How do different areas of our brain have specific functions if they’re all made up of the same cells?

Question

Title.

In: Biology

Answer 1

Amazing question. Different areas of the brain often do have different kinds of cells. Here is a small sample of some of the many different kinds of neurons from different parts of the brain:

* [spindle neurons](https://en.wikipedia.org/wiki/Von_Economo_neuron) in the frontal lobe
* [giant pyramidal cells](https://en.wikipedia.org/wiki/Betz_cell) in the motor cortex (also frontal lobe)
* [place cells](https://en.wikipedia.org/wiki/Place_cell) and [grid cells](https://en.wikipedia.org/wiki/Grid_cell) in the hippocampus
* [Purkinje cells](https://en.wikipedia.org/wiki/Purkinje_cell) in the cerebellum
* [magnocellular cells](https://en.wikipedia.org/wiki/Magnocellular_neurosecretory_cell) and [parvocellular cells](https://en.wikipedia.org/wiki/Parvocellular_neurosecretory_cell) in the hypothalamus
* [dopamine neurons](https://en.wikipedia.org/wiki/Pars_compacta) in the substantia nigra
* [serotonin neurons](https://en.wikipedia.org/wiki/Dorsal_raphe_nucleus) in the dorsal raphe nucleus
* [acetylcholine neurons](https://en.wikipedia.org/wiki/Nucleus_basalis) in the basal forebrain
* [norepinephrine neurons](https://en.wikipedia.org/wiki/Locus_coeruleus) in the locus coeruleus

But I think I know what you mean. The way I would ask this question would be, “How do different parts of the cerebral cortex have different functions if they’re all made up of the same cells ([pyramidal cells](https://en.wikipedia.org/wiki/Pyramidal_cell))?”

The simple answer is that the function of an individual cell in the cortex depends on its inputs and its outputs. To see the function of a single neuron, you would notice what cells it receives input from, and also notice what cells it connects to. If you took some neuron out of a circuit and then re-connected it somewhere else, you would change its function. Imagine two identical neurons. One receives input from the eye and sends output to the brain stem. The other receives input from the ear and sends output to the cerebral cortex. These two neurons will have very different functions, even though they’re basically the same.