Category: Brain Research

Stroke recovery boosted by Prozac

Stroke is the third biggest killer disease in Ireland – over 2,000 people die per year – causing more deaths than breast cancer, prostate cancer and bowel cancer combined. Up to 10,000 people will suffer a stroke in Ireland this year and one in five people will have a stroke at some time in their life.

An unexpected new finding for antidepressant drugs and a very important one.

Findings from the largest study of selective serotonin re-uptake inhibitors (SSRIs) and stroke report that giving stroke patients the antidepressant drug Prozac soon after the event helps their recovery from paralysis. A total of 118 French patients were involved in the study. The beneficial effects of the drug – more improvement in movement and greater independence – were seen after three months – helping patients gain independence. This finding suggests that this already licensed drug – also known as fluoxetine – could have a dual benefit in the treatment of acute ischemic stroke – that’s where blood flow and oxygen supply to the brain are impaired.

Antidepressant drugs can help neurons to grow

One theory about how antidepressants may help brains recover more quickly from stroke is that they encourage neurogenesis – the creation of new neurons – in particular in the hippocampus – a brain region implicated in emotion especially anxiety – an emotion which can wear down even the most resilient person.

The ability of antidepressant drugs to increase neuron growth and connections – brain plasticity – is a promising pathway for treatment of patients with ischemic stroke and moderate to severe motor deficit. It’s a controversial theory and so far it only appears to hold true in young mice. In middle-aged and older mice, no such neurogenesis was observed – so there may be another mechanisms operating. 

One thing is for sure – it’s an important finding and I hope we’ll see more work on this.

Weekly Round-Up

Do you gesture while you talk? These gestures seem to be important to how we think. They provide a visual clue to our thoughts and, a new theory suggests, may even change our thoughts by grounding them in action.

In  how the brain shops, we have an exploration of the neurons associated with valuing objects, and on a related theme,  A.K. Pradeep’s  Marketing to Women examines how women shop using their instinct.

An interesting study from Dehaene et al. on how reading rewires the brain 

Latest research shows that emotional stress can change brain function. A single exposure to acute stress affected information processing in the cerebellum — the area of the brain responsible for motor control and movement coordination and also involved in learning and memory formation.

Neuroscientists at MIT’s Picower Institute of Learning and Memory have uncovered why relatively minor details of an episode are sometimes inexplicably linked to long-term memories.

Finally, are you feeling a little bored? Well new research suggests that it is not just in your head. Individual differences in sensitivity to reward, for example, are another important factor.

The neuroscience of music

I am interested in ongoing research focusing on the effects of music training on the nervous system, and have given some talks on the subject over the past few years. It is also very interesting to note from recent studies that music training has implications for neuroeducation.

Research from Northwestern’s Auditory Neuroscience Laboratory strongly suggests that an active engagement with musical sounds not only enhances neuroplasticity, but also enables the nervous system to provide the stable scaffolding of meaningful patterns so important to learning.

According to Northwestern’s Professor Nina Kraus, director of  Northwestern’s Auditory Neuroscience Laboratory “The brain is unable to process all of the available sensory information from second to second, and thus must selectively enhance what is relevant,” Kraus said. Playing an instrument primes the brain to choose what is relevant in a complex process that may involve reading or remembering a score, timing issues and coordination with other musicians.”

Again, I am most interested to note that in Northwestern’s research shows that children who are musically trained have a better vocabulary and reading ability than children who did not receive music training.

Furthermore Professor Kraus says that “Music training seems to strengthen the same neural processes that often are deficient in individuals with developmental dyslexia or who have difficulty hearing speech in noise.”

Professor Kraus argues for proper investment of resources in music training in schools: “The effect of music training suggests that, akin to physical exercise and its impact on body fitness, music is a resource that tones the brain for auditory fitness and thus requires society to re-examine the role of music in shaping individual development. ”

“Music training for the development of auditory skills,” by Nina Kraus and Bharath Chandrasekaran, will be published July 20 in the journal Nature Reviews Neuroscience.

Weekly Round-Up

 

Eternal Sunshine Of the Spotless Mind

Would you take a pill to erase bad memories?

 

New Year is traditionally a time for many people to make a resolution to give up smoking. The smoking cessation medications bupropion and varenicline may both be associated with changes in the way the brain reacts to smoking cues, making it easier for patients to resist cravings, according to two reports posted online that will appear in the May print issue of Archives of General Psychiatry, one of the JAMA/Archives journals.

If you are a parent of a teen going through puberty you will know all about the hormonal changes they go through.  Now, a Georgia State University scientist has found that those hormones in males may be key to changes in a part of the brain responsible for social behaviors.

It will take some time for those teen brains to develop fully though, as we know now from new research that the brain continues to develop after childhood and puberty, and is not fully developed until people are well into their 30s and 40s. The findings contradict current theories that the brain matures much earlier.

