How the Brain Creates Memories
Learning and forming new memories is an incredibly complex and fascinating process in our brains. The human brain consists of 100 billion specialized cells called neurons that are constantly sending signals and communicating to each other. Each of these neurons can have up to 10,000 connections with other neurons. These points of connection are called synapses. At synapses, active neurons release neurotransmitters that travel across the narrow gap between the neurons and bind to specific receptor molecules on the neighboring neuron (Figure 1). These synaptic connections form networks of neuronal circuits that underlay all brain function including memory making.
These intricate neuronal circuits are constantly modified during life by experience. This constant change in the synaptic communication between neurons is called synaptic plasticity and is critical for higher brain function including learning and memory.
So how do we learn something new? We learn by having experiences, whether it be studying history or learning a new language. We bring this new information into our brains through our senses. These sensory experiences are the raw ingredients for making memories. Experiences actually sculpt the circuits in the brain by engaging synaptic plasticity forming new circuits that encode the experiences.
Learning something new causes new neuronal connections and new circuits in specific brain regions. These newly formed circuits actually house the electrical fingerprint of an experience. When we recall a memory we re-engage these same circuits to replay that experience. One of the most fascinating areas of memory research now is how these circuits encoding strong memories can be maintained for decades.