Direction
EE → Neuro
Almost every fact we know about the nervous system arrived through a piece of electrical engineering. These are the amplifiers, electrodes, converters, and coils that turned questions into measurements.
Devices
- Neuropixels probes 2017 A CMOS shank carrying nearly a thousand recording sites with the amplifiers and multiplexers on the probe itself, which made recording hundreds of neurons at once routine.
- Cochlear implants 1991 An electrode array in the cochlea driven by a filter bank, which restores speech understanding using a couple of dozen channels where the ear has thousands.
- Two-photon microscopy 1990 Using the near-simultaneous arrival of two photons to confine fluorescence to a single focal point, which made optical recording deep in living tissue possible.
- The patch clamp 1976 A glass pipette sealed against a membrane made the current through single ion channels measurable, turning channels from inference into instrument readings.
- Microelectrode arrays 1972 Photolithographed electrode grids traded single-channel resolution for many cells at once, which is what turned single-unit recording into population dynamics.
- Electroencephalography 1929 Microvolt potentials measured at the scalp, which established that the brain has continuous electrical rhythms and states rather than only responses to stimuli.
Methods
- Functional MRI 1990 Imaging brain activity indirectly through the magnetic signature of blood oxygenation, which gave whole-brain maps of task-related activity without surgery or tracers.
- Deep brain stimulation 1987 Chronically implanted electrodes delivering continuous high-frequency pulses, which treat Parkinsonian symptoms effectively while nobody fully agrees on why.
- Transcranial magnetic stimulation 1985 Discharging a capacitor bank through a coil induces enough electric field inside the skull to fire cortical neurons, making non-invasive stimulation of a chosen region possible.
- 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.
Models
- 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.
- Receptive fields in visual cortex 1962 Cortical cells respond not to spots of light but to oriented edges at particular positions, and to progressively more abstract features further along the pathway.
- Cable theory 1959 Treating a dendrite as a leaky transmission line, borrowed from nineteenth-century telegraph engineering, which showed that dendrites compute rather than merely collect.
- 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.