Final answer:
Neuroplasticity enables the brain to form new neural connections, while neurogenesis, the birth of new neurons, continues into adulthood, with the hippocampus being a primary site. Exercise promotes neurogenesis, enhancing learning and memory, while stress hinders it. The limited replacement of lost neurons in adults influences research on neurological diseases.
Step-by-step explanation:
Neuroplasticity and Neurogenesis
Neurons and neural pathways are dynamic and can change throughout our lives. This adaptability of the brain is known as neuroplasticity. Neuroplasticity allows for the creation of new synapses, the pruning of underutilized ones, and alterations in glial cells. Notably, it enables changes in brain structure in response to personal experiences, developmental processes, and in cases of injury, as shown in Bob Woodruff's recovery. Furthermore, the phenomenon of neurogenesis contradicts earlier beliefs that we are born with a fixed number of neurons. Instead, it's now understood that the birth of new neurons, neurogenesis, continues into adulthood, with about 1,000 new neurons forming in the hippocampus every day—a region associated with learning and memory.
Neurogenesis is particularly influenced by environment and behaviors. Research has shown that activities such as exercise increase the survival of these new neurons, thereby enhancing learning, while stress has a detrimental effect. Despite the potential of neuroplasticity and neurogenesis, when neurons die, they are not typically replaced in significant numbers in adults, limiting the brain's capacity for regeneration when compared to other tissues. This presents challenges in treating neurological conditions such as Alzheimer's, stroke, and epilepsy, where significant neuron loss occurs.