Ability of human mind to retain traces of past perceptions and sensations and to reproduce them as concepts and ideas is what is meant by memory. Memory constitutes experiences of the past and the present: Since there is no future experience in the present, non-existing future experience cannot constitute memory of the present.
Brain activity that leads to reflection of objective reality of the outside world begins with sensations. Brain does not react directly with the outside objects, but it acts through receptors known as sense organs which are connected to sensory centres in the frontal cortex of the brain. Brain has five sensory centres each representing the five sense organs. Sensation is the primary mental reaction induced in the cerebral cortex of the brain by different stimuli emanating from internal or external environs. The stimuli interact with sensory nerve endings:
The interaction produces sensation in the nervous system. ‘Sensation’ is the initial stage of cognitive activity which is generally termed as thinking process. By nature, Sensation is the elementary step in cognitive process: Sensation does not portray the object of information in its entirety or in its complete form. The process, by which the entire picture of an object of information is reflected, is known as Perception. Perception is the second stage of cognition. What is perceived through sensations leaves traces of images in the brain and when the encounter is over, the images become capable of being reproduced: That scenario represents what is called ‘memory’ and ‘memorization’. But at that stage, images are subtle and the memory is unstable. This can well be compared with a growing child:
When the child starts growing, its mental development also starts picking up. In the early stages of growth, the images cast in its brain are poor and unclear. As the child grows, its brain starts developing Second Signal System which is identified as speech. Then the child’s world of images gets enriched: In adulthood, perceptions become clearer and with fully developed Second Signal System that is the use of language termed as speech, the adult becomes capable of generalization and segregation of concrete images. The capability of generalization and segregation of images is Conception. Sensations, Perceptions and Conceptions undergo evaluation and judgment. And thus ‘memory’ becomes stabilized and capable of being reproduced in proper and complete order. The whole process confirms that Conception is the torch bearer of memory and memorization:
Conception is facilitated by Second Signal System of language: Language plays a key role in brain activity of humans; language makes the major difference between humans and animals. Memory can be traced to experiences which one has encountered. Experiences can be of the past or of the present. Since experience of future does not exist in the present and since experience of the future did not exist in the past either, it does not contribute anything to the constitution of memory in normal brain activity. However in abnormal brain activity through and by imaginations, it is possible for some persons to build up memory in their brain. The fundamental principle of such memories relates to different beliefs nurtured by individual human beings.
Memory of past experiences sometimes leads to different emotional and attitudinal changes in humans. These changes may relate to matters of happiness, joy, pleasure and feelings of wellness, sorrow, worries, agonies and distresses. Due to conditional situations of something or the other, the emotions and attitudinal changes affect certain section of the people very adversely. As a consequence they lose their mental equilibrium. Such persons are generalized into the category of mentally deranged persons. Mentally deranged patients need appropriate clinical treatments to bring back their cerebral functions into normalcy.