How are memories formed in the brain?
The brain is made up of two main kinds of cells, neurons and glia. Neurons form the biological basis of mental processes such as memory, while glia have mainly a supporting role (delivering nutrients, recycling molecules, providing electrical insulation, etc.). Each neuron is connected to many other neurons through projections called dendrites and axons, forming large networks. The point where two neurons contact each other is called a synapse, and neurons are constantly forming new synapses and pruning old ones. A synapse can also become stronger or weaker over time, making the communication between the two contacting neurons more or less efficient. When we learn something, or form a new memory, the brain stores this new information by changing the strengths of some of the synapses. Thus, memories are encoded in the connections between neurons, and different kinds of memories are stored in different kinds of neurons in different parts of the brain.
A brain structure that has been identified as critical for the formation of several kinds of memories is the hippocampus, which is a small, elongated structure located inside the temporal lobe. People whose hippocampus is damaged, due to stroke, infection or brain surgery, lose the capacity to form long-term memories. They can remember things for a few seconds, but as soon as they get distracted by something else, the memory disappears completely. They can remember things that happened and things they learned before their hippocampus was damaged, but cannot remember anything that happened since. This condition is called anterograde amnesia. Neuroscientists think the hippocampus participates in memory formation by facilitating the changes in the synapses between neurons in different parts of the brain.
The information crosses the brain through a system that encodes it. Information storin process involves a number of changes in the brain and in the whole human body. Synapses codify information, "consolidate" memories and place the information in the appropriate area of the brain.
Formation of the synapses of this type requires to the human body to produce proteins. This process is like the one of strengthening the muscles, by eating protein. More specifically, all memories are recorded in the brain by producing proteins.
The proteins, which are necessary to store the information in the brain, have to be issued. For this reason, neural RNA has to be activated. This thing is possible in certain situations, only.
When information enters the brain, a thought of ours, an external stimulus, a picture or a melody, certain synapses are activated. At the same time, one of the proteins that protect nerve cells is destroyed. When this protein is fragmented, RNA suddenly becomes active and synthesizes a new protein that maintains the new formed synaps.
Memory is the ability to remember and recall something that is known or experienced. We do not know the exact processes taking place in the brain during the process of memorizing. What is known about these processes is that storing new memories involves both chemical changes in nerve cells of the brain and changes in their physical structure. When a person stores new memories, these physical and chemical changes take place in a section of brain called hippocampus, which is a part of the cerebral cortex, which controls most higher brain functions.