Don Arnold in The Conversation:
Previously, researchers focused on recording the electrical signals produced by neurons. While these studies have confirmed that neurons change their response to particular stimuli after a memory is formed, they couldn’t pinpoint what drives those changes.
To study how the brain physically changes when it forms a new memory, we created 3D maps of the synapses of zebrafish before and after memory formation. We chose zebrafish as our test subjects because they are large enough to have brains that function like those of people, but small and transparent enough to offer a window into the living brain.
To induce a new memory in the fish, we used a type of learning process called classical conditioning.