It is the ability of the mind to store, retain and recollect information. Memories are the seat of learning with the help of special senses and skills. Storing of information after being perceived depends on the way of perception. Likewise, retaining and recollecting ability depends in the interest and understanding while learnt or stored. They also depend upon the duration, nature, repetition of retrievals of information, etc. These are not the reaction of a single nerve cell in the brain, but an interaction of millions and millions of cells – just like taking a decision in a conference hall. Brain will analyse every cell’s suggestion and gives significance in storage according to the importance of the matter or information. It also helps in interpreting things with emotions or rational thinking.
- Retrospective memories – remembering past incidents, for example schooldays or college days’ memories.
- Prospective memories – planning to do things in future, i.e. schedules, appointments, etc.
- Short term memories – are just like temporary files in computer. For example – superficial reading – it will be remembered for an hour or so if not, for that day and not more than that. Some people use to forget the food they had just two hours ago. It will be given less importance in the brain. So, like erasing a board, short-term memory will be erased often after completing the work or act. These short-term memories are lost in case of dementia or Alzheimer’s disease, so they find it difficult to do any activity.
- Long time memories – are like stored files in the computer. They can be retained and recollected for a prolonged period, even for life. These long-term memories can be lost after a head injury, mental shock, tragedy/disaster (post-traumatic stress disorder), stroke, etc.
- Global amnesia – losing entire memory
- Anterograde amnesia – cannot remember things from the start-up of complaints
- Retrograde amnesia – cannot remember things before the incident or complaints start-up.
- Mixed amnesia – losing past and present memories
- Psychological or emotional amnesia – lose of memory due to psychological trauma
- Source amnesia – know things, but could not give evidence from where he derives it
- Lacunar amnesia – loss of memory to single or specific thing/event
- Alcoholic amnesia – loss of memory due to excessive intake of alcohol
It may be a
- Physiological process occuring due to ageing or malnutrition or vitamin A, B1, B12 deficiences. These types of decline in memory will always be in slow progression.
- Pathological process occuring due to hydrocephalus, tumours, stroke, thyroid dysfunction, Down’s Syndrome, etc., as after any disease. These will most often haverapid onset.