Brain changes is not a technical term with a specific reference. As such, it can refer to negative changes in the brain such as atrophy, dementia, strokes, seizures, and tumors and all the effects they cause. It can, however, also refer to positive changes in the brain such as learning, forming memories, and normal development.
Positive brain changes are part of the normal development of human beings. Although the neural plate—the first step in neural and brain formation—occurs in day 16 of an embryo’s development, the brain does not reach its maximum weight until around age 19–21. During that time, change is ongoing.
Besides the normal physical development of the brain, there are other positive changes that occur. The term neuroplasticity captures the fact that learning and remembering results in physical changes in the brain. New neural pathways may be formed and additional synapses may be formed between neurons. That is, learning and forming memories causes physical changes in the brain.
Negative brain changes may be the result of aging, injury, or disease. Aging brings about synaptic pruning, the elimination of weaker synaptic connections, and the death of neurons that are not involved in receiving or transmitting information. Neuroinflammation is also associated with aging, irrespective of disease, but it is also a physiological brain change that is tied to specific neurological issues, such as stroke, multiple sclerosis, meningitis, and brain trauma.
Dementia—which can be caused by a number of different things, such as Alzheimer’s Disease, Parkinson/Lew Body, stroke, head injury, multiple sclerosis, alcoholism, syphilis, neuroAIDS, chronic hypothyroidism, Huntington’s disease, or Vitamin B12 deficiency—is closely tied to degenerative brain disease. This is characterized by a number of brain changes, such as beta-amyloid plaques, neurofibrillary tangles, and cerebral atrophy in most people. In January, 2009, a new study showed that the brains of people who have diabetes and develop dementia such as Alzheimer’s differ from people without diabetes who develop Alzheimer’s. Instead of the beta-amyloid plaques, those with diabetes displayed arteriole injury and nerve tissue swelling.
Other negative brain changes result from addiction, which causes changes in brain chemistry. Post-traumatic stress disorder (PTSD) and depression also create brain chemistry changes. The ability to affect brain chemistry is also used to good effect in pharmaceuticals that treat all three of these disorders.
Because brain structure is correlated with brain function, injuries to specific parts of the head may result in very specific brain changes that result in very specific brain function deficits. For example, damage to the left temporal lobe may result in aphasia—loss of the ability express or understand spoken and/or written language—while damage to the left parietal lobe may result in apraxia—loss of the ability to sequence movements into a task.