difference between reward received and reward expected — an error signal, of exactly the kind a feedback controller runs on.
- Neuromorphic computing 1990 Building computation from analog devices in their physics-limited regimes and from spikes rather than clocked arithmetic, on the argument that the brain's efficiency comes from its style of computing.
- Deep brain stimulation 1987 Chronically implanted electrodes delivering continuous high-frequency pulses, which treat Parkinsonian symptoms effectively while nobody fully agrees on why.
- The Hodgkin–Huxley model 1952 Circuit theory borrowed to explain the axon as a capacitor with voltage-dependent conductances — then handed back decades later as the template for analog silicon neurons.
- The voltage clamp 1949 A feedback amplifier that holds membrane potential at a commanded value and reports the current needed to do it, which is what turned excitability into a measurable quantity.
- Programmable stimulation waveforms — Synthesising the stimulus pulse with a modular converter instead of inheriting whatever the output stage rings at, which turns shape and timing into experimental variables.