A team of researchers is close to developing a drug that might help people with Parkinson’s and Alzheimer’s
Anthea Garman
Human beings will live longer in the 21st century. But the bad news is that they will suffer more from brain denegeration diseases such as Alzheimer’s and Parkinson’s.
But, says Oxford University neuro- pharmacologist Susan Greenfield, “We’re on the case.”
Greenfield and her team at Oxford have made some slightly “heretical” conclusions about neuro-degenerative diseases and are hoping to soon have a drug which will act directly on the area of the brain causing the problem.
Speaking at Rhodes University last week, as part of the international lecture series of the Sasol Science Festival organised by the Grahamstown Foundation, Greenfield outlined her findings so far. They are that:
l Alzheimer’s and Parkinson’s might be different manifestations of the same cause;
l the cause may be in the brain stem and not the cerebral cortex; and
l it might be possible to target the brain stem and the cause with a drug.
Tracking the enzyme acetylcholinesterase or ACHe, Greenfield’s team have found it in strange places in the brain doing things not expected. “It has an alter ego,” says Greenfield.
Other researchers have shown that ACHe can destroy the neurotransmitter acetylcholine, leading to memory loss and the non-transference of brain messages. But the enzyme is found in areas not conforming to this picture.
This has led to a surprising conclusion.
It goes like this: the areas that we know are affected by degenerative diseases are in the cerebral cortex, areas that cannot regrow brain cells. The brain stem by comparison is a “global system” and can regrow. It seems that the brain stem realises that other areas of the brain are dying and starts to release ACHe in order to get cells to regrow. The ACHe (in its alter ego role) makes cells take up calcium – which is very important for the growing brain of a child, but is toxic in an adult brain. The calcium injection, paradoxically, causes more death and devastation.
“Neurodegeneration seems to be an aberrant form of development,” Greenfield says.
The good news is that this process could be interfered with. While it would be dangerous to block the calcium intake – “that would have too many side effects” – a drug could be developed to “modulate calcium entry and thereby stabilise cell loss”.
Greenfield thinks it might be possible to stop these diseases in their tracks if everyone over 60 were to go for regular brain scans and be put on this drug once degeneration is detected.
Her research team has taken out a patent and is now trying to develop this drug.
Greenfield is director of the Royal Institution of Great Britain and a strong proponent of taking science to the people. She has recently made a six-part series on the brain and mind for the British Broadcasting Corporation.
She started out studying philosophy at Oxford in the 1970s. But she had to take a co-major and landed up doing psychology. Philosophy started to bore her because it was linguistic, but psychology – which had “an experimental scientific slant” – started to become very gripping.
She says she wanted to answer the “big questions”. What is individuality? What is consciousness? What is mind? Because of this she then moved into pharmacology where she could get more deeply into the workings of the brain.
The influence of both science and arts shows in her approach to her subject. She has no hesitation stepping on to philosophers’ turf when she announces “the mind is the personalisation of the brain”. (An opinion, a listening philosopher points out, that is not shared generally by her peers.)
Greenfield gets very animated when she talks about the ability of the brain to get better and better with age – “unlike the body which will go the way of all flesh”. This opinion is based on the brain’s amazing hardware – neurons, dendrites and the connections that the stimulated brain can make at will, despite the fact that its cells will die and not be replaced.
The human brain is incredibly “plastic. It can learn and adapt, which allows us to shift away from the genetic imperative.”
Although she works with a lot of people suffering neurodegeneration, Greenfield is upbeat about the future of the mind.
Mind is the dynamic result of the connections that the brain has made out of individual experiences. Through experiences the growth of connections becomes the growth of the brain.
“The mind is the personalisation of the brain, because only you will have your experiences. Not even a twin – who is a clone – will have exactly the same experiences.
“The brain will be the victim of a dramatic makeover in this new century,” Greenfield says. Because we will be living healthier and longer lives, we will have more time on our hands and will be using it to “introspect much more – asking what is the meaning of life? And expecting happiness much more.” Consequently this could also give rise to much more depression.
Very shortly the human genome will be mapped, and we will know what every gene “does”, says Greenfield, putting quote marks on the last word.
While there are single genes which dictate particular physical characteristics, it will be impossible to say “this is the gene ‘for’…” when it comes to human behaviour.
While there may be a million genes in the body the brain has 10 000-trillion connections, all developed through environment and experience. Nurture is that powerful for human beings.
There are two things Greenfield is not upbeat about: drugs and virtual reality.
The recreational drugs we indulge in as a species affect our brain connections. The reason why our brain is fooled by them is because they act like neurotransmitters. But instead of doing specified things in specific areas they “flood the brain” and overload it. She worries about the damage to those all- important brain connections.
Likewise, virtual reality can be an all- pervasive visual and auditory brain experience. Greenfield speculates that the reason why the brain makes so many connections is because we give it clues that it builds an entire, personal world out of – “the excitement between the ears and behind the eyes”.
Again, if the brain is flooded with a totality, will it bother to do any work itself?
“What will this do to imagination?” she asks. “What distraction will it cause if we are trapped always in the present moment dependent on immediate sensation? We fear cloning but we should be more afraid of what silicon is doing to our carbon.
“There’s a world of difference between information and knowledge. It’s not for nothing that we consider wisdom synonomous with age.”