Hippocampal neurons

Learning and memory

The brain structures, neurons and even molecules and genes associated with memory are beginning to be identified

We are in many ways the sum of our experiences. How we act and behave depends not just on what is happening to us now but also on what has happened to us in the past. We learn and we can make memories.

Nearly all animals can learn. A simple form of learning is association – some kind of sensory stimulus is ‘remembered’ and an animal’s behaviour changes the next time it encounters that stimulus. The classic example is provided by Pavlov’s dogs, which were given food every time a bell rang. Eventually, they began to salivate in response to the bell on its own.

Human memory is more complex – in fact, we have several different types of memory, involving many parts of the brain.

Making memories

But what exactly does a ‘memory’ look like in the brain? Again, it is difficult to liken it to anything everyday such as a photograph in an album.

Memories are hard to pin down, as they involve a constellation of neurons connecting together in different patterns. Putting away a memory of Christmas Day is achieved by millions of neural brain patterns firing: some for the taste of Brussels sprouts, others for a favourite carol. The pattern remains after the stimuli disappear, and a memory is born.

In terms of mechanisms, memory making is thought to depend on neurons strengthening their connections to one another – ‘remembering’ that they have been in touch before.

Lead image:

Hippocampal neurons labelled with an antibody against the GluR1 subtype of glutamate receptors. The hippocampus is important in humans in the processes of learning, memory and navigation. GluR1 is a type of receptor common in the brain and nervous system that mediates fast synaptic transmission of signals.

AJ Irving, Wellcome Images CC BY NC ND

About this resource

This resource was first published in ‘Thinking’ in September 2006 and reviewed and updated in August 2014.

Topics:
Cell biology, Neuroscience
Issue:
Thinking
Education levels:
16–19, Continuing professional development