Understanding Learning and Memory
What’s your new geometry teacher’s name? How do you get to your friend’s house? Where did you put your smartphone? Have you noticed that practice makes you play the piano better?
Every day, we learn and remember things that we experience in our lives. If we didn’t, we would get lost, not be able to sing along to our favorite song, and not pass that important midterm exam.
But how do we learn new things? And how does the brain store the memories so that we can recall them at a later time?
By studying the process of learning and memory, neuroscientists hope to be able to find treatments for those who lose their memories because of aging or diseases like Alzheimer’s. We may also be able to help those who suffer anxiety and depression that are triggered by bad memories from traumas like childhood abuse, car accidents, or war. We might also help people in drug abuse recovery stay off drugs by extinguishing memories that stimulate their desire to seek and take more drugs.
A Look at the Hippocampus
Neuroscientists are learning more about the process of learning and memory by studying the hippocampus, a brain region involved in forming and retaining memories. Neuroscientists don’t know exactly how learning and memory occur in the brain, but whenever learning occurs, neurons in the hippocampus become active. Learning is thought to be due to an increase in the activity between many neurons that communicate with each other.
How do neurons communicate? When a nerve impulse reaches a neuron, the neuron is activated and releases a chemical, called a neurotransmitter, at the synapse, or the place where two neurons connect. The neurotransmitter crosses the synapse, where it connects to a receptor molecule located on the adjacent neuron. This binding of the neurotransmitter activates the second neuron, which sends a neurotransmitter to the next neuron, and so on. This process continues from neuron to neuron as the nerve impulse travels throughout the brain.
Neuroscientists have discovered that when you are not learning, a nerve impulse will cause a neuron to have a low level of activity, but that during learning, the electrical activity between two neurons will be increased. This phenomenon is called long-term potentiation or LTP, and researchers have found that animals do not learn when LTP is blocked.
One of the goals for neuroscience research is to be able to manipulate LTP and, as a result, also influence learning and memory formation. Someday neuroscientists hope to be able to help your grandmother find her glasses and purse, to reduce the stress and anxiety that is felt by those who have memories of traumatic events, and even to extinguish the memories that cause a person to want to continue to use drugs.
Roger Sorensen, Ph.D., M.P.A., is a NIDA program official who directs a grant program that supports basic science research on the physiological effects of drugs of abuse on the brain and nervous system. He was trained in neurochemistry and expects that someday scientists will be able to determine how this complex organ known as the brain makes us think, feel, and be who we are.