eli5: How are memories stored?

Question

Like are they encoded in molecules like DNA? Or in on/off patterns of bits like a hard drive? Or like an electrical signal that will be deleted if it is momentarily turned off?

In: 8

Answer 1

In neural networks, scientists used to think that each neuron stored a memory .so somewhere in the brain they thought there would be a neuron that only remembers your grandmothers face . Turns out there’s not enough neurons for the brain to work this way , instead the brain uses neural nets so for instance if I told you to think of a US president , your net for that would activate.then if I said it’s a bushy one a smaller part of the net would activate as you narrow down who I’m talking about

Answer 2

There was an experiment with grasshoppers in which a female was exposed to a spider creating a fear response.

The grasshopper offspring were exposed to a spider later and they immediately exhibited a fear response.

This is an oversimplification of the experiment but it did suggest some sort of generational/hard-wired memory ..

Otherwise memories are stored as chemical responses in human brains ..

Answer 3

Some cells in your brain have many long “arms” and reach out and hold some other cells’ “arms”. These connections, taken together, are, in fact, memories.

(For people older than 5: There are 20 billion neurons in the human neocortex, and each, on average, connects to 7,000 other neurons. These connections are called synapses.)

Answer 4

u/Arctic_Gnome,

Neurons in the brain are connected to multiple other neurons. They get excited by signals from connected neurons and send electrical impulses in turn to some or all of their connected neurons.

Impulses from a set of neurons reaching a neuron within a specific set of time are interpreted as an **input**. A neuron receiving a known input will trigger a specific set or sequence of **output** impulses. Cascades of inputs and outputs, involving billions of connections, are experienced as memories.

It is estimated there are between 85 billion to 100 billion neurons in a human brain. There are approximately 100 trillion connections between neurons.