Memory is necessary for data processing, recalling things and making decisions. Without it, we would not be able to cope with everyday tasks. Remembering is one of the important functions of the brain (the hippocampus of the temporal lobe). Often, memory refers to the storing of information in the long-term memory.

Memory can be divided into many functional types: sensory memory is divided into iconic memory (visual), echoic memory (auditory) and haptic memory (touch) according to the area of the cerebral cortex in which the sensory information is stored. With the help of sensory memory, things heard and seen can be kept in mind.

Short term (working) memory only keeps things in mind momentarily for a few seconds, just like sensory memory. The working memory can be used to remember a password or a code when we write it, for example. Long-term memory, on the other hand, is where data, memories and events are stored for a lifetime. Without long-term memory, we would have no identity of our own and no life history. Procedural memory, which is a part of the long-term memory is responsible for knowing how to do things, such as accomplish movements.

Learning refers to the process of moving things into long-term memory. Sleep, memory and learning are all interrelated. Dream is known to have a learning-enhancing effect, because during sleep the so-called memory traces are strengthened. Memory traces are created when information is memorized during the learning process. In this way, permanent new routes and connections to the neural network are created, as the communication between neurons changes permanently.