14 March 2011

My Brain Hurts

In the middle of a workshop last week, one of my participants announced that she needed a rest as her brain was full! I was aware that I had possibly overloaded the class with information, but was intrigued by her comment that her brain hurt and she all of a sudden felt utterly exhausted.

We are all familiar with the mid afternoon energy slumps and the consistently well documented advice around regulating blood sugar levels by eating little and often, with a good balance of nutrients, keeping hydrated, maintaining a regular sleep pattern to promote healthy rhythms etc etc. But what happens when we feel real brain “pain” and are utterly depleted?

Fatigue, like pain is fundamentally a brain mediated sensation. As with pain, most people report that they experience fatigue as an overwhelming phenomenon, apparently occurring mainly in the muscular skeletal areas. However on closer questioning, people also refer to mental fatigue and this is typically precipitated by complex neurological tasks or intense bouts of concentration. At the extreme end, some people may suffer from Chronic Fatigue Syndrome, which is still a subject of intense interest to neuroscientists – as it is as much about the brain, the nervous system as it is about the physical body.

Fortunately my participant came back from the mid-afternoon workshop break after a glass of water and a walk around the block, challenging the group for more information!  It's as though when we get to overload and we need a period of down-time to process the information and clear the 'log-jam' before coming back for more.

11 March 2011

Older drivers 'see too much'

In October 2009 we reported on research by Adam Gazzaley of the University of California in an item entitled “Does your brain slow down as you get older?” The researchers, who were looking into the speed at which older people perform mental tasks relative to their younger counterparts, found that the brains of older people were not slower but that they appear slower because older people’s brains are not as good at blocking irrelevant information. They therefore are more easily distracted and find it harder to concentrate on the task in hand.

I mention this as recent research by Professor Duje Tadin at the University of Rochester in New York has produced similar conclusions.

His research was investigating a worrying phenomenon of ageing that results in older drivers failing to notice other cars, pedestrians and cyclists moving around them. For some time this has been blamed on a reduced ability to notice moving objects, but the research suggests that it is actually caused by an inability to separate the objects from the background.

In healthy young brain a region called the middle temporal visual area actively suppresses irrelevant background motion so that the person can concentrate on the more important movements of smaller objects in the foreground. Previous studies have found that elderly people, as well as those with psychological conditions such as schizophrenia and depression are better at perceiving motion in the background.

The problem is that since our brains are only capable of consciously processing a limited amount of information at any one time, this heightened awareness of the background serves as a distraction that draws our attention away from the more important foreground objects.

"The amount of visual information around us is huge, and we don't have the brain power to process it all," Tadin said. "Evolutionarily speaking, moving objects are the most important visual features to detect quickly, because they could be your lunch or they could want to eat you for lunch. It just makes sense that our vision prioritizes processing them."

The results of both studies would therefore suggest that a natural part of the ageing process is an improvement in our ability to perceive things holistically, but decrease in our ability to concentrate on the specifics of any one thing.

While the implications of this research for the medical professions lie in improved diagnosis of certain medical conditions, the implication for employers is that to get the best from their staff they should consider these age-related differences when assigning tasks.

Risk and Reward

When a child is first born it is broadly speaking true to say that they know nothing.  While they enjoy the support and protection of their parents this is not a problem, but if they are to survive in the longer term, they need to learn fast, which is why we are all born with an innate sense of curiosity.

At this stage of life learning consists of experimenting, pushing boundaries, copying others and, above all, making mistakes.  Adults also play an important role in our learning by helping us differentiate between good behaviour and practices and bad ones.  For example, we quickly learn to recognise the meaning of the different sounds our mothers make when we on the one hand do something cute, or on the other use her favourite lipstick to draw on the wall.

As we grow bigger and more physically capable, this learning-by-doing approach brings increased risks, which is why parents will often keep toddlers on reins to stop them suddenly running into the road. 

At some stage though we need to be able to fend for ourselves, so we have to develop the ability to assess and judge a situation before acting.  This cognitive process takes place in the cerebral brain, which is the part of the brain that allows humans to over-ride our more basic animal instincts – to think before we act. Recent research at the University of Oregon has highlighted the ways in which the regions of the brain involved in making these reasoned judgements develop.  Their research study used fMRI (functional magnetic resonance imaging) scans of the brains of 24 girls and 12 boys when they were 10 years old and then again three years later when they were 13.

Their findings, which are detailed in the March 2011 edition of the journal Neuron, were that activity in an area of the prefrontal cortex increased significantly between the ages of 10 and 13.  So at just the time when parents are worrying that their children are coming under the influence of other people and being exposed to a broader range of risks, their brains are adapting to help them cope.

However, this raises the question as to why this region of the brain does not develop earlier, as I am sure that most parents would agree that even at 13 years children tend to take many more risks than they would like.  The most likely answer is that the inhibitions of youth are a key component in a child’s learning and that if they were restricted by a greater sense of risk aversion their learning would be impeded.  It is also likely that by developing this ability later in life and slowly over a period of time enables children to learn the skill of balancing risk and reward.

Possibly these research findings explain why some children switch from taking too many risks in their early childhood to being far too risk averse as teenagers.
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