And still on the subject of teenagers, PBS science correspondent, Miles O’Brien looks at what could be happening to teenage brains as they develop in a rapid-fire world of technology and gadgets.

Finally, if you have ever watched the 2004 movie Eternal Sunshine of the Spotless Mind, you will have seen the fictional characters played by Jim Carrey and Kate Winslet use a technique to erase memories of each other when their relationship turns sour. It will have seemed an unreal expectation that we could erase memories so easily, but new research on “erasing” traumatic memories is quickly moving from the realm of science fiction to scientifically backed reality.

Introducing a new feature today – a weekly round-up of the best of the neuroscience news and views and latest research which has caught my attention.

How to use your brain to win friends and influence people

You are probably familiar with the  lyrics of James Taylor’s “You’ve got a friend” and indeed “ain’t it good to know you’ve got a friend when nothing’s going your way.”

But did you know that you have a friend you can call on who is with you all the time?

Say hello to your amydgala – your very own social satnav and your faithful friend.

So what is this amygdala and what role does it play in forming friendships and widening your social network?

Your amydgala 

Deep down in our reptilian brain lies a small thumbnail-sized structure with a name derived from the Greek word for almond. The amygdala has long been linked with a person’s mental and emotional state – in particular an emotional response – often an instant reaction – to something presently happening such as a perceived threat including the behaviours of escape and avoidance.

The bull who would not charge

As far back as the 1950’s a Spanish neuroscientist called Delgado used a tiny radio frequency stimulator implanted into the amygdala – the activation of which produced a variety of effects, including pleasant sensations. Delgado’s most famous experiment occurred at a Cordoba bull breeding ranch where he stepped into the ring with a bull which had a stimulator already implanted in the amygdala. The bull charged Delgado, who then pressed a remote control button which caused the bull to lose its aggressive instinct and to stop its charge. The bull incident was widely mentioned in the popular media at the time.

The amygdala alerts you to danger

In another important study – when brain images were recorded while persons were shown emotionally upsetting films, such as plane crashes or killer whales dismembering and eating baby seals and increase in the activity of the amygdala was observed suggesting that it is involved in storing memories for emotional events. Over the past 10 years neuroscientists have discovered that for it small size the amygdala is very complex with connections to and from many other brain regions and plays a protective role primarily involved in protection, moving us away from potentially dangerous situations.   

You’ve got a friend in your amygdala

In a social situation the amygdala processes reactions to violations concerning personal space. These reactions are absent in persons in whom the amygdala is damaged. Furthermore, the amygdala is found to be activated in when people observe that others are physically close to them, such as when a person being brain scanned knows that an experimenter is standing immediately next to the scanner, versus standing at a distance.

Behold the next big thing in social networking…the amygdala!

In interesting research published recently in the Journal, Nature Neuroscience  it has been shown that the size of your amygdala correlates with the size of your social network – taking the role of the amygdala in social interaction to another level. As a social species a larger amygdala gives us more options to manage our complex social lives – helping us to get along while getting ahead.

Thus jobs involving meeting people such as shopkeepers – who may interact with hundreds people including customers, suppliers and employes in an average day – will develop a larger and more intricately wired amygdala than say someone in solitary confinement.

All this points back to a fundamental finding in neuroscience – your brain is plastic.  So the message is simple – you need to meet as many people as possible if you want a rich and varied social life. You may not get along with everyone but as you learn and persist your amygdala will become your very own on-board social satnav.

 

Exercise doesn’t just make you fitter – it makes you smarter too!

Exercise is important in keeping your heart and lungs healthy. We know for decades that the effort required in exercise allows life-giving oxygen to travel quicker and in greater amounts to all the tissues of the body – allowing the cells in them to grow and divide. A noticeable exception to this rule is the brain.

Neurons are different

Nerve cells or neurons are notoriously bad at dividing. Rather than divide, a neuron survives by making up to 10,000 connections to neighbouring neurons – and this is the key to how we learn and recall as memories are created and strengthened.  This compromise works well for the first four decades of life however by your 50’s a gradual loss of neurons and their connections starts to take it toll resulting in a noticeable reduction in cognition as we find it harder to remember, especially recent events. 

An unexpected finding

Recent scientific findings from Columbia University show that exercise is important in helping to reverse this age-related loss of neurons. In this study in a small group of middle-aged people, exercising just an hour a day, four times a week, for three months triggers the growth of new neurons – a feat which has previously proved almost impossible for neuroscientists to achieve using drugs. Neuroscientists are still working out the possible reasons why simple exercise is so powerful at triggering the birth of neurons but a clue may be that the brain is very well supplied by blood vessels needed to deliver the food and oxygen to help make and maintain the trillions of synapses in the brain. In fact the brain is one of the most oxygen-sensitive organs of the body. It receives 20% of the cardiac output and accounts for about 25% of overall resting oxygen consumption. In addition, the brain as a highly vascular organ is very sensitive to changes in blood perfusion. It seems the extra increase in blood perfusion and life-giving oxygen associated with exercise may invigorate the brain to such a degree that it starts to actually grow new neurons again.

