A) IMMEDIATE OR SENSORIAL MemorY:
It’s the storing of information during some seconds, coming from the different senses that extend the duration of the stimulation; this process makes easy the processing in the short term memory (operative memory). The most studied stores have been those of the senses of the sight and the ear.
The iconic store is in charge of receiving the visual perception. It’s considered a deposit of liquid of great capacity in which the stored information is an isomorphic representation of the reality of character purely physical and no categorial (the object hasn’t been recognized yet). This structure is able to maintain nine elements approximately, for an interval of time very short (around 250 milliseconds). The elements that finally will be transferred to the “Operative Memory” are those that the user pays attention.
The echoic store, on its part, maintains stored the auditory stimulus until the receptor has received the enough information to be able to process it definitely in the “Operative Memory.”
B)  SHORT TERM memory: (Operative memory,

functional memory)
The short term memory (operative memory, functional memory) keeps the information between 15 – 30 seconds and can be extended several minutes by repetition; it’s the handling of the information that occurs by interaction of the individual with the environment. Just a hundredth part of the sensorial information can be stored; and of this, just a twentieth part is stored in a stable way and on short term during an enough time as being able to use it. For this reason, frequently it’s named functional memory. When a patient lost the short term memory, just reminds the past events, but doesn’t remember the events of the last minutes.

 

The general functions of this memory system cover the retention of the information, the support in the learning of a new knowledge, the understanding of the environment in a given moment, the formulation of immediate goals and the resolution of problems. Due to capacity limitations, when a person realizes a determined function, the other functions won’t be able to carry out in this moment.
C)  LONG TERM MEMORY: (Memory remote)
It’s the storing of the information for days, weeks, and years. It’s a storing of memories that are not used in the moment but potentially can be recovered. It allows recovering the past and using this information to fight with the present; in a sense, the long term memory allows living simultaneously in the past and in the present. It’s the structure in which are stored the vivid memories, knowledge about the world, images, concepts, strategies of acting, etc. When the patients lost their long term memory, they become unable to remember events of the remote past.
The long term memory can be declarative when it’s stored information about facts; so, when it’s stored information about knowledges about the world and their vivid experiences for each person; it represents events and happenings that reflect details of the vivid situation and not only the meaning. And about the declarative memory, also we have the semantics is when the information is extracted from extrapolate concepts of vivid situations; it’s a store of knowledges about the meanings of the words and the relations between those meanings, constituting a sort of mental dictionary. The long term memory can be processed, when it serves to store information about the procedures and strategies that allow interacting with the environment; it’s the learning of different types of skills, whose execution is in an unconscious or automatic way, resulting practically impossible its verbalization.

The episodic memory can be affected by the Alzheimer’s disease, by minimum cognitive damage type amnesic, by encephalitis, by trauma, by convulsions and by hypoglycemia. The semantic memory can be affected by the Alzheimer’s disease, semantic variant of frontotemporal dementia, traumas, and encephalitis (very common by simple herpes). Finally the processed memory is affected by the Parkinson’s disease, progressive supranuclear paralysis, olivopontocerebellar degeneration, depression and obsessive – compulsive disorders.