Friday, 2 December 2011

Memory !!

Memory is the process used to acquire store and retain information that can later be retrieved. There are three major processes involved in memory. ENCODING, STORAGE AND RETRIEVAL. Memory cannot be found in one specific area of the brain as it a process nit a unitary entity.However the hippocampus is involved in the consolidation of a memory  and damage to this area can cause impairments between STM and LTM. 
Encoding is the 1st step in the creation of a memory and is rooted in the senses. Each separate sensation of an event travels to the hippocampus these perceptions of the event are then integrated and stored into one single experience.
There are many subtypes of memory illustrated in the picture below.
Storage of memories retention of information, which has been achieved through the encoding process, in brain for prolonged period of time until it is accessed by the recall process. Mmemory can be stored in STM or LTM (read further info for more on this) 
Retrieval of memories is the process of accessing stored memories. Once information has been encoded and stored in memory. It must be retrieved in order to be used.

The causes of amnesia can be divided into categories. Memory appears to be stored in several parts of the limbic system of the brain, and any condition that interferes with the function of this system can cause amnesia. The types of amnesia are
§  Anterograde amnesia, is the loss of short-term memory, the loss or impairment of the ability to form new memories through memorization. People may find themselves constantly forgetting a piece of information, people or events after a few seconds or minutes, because the data does not transfer successfully from their conscious short-term memory into permanent long-term memory. Primarily in older men, transient global amnesia causes severe loss of memory for minutes or hours.
§  Retrograde amnesia, the loss of pre-existing memories to conscious recollection, beyond an ordinary degree of forgetfulness. The person may be able to memorize new things that occur after the onset of amnesia (unlike in anterograde amnesia), but is unable to recall some or all of their life or identity prior to the onset. The affects of retrograde amnesia (RA) occurs on fact memory on a lower degree than its affects on autobiographical memory, which can be affected over the whole lifespan of the patient by RA

Further info: 
Sensory Memory Sensory memory is the earliest stage of memory. During this stage, sensory information from the environment is stored for a very brief period of time, generally for no longer than a half-second for visual information and 3 or 4 seconds for auditory information. We attend to only certain aspects of this sensory memory, allowing some of this information to pass into the next stage - short-term memory.

Short-Term Memory Short-term memory, also known as active memory, is the information we are currently aware of or thinking about. In Freudian psychology, this memory would be referred to as the conscious mind. Paying attention to sensory memories generates the information in short-term memory. Most of the information stored in active memory will be kept for approximately 20 to 30 seconds. While many of our short-term memories are quickly forgotten, attending to this information allows it to continue on the next stage - long-term memory.

Long-Term Memory Long-term memory refers to the continuing storage of information. In Freudian psychology, long-term memory would be call the preconscious and unconscious. This information is largely outside of our awareness, but can be called into working memory to be used when needed. Some of this information is fairly easy to recall, while other memories are much more difficult to access.

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