Neurochemical basis of memory
Memory is a complex and yet not sufficiently studied process, including the phases of capturing, storing and retrieving incoming information. All these phases are closely related, and they are often very difficult to distinguish when analyzing memory functions.
Types of biological memory:
4. Neurological (it is sometimes called mental or individual).
At present, neurological memory is divided into three stages:
1. Short-term memory (duration from several milliseconds to several minutes).
2. Intermediate (from a few seconds to several hours).
3. Long-term memory (years, decades and throughout life).
Neurological memory has a complex system organization and does not have strict localization in certain areas of the brain. According to modern ideas, traces of memory (engrams) are fixed in the brain in the form of changes in the state of the synaptic apparatus, as a result of which the preferential excitation of certain neural pathways arises.
After the perception of information, in the process of its capture and fixation, a series of successively changing neurochemical processes occur in the brain. At the first stages, in the stage of short-term memory, there are changes in the “fast” synapse functions associated with the release and shift of the concentration of “classical” and peptide mediators. Later, for a period of several seconds to several days, a wide range of neurochemical processes involving changes in the composition and structure of neurospecific proteins, in particular changes in the degree of their phosphorylation, and modification of the synthesis of RNA, takes place.
For the formation of lifelong long-term memory, a constant synthesis of new biopolymers is necessary, which can be implemented in the case of stable rearrangements in the functioning of the genome sites. The latter can occur as a result of either structural changes in DNA, or the formation of stable cycles for the continuous synthesis of repressors or derepressors of transcripts. It is also possible that immunological mechanisms are involved in the formation of long-term memory, thanks to which antibody-like compounds are synthesized in the brain that can for a long time modify the activity of synapses in certain nerve pathways. In the mechanisms of memory formation, both “classical” mediators and a large number of neuropeptides that function as mediators and neuromodulators participate.
The main questions to be answered in the study of molecular mechanisms of memory are: what metabolic changes occur in neurons when they meet with an external stimulus, which allow the stored information to be preserved for a certain (sometimes long) time; in what form the received information is stored; how is it analyzed?
In the process of active learning that occurs at an early age, there are changes in the structure of neurons increases the density of synaptic contacts, the ratio of glial and neuronal cells increases. It is difficult to distinguish the process of maturation of the brain and structural changes, which are molecular carriers of memory. However, it is clear that for the full development of intelligence is necessary to meet the challenges imposed on the environment (think of the phenomenon of Mowgli or problems of adaptation to life in the nature of animals raised in captivity).
Neurochemical basis of memory