Although we think that the adult brain remains formed and static, we are finding that the brain changes and heals itself. Even early psychologists like William James (1890) argued that our brain is flexible and changing when he wrote The Principles of Psychology. He called this ‘plasticity’. But it took another 70 years to provide evidence for this concept.
One of the first pioneers was Joseph Altman who first discovered brain cell regeneration – or neurogenesis – in 1962.
More recently, by 1999 the psychologist Elizabeth Gould of Princeton University reported that memories can be recorded in neurons that are generated daily.
We are now in the age of brain plasticity. Neurologists and psychologist accept the idea that the brain and its function are not fixed throughout adulthood. Brain plasticity refers to the brain’s ability to change throughout life. We continue to learn because the brain keeps reorganising itself and forming new connections between brain cells. And we have come to understand the method the brain uses to change.
Donald Hebb in 1949 wrote The Organisation of Behaviour and provided us with the Hebbian Theory, which specifies that neurons that fire together wire together. If I reward a behaviour, my brain will associate that behaviour with the reward and encourage that brain connection.
In the 1950, after his father suffered a massive stroke, the New York neurologist Paul Bach-y-Rita become interested in how the brain can receive information from different organs. He invented an electrically stimulated chair.
Behind the chair, a large camera scanned the area, sending electrical signals of the image to 400 vibrating stimulators on the chair against the patient’s skin. The blind patient could ‘see’ the diffuse image from the senses on his back.
He developed this technique into a tongue sensor that goes on top of the tongue while wearing a camera that translates the image to these tongue sensors. The tongue replaces the eye and receives the feedback that the brain ‘sees’. More recently these techniques have been popularised by Michael Merzenich and Norman Doidge. They developed the idea of both positive and negative plasticity.
With half of Maltese stroke victims being older than 76, we are leaving half of the patients to die or get dementia
We all appreciate positive plasticity. We develop memories and learn new things. Our neurons and white matter that comprise our brain organise in such a way that we represent learning and experiences internally.
Representing multiple impressions of the same event under different criteria (smell, look, feel, association, importance, relevance etc.). With positive plasticity we learn new skills and improve our thinking by developing better and more efficient communication between sensory and motor pathways.
But with negative plasticity we have followed exactly the same growth but for the wrong reason. We learn how to behave in ways that are not helpful, and this is not intentional.
Negative plasticity causes an increased sense of pain, drug use and compulsive behaviour, among other negative behaviours. Pain, for example, is generated in the brain, and the only way to stop pain is to retrain the brain. Opioids lead to morphine and eventually no medication will be able to stop the brain from feeling the pain. The death of Prince and Michael Jackson is a testament to how strong the brain is in feeling pain.
Stroke offers us a window into how fast and dramatic brain plasticity can be. A stroke occurs when a part of the brain dies. It can be caused by a blood clot or obstruction of an artery (ischemia). Or, alternatively, where a ruptured artery and the neurons are flooded (hemorrhage). There are other repercussions from these two events, with an accumulation of fluid/pressure on the brain (edema) and the disruption of the sodium-potassium pump.
Of all stroke victims, roughly a third die within three months, a third do not improve and get dementia, while the remaining third improve and regain most of their lost capacities. What happens to these lucky third is important. We can learn from them about brain plasticity.
With all strokes there is a penumbra – a shadow that surrounds the dead tissue in the brain. Whether this penumbra recovers and regains back its function or dies is dependent upon how fast the brain regains control through learning. By early referral to physiotherapy, occupational therapy and speech language pathologist services, the brain heals itself.
In Malta older stroke victims aged over 70 are admitted to general wards instead of specialised dedicated stroke units which can activate brain plasticity.
With half of Maltese stroke victims being older than 76, we are leaving half of the patients to die or get dementia. Without specialised services the penumbra takes over and eventually kills the brain of the older stroke victim. Which explains why in 2014 one-fifth of Maltese stroke victims died within one month, the second highest in Europe.
With the main hospital having only four neurologists for 400 stoke victims annually, this practice of providing lesser care to older adults is justified on the basis of economics.
But the problem is deeper than that. We have an ageist view of health. Instead of referring older Maltese to therapy, we are instead shuffling them over to wards. Brain plasticity is still available for older adults. But in our ageist view we judge older adults as ready to die and fulfill this judgement by not helping their brain become re-engaged.
Mario Garrett is the author of Politics of Anguish: How Alzheimer’s disease became the malady of the 21st century. He will be delivering a talk on the ‘Politics of dementia’ at the University of Malta on February 9.