Memory is a complex function that involves multiple steps, starting with the input of the stimulus to the brain and ending with independent memory retrieval. Georgia Tech states that human memory is made up of three basic stages: sensory memory, where information is derived from touch; visual or aural; short-term memory and long-term memory. The different steps in memory retention take place throughout the brain.
The prefrontal cortex, which is part of the brain’s frontal lobe, is the region responsible for short-term memory. The Canadian Institutes of Health Research states that the human prefrontal cortex is highly developed, resulting in the complex functions and manipulation of memory. The prefrontal cortex is referred to as the “coordinator” in short-term memory, as it is involved in the ways in which memories are used. Brain imaging shows that activation occurs in the prefrontal cortex during rehearsal, an essential step in transforming short-term memories into long-term memories.
The task of consolidating short-term memories into long-term memories is performed by the hippocampus, which is located in the brain’s temporal lobe. The Canadian Institutes of Health Research note that for a memory to be consolidated, it must pass through a hippocampal pathway multiple times. The route is hippocampus to mammillary bodies of the hypothalamus, to the anterior thalamic nucleus, to the cingulate cortex, to the entorhinal cortex and back to the hippocampus. The repetition through the hippocampal pathways prevents the breakdown of the memory.
After the memory is consolidated, it is stored in the cerebral cortex, which the Nemours Foundation states is the outermost layer of the brain made of gray matter. The memory is now independent of the hippocampus, so it can be recalled at any time. Georgia Tech adds that long-term memories are subject to less decay, or loss of information, than short-term memories.