model organisms in neuroscience

A model organism is a creature that scientists study closely as a stand-in for life in general — including for us — rather than only for its own sake. The bet behind the choice is simple: brains across the animal world are built from the same kind of cells, called neurons, wired together at the same kind of junctions, called synapses, and run on the same basic electrical and chemical tricks. So a rule discovered in a worm or a fly often turns out to hold in a mouse, and sometimes in a human. By picking a few well-behaved species and getting to know them inside out, researchers learn general principles of how nervous systems are put together and how they work.

Each favorite species is chosen for a particular advantage, the way you would pick the right tool for a job. A tiny roundworm has so few nerve cells that every single connection between them has been mapped, giving a complete diagram of a working nervous system. A fruit fly is cheap to raise and easy to edit genetically, so scientists can switch individual neurons on or off and watch behavior change. A young zebrafish is see-through, letting its brain cells be filmed as they flash during swimming. Mice and rats carry a mammal brain organized much like our own, which makes them the workhorses for studying memory, emotion, and disease.