In celebrating World Brain Day this week, what better time to reflect on some of the astounding new discoveries to have come out of the recent brain science?
Almost every week new discoveries are challenging how we think the brain works, uncovering the aetiology of some of our most baffling medical problems and uncovering the potential for new treatments for those conditions previously thought to be untreatable.
1. The role of the vagus nerve in Parkinson’s disease.
A preliminary study in 2017 suggested that Parkinson’s disease (PD), (a neurodegenerative condition) might start in the gut. This was because it was noted that people who underwent a total vagotomy (a surgical treatment for ulcers) were less likely to develop Parkinson’s were 40% less likely to develop PD when followed over a 5-year period compared to those who had a selective (partial) vagotomy.
A recently published study in Neuron tested the hypothesis whether a neuronal protein called alpha- synuclein could spread from the gut to the brain via the vagus nerve where it damages dopamine producing nerve cells in the part of the brain called the substantia nigra. The findings supported the idea that the gut-brain axis is implicated, in mice at least. It’s one step closer to understanding what causes Parkinson’s and the prospect of preventative and more effective therapies.
2. Alzheimer’s disease might have a viral cause.
It’s long been believed that Alzheimer’s Disease (AD) resulted from the accumulation of two proteins, beta-amyloid and mutant tau. Many attempts to find an early biomarker or effective treatment have failed. More recently, scientists have begun to explore the idea AD might be triggered by a virus, specifically herpes simplex type 1 (HSV1) the pesky virus responsible for cold sores, that is also known to infect brain cells, especially in the higher risk group of people carrying the APOE4 gene variant. The significance being that having HSV1 and APOE4 increases the risk of AD x12.
Not only that but receiving anti-viral treatment for herpes has been shown to reduce that risk.
Professor Itzhaki believes HSV1 could account for 50% of those diagnosed with AD, and with over 150 publications now supporting the idea of an infectious role in AD involving HSV1, we may be one step closer to knowing if a viral infection is a major player in the development of AD.
It’s not that long ago that the link between cervical cancer and the human papilloma virus (HPV) was made and led to the development of an HPV vaccine.
Wouldn’t it be great if we could produce an anti-Alzheimer’s vaccine? Time, and research will tell.
3. Spinal cord stimulation to help paralysed people walk.
While too late for Superman, three men with spinal cord injury have been enabled to walk through the use of patterned electrical stimulation of the spinal cord and intensive physical therapy.
The three men had cervical spinal cord injury of long duration. In the study, they recovered voluntary control of previously paralysed leg muscles with nerve function continuing for a while even after the stimulation was turned off.
This demonstrates a neuroplastic effect, where strengthening of the brain and spinal cord had re-established connection. Something previously thought impossible.
Elsewhere Jered Chinnock who had been paralysed from a snowmobile accident in 2013, had an electrode implanted in his spine and with weeks of intensive therapy got to the point of being able to walk the equivalent distance of a football field. Four other patients given implants were reported in the NEJM as having a positive result with two of the four able to walk on their own and two regaining some functional control to stand and take limited steps.
As Kendall Lee of Mayo Clinic’s Neural Engineering Laboratories said, “this s teaching us that those networks of neurons below a spinal cord injury still can function after paralysis.”
The caveat here being every injury is unique and not everyone will respond in the same way, but this is a giant step towards more effective rehabilitation using neurotechnology. It’s a bright spark of hope for the many people living with spinal cord injury.
4. Electrical brain stimulation to improve working memory.
If you’re still relying on cryptic crosswords and online brain training to keep your memory intact, research has revealed how a gentle zap to the brain provides a temporary turbocharge to the working memory, even in younger subjects.
We use our working memory for all those bits of information we need to keep at the level of our consciousness short term, like shopping lists and making decisions and it’s well recognised it starts to decline as we age.
What was especially interesting was how the electrical stimulation improved working memory in older adults in their seventies to the equivalent level of the younger cohort of 20-year olds. Perhaps we won’t just be recharging our phones overnight to keep our brains intact and prevent cognitive decline in the future.
5. The gut-brain link and depression.
It seems everyone is fascinated by the idea of how our gut brain and the microbiome influence our health, mood and cognition. While the gut brain isn’t a brain as we know it, it’s a lacy network of 100 million neurons that lets us know when we’re hungry or full. This is now known to happen courtesy of some highly specialised hormone-producing cells recently discovered in the gut that connect with neurons in the vagus nerve acting as a direct conduit to the brain.
This is another example of how the bidirectional traffic from the gut to the brain via the vagus nerve appears to play a major role in mood disorders with vagal nerve stimulation either as an implant or used via the transcutaneous route now being used as a means to treat severe depression, epilepsy and pain.