Exercise is as important as drugs

The finding that exercise triggers the brain to grow new nerve cells is a truly stunning discovery that will have implications for public healthcare policies for an increasingly ageing population. In addition, new treatments for brain illness such as Alzheimer’s disease and head injury may involve a combination of different therapies such as medication, psychological therapies, social support, self-help techniques and now, most importantly exercise. This combined approach will treat the person as a whole, and marks the beginning of the journey back to wellness and a normal life.

So the message is simple –if you want to stay smart just get out there and exercise.

Slow protein clearance ‘clue to Alzheimer’s’

Amyloid plaques build up in the brains of people with Alzheimer's disease. Image: BBC Health

The BBC News website this week reports on the latest research to suggest that people with Alzheimer’s disease clear a damaging protein from their brains more slowly than those who are healthy. With an ageing population,  dementia, including Alzheimer’s, is currently seen as one of the main health challenges in Ireland the UK.

Amyloid plaques are one of the hallmarks of Alzheimer’s disease. Amyloid is a general term for protein fragments that the body produces normally. Beta amyloid is a protein fragment snipped from an amyloid precursor protein. In a healthy brain, these protein fragments are broken down and eliminated. For some reason, in Alzheimer’s disease, the fragments accumulate to form hard, insoluble plaques.

The findings from this study suggests that people with Alzheimer’s disease clear the damaging protein from their brains 30% more slowly than those who are healthy suggesting that  it is the poor clearance of the protein, not the build-up, that is the problem. Admittedly it’s a small study – just 24 people were looked at, but exciting, and could help the understanding of the disease.

Not meaning to blow my own trumpet (ahem!) but in 2008 my research group showed how the amyloid protein might be toxic in higher concentration …by inappropriately increasing the concentrations of a neurotransmitter called glutamate in the hippocampus – a brain region long associated with Alzheimer’s disease*. It’s well known that high concentrations of glutamate can damage local nerve cells and thus impair the functioning of the hippocampus.

It’s exciting to see the pieces of evidence coming together as the search for an effective treatment for dementia continues apace.

*  O’Shea S.D., Smith I.M., McCabe O.M., Cronin M.M., Walsh D.M., O’Connor W.T. Sensors. 2008; 8(11):7428-7437.

Latest research from computational neuroscience

Another fascinating topic from the SFN Annual Meeting was the research being undertaken in the area of computational neuroscience.

Computational neuroscience is the study of brain function in terms of the information processing properties of the structures that make up the nervous system.

It is an interdisciplinary science that links the diverse fields of neuroscience, cognitive science and psychology with electrical engineering, computer science, mathematics and physics.

In an interview in the current edition of New Scientist, Professor Terry Sejnowski, head of the computational neurobiology lab at the Salk Institute in La Jolla, California, says some of the most intriguing results in computational neuroscience come from collaborations between modelers and experimentalists.

Professor Sejnowski and his research colleagues’ research in modeling signal transfer patterns throughout the brain has resulted in new techniques which make it possible to simultaneously record signals from many neurons. The sensitivity means scientists can for the first time, watch the output from a neuron spread through the brain.

Research has also found that neurons respond differently to different stimuli (for example, signals required to move a prosthetic arm can change when people are tired). This research will help improve brain-machine interferences such as prosthetic limbs and thought-controlled wheelchairs.

Neuroscience research may help brain injury recovery

New research shows that the way the brain first captures and encodes a situation or event is quite different from how it processes subsequent similar events.

I was interested to read a special report from the Center for Neuro Skills which describes the latest developments into how the brain registers new memory and equally importantly, how it strengthens older memories.

It has been known for years that the so-called NMDA receptor – a  lock on the skin of the nerve cell which is ‘opened’ by a special key – the neurotransmitter glutamate – is involved in new learning and memory.

However this research shows that the way the brain first captures and encodes a situation or event is quite different from how it processes subsequent similar events,  and suggests a whole new NMDA-independent system involving the so-called AMPA receptor – a less powerful type of NMDA receptor –  involved in strengthening older memories.
Why is this so important?   

Well, this new system is known to be critically involved in Alzheimer’s disease and other kinds of brain deficit memory impairment including stroke and head injury.

In fact, you may be interested to know that several drug companies have developed drugs that open the AMPA receptors called ampakines – a class of compounds known to enhance attention span and alertness, and facilitate learning and memory.

Unlike earlier stimulants such as caffeine, methylphenidate (Ritalin), and the amphetamines, ampakines do not seem to have unpleasant, long-lasting side effects such as sleeplessness.

These new memory enhancing drugs will be coming to a pharmacy near you within the next few years!

Don’t forget!