Thursday, October 18, 2012

The brain map that shows the differences in the brains of autistic people can explain their difficulties - and also shed light on their unique talents

I am pleased to see noted below something I have long drawn attention to:  That autistic people tend to have larger heads and hence presumably larger underlying brains.  And the fact that the enlargement is not uniform across brain areas  -- and hence may be random -- explains why each autistic person has a different pattern of abilities

Scientists investigating the brain of one of the world's most famous autistic people have found several features that can explain her unique talents.

Temple Grandin, professor of animal sciences at Colorado State University, is what is known as a 'savant' - someone who shows some of the social deficits of autism yet also has some exceptional abilities.

A tireless campaigner for autism research and awareness she is known for her exceptional non-verbal intelligence, spatial reasoning, sharp visual acuity and an uncanny gift for spelling and reading.

The subject of an award-winning eponymous-titled biographical film starring Claire Danes, Professor Grandin was also in 2010 listed in the Time 100 list of the 100 most influential people in the world in the 'Heroes' category.

In a bid to understand her cognitive gifts, and the accompanying weaknesses, a group of neuroscientists gave the professor a series of psychological tests and scanned her brain using several imaging processes.

Jason Cooperrider, a graduate student at the University of Utah who presented the work at the Society for Neuroscience's annual meeting, explained their aims to the Simons Foundation Autism Research Initiative.

'We asked how might brain structure and function be related to both outstanding ability and outstanding disability — the autism — within the same brain,' he said.

The professor received exceptionally high scores on several psychological assessments, including tests of reading, spelling and spatial reasoning.

She achieved a phenomenal perfect score on Raven's Coloured Progressive Matrices test, which assesses non-verbal reasoning. Her weakest skill was found to be verbal working memory.

Scans showed Professor Grandin's brain is significantly larger than that of three matched neurotypical control subjects - something seen in some children with autism but which scientists do not yet understand.

Her lateral ventricles - chambers which hold cerebrospinal fluid - are different in size, with the left much much larger than the right, a finding Mr Cooperrider described as 'quite striking'.

On both sides, the professor possesses unusually large amygdala, sectors of the brain which are part of the limbic system and have been shown to perform a primary role in the processing of memory and emotional reactions.

The researchers also traced white-matter connections in Professor Grandin's brain using diffusion tensor imaging, finding what they dubbed 'enhanced' connections in the left precuneus, a region involved with episodic memory, visuospatial processing, reflections upon self, and aspects of consciousness.

They found she also has enhanced white matter in the left inferior fronto-occipital fasciculus. This region connects the frontal and occipital lobes, which might explain the professor's keen visual acuity, the researchers said.

In keeping with the double-edged nature of Professor Grandin's condition, she also has some weak connections, which the researchers said were defined in part by decreased integrity of brain-tissue fibres.

One weak area was her left inferior frontal gyrus, which includes the famous Broca's area, which has functions linked to speech production and impairment of which can leave brain injury sufferers mute. Professor Grandin's right fusiform gyrus - a brain region involved in facial and body recognition - also had compromised connections.

The findings agreed with the professor's own personal assessments of her abilities. She has previously written how words are, for her, only understood when translated into pictures and described how she finds socialising 'boring'.

She has noted in her autobiographical works that autism affects every aspect of her life.

She has to wear comfortable clothes to counteract her sensory integration dysfunction and has structured her lifestyle to avoid sensory overload.


Skipping breakfast to lose weight makes you fatter - and far more likely to raid the vending machine

More evidence that dieting makes you fat

If you think skipping your morning tea and toast will help you shed a few pounds, you could be mistaken.  Researchers claim people who miss breakfast not only eat more for lunch but also crave fatty and sugary foods, putting them at risk of gaining rather than losing weight.

Scientists at Imperial College London scanned the brains of 21 volunteers while they looked at pictures of different foods, such as salads and chocolate.

The volunteers also rated how appealing they found the foods, which ranged from salads and vegetables to calorie-laden chocolates, desserts, cakes, pizzas and burgers.

This was done twice - once after the men and women had eaten breakfast and again on a morning when they hadn’t eaten since the night before.

Afterwards, they were given a pasta lunch and told they could eat as much as they liked.

Those who had missed breakfast ate about 250 calories more - the equivalent of five Jaffa Cakes or a chunky Kit Kat.

They also found the high-calorie foods more tempting, with the chocolate the most appealing food of all, the Society for Neuroscience’s annual conference in New Orleans heard.

This suggests that if they had had a choice of foods for lunch, they would have homed in on the unhealthy ones and so packed away even more calories, said researcher Tony Goldstone.

The MRI scans showed a region called the orbital frontal cortex, which tells the brain how important or tasty a food is, to light up more when breakfast had been skipped.  Thoughts of high-calorie foods made it particularly active.

It is thought that when we skip meals, our gut releases hormones that act on the orbital frontal cortex, priming it to steer our thoughts towards sugary and fatty treats.

While this might make sense in times of famine, when it is essential to get as many calories as possible, when food is plentiful, it could lead to us eating more than is good for us.

Dr Goldstone said: ‘Through the participants’ MRI results and observations of how much they ate at lunch, we found ample evidence that fasting made people hungrier and increased the appeal of high-calorie foods and the amount people ate.

‘Beware of going for long periods without eating because you are going to crave high-calorie foods much more because of changes in how your orbital frontal cortex works.


No comments: