Brain plasticity refers to the brain's ability to mold itself in response to various environmental stimuli and brain injury. It entails the structural and functional changes that can take place in the brain cells, in relation to its synaptic connections with other brain cells as well as on various neuro-chemical changes taking place within the cells. Brain plasticity can also be described as the science which explains how the brain heals and grows even during adult life. This article will shed light on the mounting evidence towards the brain's inability to remain static and therefore the changes that take place in the adult brain.
In an article published in the Nature magazine on April 3 1997, a researcher from the Rockefeller University states that, “"...significantly more new neurons exist in the dentate gyrus of mice exposed to an enriched environment compared with littermates housed in standard cages." It argues that the findings contradict the previous belief that the adult brain has a fixed set of neurons and connections from early life and that it cannot adapt or grow during the adult years.
Based on the research evidence, it is believed that there are two types of modifications that can take place in the adult brain through learning. These are a change in the internal structure of the neurons, particularly at the site of synapses, and an increase in the number of synapses between the neurons.
At the same time, researchers have found that by the time a person reaches 40 years, they start to lose around 1000 neurons each day. However, one should not worry much as there are about 100 billion neurons in the brain. Apart from this, the losses can be minimized or prevented through continuous stimulation of the brain by learning new things, recalling or even engaging in brain teasing activities. The reason for this is perhaps when a particular neuron is stimulated from time to time, the inhibitory influences on the neuron from the surrounding neurons and from the intracellular fluid itself could be minimized whereas the exhibitory influences could be optimized to sustain the cells continued function.
In relation to the growth of the brains functionality, it is interesting to note the research studies done by Leif Finkel and Gerald. M. Edelman of Rockefeller University. They argue that the neurons in the brain act as a network rather than as individual signal processing units and when the same pattern of stimulations tend to happen over and over again, the connections between these neurons become stronger and stronger. At some point, the area in the brain containing the particular neural network becomes specialized in processing similar patterns of signals or functions. Thus, in the adult brain, such developments or re-enforcement continue to take place and therefore the adult brain does not remain static in relation to its functional ability.
In the event of a brain injury, scientists believe that the surrounding nerve cells near the damaged area will undergo functional and structural changes that may provide the person with an alternate route of signal processing. However, as proved by the slow recovery process of a patient following serious brain injury, these processes are slow and require persistent training and adaptation to gain at least partially effective.
In an article published in the Science News, researchers have uncovered that in mice, inhibiting the birth of new cells in the brain actually inhibits the new learning that could have taken place following an induced brain injury. The mice with the ability to have newborn cells in the brain were able to negotiate new learning in a similar post-injury state.
Thus, it brings scientists to the conclusion that the adult brain is not ‘static’ in its growth and the development of its functionality having continued stimulation and learning can actually slow down the degeneration process that may take place in the aged brain.