One line of research into treatments for neurodegenerative disorders involves spurring the brain to establish new neural connections to replace those that have been damaged or lost. This seems like an inferior strategy in comparison to trying to identify and remove root causes, one that can only delay the inevitable, but it's nonetheless a fairly entrenched field of work.
Here is an example of this sort of research - and note that as for other similar efforts there are hints that an induced increase in neural plasticity would be beneficial for cognitive function in all older individuals:
Researchers have developed a new drug candidate that dramatically improves the cognitive function of rats with Alzheimer's-like mental impairment. Their compound, which is intended to repair brain damage that has already occurred [by] rebuilding connections between nerve cells.
[The scientists] have been working on their compound since 1992, when they started looking at the impact of the peptide angiotensin IV on the hippocampus, a brain region involved in spatial learning and short-term memory. ... angiotensin IV, or early drug candidates based on it, were capable of reversing learning deficits seen in many models of dementia. The practical utility of these early drug candidates, however, was severely limited because they were very quickly broken down by the body and couldn't get across the blood-brain barrier.
Five years ago, [the scientists] designed a smaller version of the molecule [called] Dihexa. Not only is it stable but it can cross the blood-brain barrier. An added bonus is it can move from the gut into the blood, so it can be taken in pill form. The researchers tested the drug on several dozen rats treated with scopolamine, a chemical that interferes with a neurotransmitter critical to learning and memory. Typically, a rat treated with scopolamine will never learn the location of a submerged platform in a water tank, orienting with cues outside the tank. After receiving the [drug], however, all of the rats did, whether they received the drug directly in the brain, orally, or through an injection.
[The researchers] also reported similar but less dramatic results in a smaller group of old rats. In this study the old rats, which often have difficulty with the task, performed like young rats. While the results were statistically valid, additional studies with larger test groups will be necessary to fully confirm the finding.