Brain Plasticity, Synaptic Plasticity and Neurogenesis - Essay Example

Brain Plasticity Brain plasticity is term used to refer to the concept that states that an individual’s nervous system has the ability to alter its functionality and construction throughout the time period he is alive and this alteration occurs due to his/her interaction with the diversities of the environment (Cotman, 2002, p.295). This terminology is utilized in the fields of psychology and cognitive sciences but providing a specific definition to this term is quite difficult because changes and alterations of the nervous system occurs at several different levels which range from the level of molecular events, for example: alterations in behavior as well as expression of the gene. There are different forms of brain plasticity which range from synaptic plasticity to functional compensatory process to neurogenisis. Synaptic Plasticity When a person indulges in the process of learning and practicing new things, the brain maps and stores all the perceived information via neuronal circuits (Huerta, 1993, p.724). New neuronal circuits develop via conduction of impulses through the pathway of inter-linking neurons that communicate and make way for the passage of impulses with the help of synaptic junctions present at the axonal and dendritic ends of neurons. When the brain initially acquires an absolutely unknown knowledge about a certain perception, it acts like a stranger and takes some time to understand and become familiarized with the specific knowledge. An unrecognized stimulus for the brain acts like a foreign body in the body. Initially, when a new neuronal circuit builds up in the brain, the transmission of signals at synapses of neurons takes times, and it is the first time when a new pathway forms, like a new country on the globe. Thereafter, with every repetitive experience with the same series of events, the flow of synaptic transmission via the same pathway becomes more and more rapid. This strengthens the memory retention regarding the learning process about something for which already a new circuit has been established. This repetitive transmission of impulses via the same synaptic pathway, including multiple neurons, enables temporary short term memory conversion to long term permanent memory reservation regarding any aspect. For instance, when a person first encounters a new species of bird, many processes start functioning simultaneously, and are destined to target different areas of the brain that interconnect via adjacent neurons to form a new neuronal circuit concerning the recognition of that bird. Eyes perceive all the dimensions of the bird’s appearance; its color, shape of beak, eye, and its size. All this information is conveyed via the optic disc tract to the visual cortex of the brain for the formation of complete picture of the bird. Side by side, auditory cortex notes the voice and name of that bird. On second exposure with the same bird species, the brain instantly starts regulating all the processed information. The neuronal pathway first developed about all bird’s characteristics, becomes activated and passage of same signals begin via synaptic transmission. This way, a person immediately recognizes that bird when he/she observes it for the second time. Familiarity with a certain stimulus is must for efficient synaptic transmissions. Synaptic plasticity is an amazing phenomenon that is developed due to repetitive episodic transmission of impulses via the synaptic junctions involved in a particular neuronal pathway formed. Neurogenesis Since many years, scientists had a very strong belief with authentic reasoning that neurons do not regenerate once they have degenerated (Anderson, 2005, p.1382). According to researchers in the late past, there was no evidence of existence of birth of new neurons in the brain, and the neuronal cell necrosis which once occurred in the brain led to death of that brain area, completely affecting that part of body to which the related brain area was associated to, as indicated by symptoms of hemiplegia, paraplegia, quadriplegia, slurring of speech, loss of memory and many more disorders. But since 1944, absolutely a new phase revived in the way of constant researches. Researches made thereafter, began to reveal the existence of the reality of neurogenesis. But acceptance of this fact wasn’t that easy, and elimination of the belief of impossibility of new neuronal birth after childhood, took several years to wipe off. Researches regarding neuronal genesis have established in the recent years, along with gradual acceptability that new neuronal cell birth takes place from time to time in the fully developed brain also. The fact of irreversible brain death has been left behind now. There is now a lot of active work going on this research criterion. These young neuron cells bud from stem cells present in basal ganglia, hippocampus and frontal lobes, and develop into full mature neurons having axonal body and dendritis. These new budded neurons serve the purpose of filling the spaces of brain areas that lack the needed neurons. These new neurons acquire locomotive properties in the brain and modify themselves to fulfill the function of the brain when and where required. Functional Compensatory Plasticity Thanks to science and research that everyone is aware that brain function deteriorates with age due to neuronal wear and tear and slowing of synaptic transmission (Anderson, 2005, p.1380). This reduces and impairs neurocognitive abilities. On the contrary, in some new researches, it has been amazingly identified that new information is processed in some aged people with same efficiency as in young and middle age people. But, along with it, recruitment of additional brain areas during synaptic transmission of impulses also takes place in old people. This has been justified as compensatory mechanism that enables similar cognitive capabilities. Brain plasticity is an amazing exploration of researches that includes the modification and adjustment processes conducted in the brain for compensation of functional deficit. Times are gone when people were hopeless about reversible brain deficits. It has been realized that there is always a chance of improvement due to the evidence of neurogenesis. Apart from this, new circuits are always being formed when processing of new information occurs via synaptic transmission of impulses. Repetitive transmission via same circuit pathways on exposure to the familiar information leads to achieve synaptic plasticity. References Anderson, V., Catroppa, C., Morse, S., Haritou, F., & Rosenfeld, J. (January 01, 2005). Functional plasticity or vulnerability after early brain injury?. Pediatrics, 116, 6, 1374-82. Huerta, P. T., & Lisman, J. E. (January 01, 1993). Heightened synaptic plasticity of hippocampal CA1 neurons during a cholinergically induced rhythmic state. Nature, 364, 6439, 723-5. Cotman, C. W., & Berchtold, N. C. (January 01, 2002). Exercise: a behavioral intervention to enhance brain health and plasticity. Trends in Neurosciences, 25, 6, 295-301. Read More