The baby boomers are getting older. Their pensions and healthcare will exert an enormous strain on European, north American, East Asian and Australian economies over the next few decades. Advances in medicine and medical technology continue to reduce blood-pressures, patch up hearts, extract cancers and extend life expectancy worldwide, but the brain, it turns out, does not yield to traditional methods, and effective treatments for cognitive decline and neurodegenerative diseases like Alzheimer's remain elusive. In the US, the annual cost of care for sufferers of Alzheimer's is expected to exceed the total current healthcare budget ($1 trillion) as 10 million baby boomers develop the disease (Nixon et al, 2008; Alzheimer's Association, 2008).
There is, however, one highly effective preventive treatment: heavy physical exercise cuts one's risk of stroke and neurodegenerative disease in half (Medina, 2008). Heavy, regular physical exercise improves blood supply to the brain, eliminates free radicals and stimulates the generation of new neurons. In the coming decades, 500 billion dollars or more could thus be saved each year in the US alone if every baby boomer exercised daily. The problem of course is that exercise is difficult and people are sedentary, so sedentary in fact that we are faced with a looming obesity epidemic that compounds the problem of age-related cognitive decline. And there's no way of using modern medicine to improve people's motivation to engage in physical exercise, right?
Wrong. A technique called rewarding brain stimulation has for decades allowed researchers to motivate rats to run (Burgess et al, 1991), lift weights (Garner et al, 1991) and learn other behaviours (Hermer-Vasquez et al, 2005). Here's how it might work in people: A person needing help to exercise would go to a hospital or a private clinic to be fitted with a deep brain stimulation implant capable of activating his reward system (the dopamine system). He would then be able to plug himself into specially designed exercise equipment that would reward him for exercising; a pulse of rewarding electrical current for each stroke on a rowing machine for instance. The self-stimulation experience would not be one of extreme elation but would be sufficiently pleasant to make him want to do about an hour of exercise every day.
Does it sound extreme? Dangerous? Keep in mind that thousands of patients are fitted with deep brain stimulation implants every year for other reasons (Schwalb & Hamani, 2008). The technique has even been used, unsuccessfully, in an attempt to reduce hunger in an obese patient (Hamani et al, 2008). Using deep brain stimulation to help motivate heavy physical exercise in people who need it to maintain their health is a logical next step. Initial polls estimate that rewarding deep brain stimulation implants will enter clinical trials by 2015 (FutureBlogger, 2008). How long can we afford to wait?
For more information about the neuroscience and ethics of rewarding deep brain stimulation, visit www.iPlant.eu.
References
Alzheimer's Association (2008) Alzheimer's Disease Facts and Figures. alz.org
Burgess et al (1991) Intracranial self-stimulation motivates treadmill running in rats. Journal of Applied Physiology 71(4), p1593-1597. PubMed
FutureBlogger polls (2008) 'When will iPlants enter clinical trials?'. poll 1 poll 2
Garner et al (1991) Intracranial self-stimulation motivates weight-lifting exercise in rats. Journal of Applied Physiology 71(4), p1627-1631. PubMed
Hamani et al (2008) Memory enhancement induced by hypothalamic/fornix deep brain stimulation. Annals of Neurology 63(1), p119-23. PubMed
Hermer-Vazquez et al (2005) Rapid learning and flexible memory in "habit" tasks in rats trained with brain stimulation reward. Physiology & Behavior 84(5), p753-9. PubMed
Medina (2008) Brain Rules. BrainRules
Nixon et al (2008 lecture) Memory concerns and the Baby Boomer generation. NYU Langone Medical Center. FORA.tv
Schwalb & Hamani (2008) The history and future of deep brain stimulation. Neurotherapeutics. 5(1), p3-13. PubMed