In my previous article, I outlined the first principles of stroke rehabilitation, explaining how strokes damage our brains and what measures we can take to either limit or begin to address these losses. Read on for part two in my three-part series, about how stroke rehabilitation works.
Synaptic regeneration and the resurrection of form; using knowledge to make a plan
The mainstay of brain recovery is cell conservation and repurposing of other redundant brain circuits. Redundant systems are those which may perform the function of another, and are present in most machines. This flexibility of brain structure and function is due to a property called 'synaptic plasticity', which is the brains ability to change both anatomically and chemically at microscopic levels. This is analogous to retraining staff to perform a new task, but is a little more complicated. Research has suggested various mechanisms that may compensate for lost cells, all utilising plasticity.
What happens when cell death occurs?
Upon cell death we see 'intrahemispheric lateralisation´, which is the reallocation of dead cell function to brain regions in the other side of the brain. The phenomenon of 'unmasking' means the use of back-up cells trained in similar purpose to those that have been lost.
These processes, coupled with the repurposing of local synaptic pathways, form an understudy team of cells. These cells, through repetitive stimulation and learning, will attempt to emulate the function of the dead cells. This entire process can be summarised as 'cortical remapping'; that is, shifting the brain region responsible for a function, away from the dead area to a new one.
The presence of redundant systems reflects the conservative nature of evolution and emphasises a human need for protection.
Exploitation of these systems in times of dire need shows their true value. It may be that these systems exist as an evolutionary hangover.
Although research in this field is in its relative infancy, it provides exciting insights into the brain's restorative mechanisms. The understanding of these systems allows us to create evidence-based treatments, using repetitive stimulation to 'rewire' the brain. This is rehabilitation.
Ben is a young NHS doctor in the Southwest. His interests include neurology, health communication, and medical ethics. He is also an avid advocate of compassionate care and quality improvement, running a project in the Southwest around medical humanities. Please follow and support: Dr Janaway on Facebook Dr Janaway on Twitter
The opinions expressed in this article are the author's alone and do not reflect those of the NHS or associated agencies. All facts are based on the best available evidence. The author is happy to receive questions. There are no conflicts of interest and due consideration has been given to the consequence of conclusion or interpretation.