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Weekly Neuroscience Update

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Reductions in cortical surface area and increases in cortical thickness in Down syndrome relative to typical controls. Panel A shows that the cortex surface area is lower in Down syndrome; panel B shows that the cortex is thicker in Down syndrome brains. Small red circles indicate the approximate locations where cortical surface area and thickness were most different between brains of participants with Down syndrome and brains of typically developing participants. Image credit: Lee et al., National Institute of Mental Health

Reductions in cortical surface area and increases in cortical thickness in Down syndrome relative to typical controls. Panel A shows that the cortex surface area is lower in Down syndrome; panel B shows that the cortex is thicker in Down syndrome brains. Small red circles indicate the approximate locations where cortical surface area and thickness were most different between brains of participants with Down syndrome and brains of typically developing participants. Image credit: Lee et al., National Institute of Mental Health

The thickness of the brain’s cerebral cortex could be a key to unlocking answers about intellectual development in youth with Down Syndrome. It could also provide new insights to why individuals with this genetic neurodevelopmental disorder are highly susceptible to early onset Alzheimer’s Disease later in life.

In a study published in The Journal of Experimental Medicine, researchers report a surprising finding that challenges current anatomy and histology textbook knowledge: Lymphatic vessels are found in the central nervous system where they were not known to exist.

Changes in the vaginal microbiome are associated with effects on offspring gut microbiota and on the developing brain, according to a new study published in Endocrinology, a journal of the Endocrine Society.

Researchers discover that a protein called Taranis could hold the key to a good night’s sleep.

A team of researchers has now been able to demonstrate in a study that the bonding hormone oxytocin inhibits the fear center in the brain and allows fear stimuli to subside more easily. This basic research could also usher in a new era in the treatment of anxiety disorders.

Early life stress affects cognitive functioning in low-income children.

Researchers at Monash University have found physical differences in the brains of people who respond emotionally to others’ feelings, compared to those who respond more rationally, in a study published in the journal NeuroImage.

Having a stroke ages a person’s brain function by almost eight years, new research finds — robbing them of memory and thinking speed as measured on cognitive tests. In another pilot study, women who experience more hot flashes, particularly while sleeping, during the menopause transition are more likely to have brain changes reflecting a higher risk for cerebrovascular disease, such as stroke and other brain blood flow problems.

Researchers discover the anatomic reasons for the persistence of musical memory in Alzheimer patients.

A new study on successful ageing has linked better memory performance in older age with patterns of neural compensation. The research sheds light on how memory can remain efficient in spite of common age-related neural decline.

There are more boys than girls diagnosed with autism spectrum disorder (ASD). Now, a study shows that behaviors relevant to autism are more frequently observed in boys than in girls, whether they’re at risk of autism or not. Meanwhile an early intervention program for toddlers with autism spectrum disorder improves their intellectual abilities and reduces autism symptoms – and those results persist years after the children originally received treatment, according to a recent study. And in another study, using functional magnetic resonance imaging, a team of  researchers has shown for the first time that children with autism spectrum disorder who are overly sensitive to sensory stimuli have brains that react differently than those with the disorder who don’t respond so severely to noises, visual stimulation and physical contact.

The stress hormone cortisol strengthens memories of scary experiences. 

Finally, this week, researchers have found that people who speak more than one language have twice as much brain damage as unilingual people before they exhibit symptoms of Alzheimer’s disease. It’s the first physical evidence that bilingualism delays the onset of the disease.

 

Weekly Neuroscience Update

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New brain imaging research from Carnegie Mellon University provides some of the first evidence showing how the brain unconsciously processes decision information in ways that lead to improved decision making. Credit: Carnegie Mellon University

When faced with a difficult decision, it is often suggested to “sleep on it” or take a break from thinking about the decision in order to gain clarity. But new brain imaging research from Carnegie Mellon University, published in the journal “Social Cognitive and Affective Neuroscience,” finds that the brain regions responsible for making decisions continue to be active even when the conscious brain is distracted with a different task. The research provides some of the first evidence showing how the brain unconsciously processes decision information in ways that lead to improved decision-making.

A study from Karolinska Institutet in Sweden has shown that neurons in our brain ‘mirror’ the space near others, just as if this was the space near ourselves. The study, published in the scientific journal Current Biology, sheds new light on a question that has long preoccupied psychologists and neuroscientists regarding the way in which the brain represents other people and the events that happens to those people.

New drugs which may have the potential to stop faulty brain cells dying and slow down the progression of Parkinson’s, have been identified by scientists in a pioneering study which is the first of its kind.

Neuroscientists have discovered that a virtual-reality hand, which is synchronized to “pulse” in time to an individual’s heartbeat, creates the illusion in the brain of “body ownership” – with the brain believing the hand is part of its own body.

Cornell researchers have developed a reliable method to distinguish memory declines associated with healthy aging from the more-serious memory disorders years before obvious symptoms emerge. The method also allows research to accurately predict who is more likely to develop cognitive impairment without expensive tests or invasive procedures.

People who suffer from the common gastrointestinal disorder irritable bowel syndrome (IBS) have more stress-related memory problems than others, according to a new study. The researchers also found that levels of the stress hormone cortisol were related to poor memory performance. While stress has long been known to affect gut symptoms, this is the first study showing that stress also impacts on cognition in IBS.

In a new study using functional magnetic resonance imaging (fMRI), researchers have found that the same brain networks that are activated when you’re burned by hot coffee also light up when you think about a lover who has spurned you.

Sorry I’m late, it’s all down to my chronobiology

Photograph: Getty Images

Individuals differ in terms of their chronotype – that is to say whether you are morning oriented or evening oriented, or somewhere in the middle.

We are well into party season as the holidays approach, with dinners, drinks with friends and similar festive cheer. But in the midst of all the fun there is also an annoyance: the latecomer.

Everyone knows someone who is always late. Maybe you’re one of those people yourself. Theories on why some individuals are late on a regular basis come from a variety of perspectives – anthropological, cultural, neurological and psychological. But are there scientific explanations for chronic lateness?

We are all governed by our circadian clocks. The study of this internal clock comes under the heading of chronobiology. “Circadian rhythms are internal 24-hour rhythms created by the Earth spinning on its axis within a 24-hour period,” says Dr Andrew Coogan, a chronobiologist at NUI Maynooth.

“Life has evolved to take advantage of that. Through evolution we have adapted a time-keeping mechanism. Animals and organisms can anticipate changes in their environment and then react appropriately. It’s important particularly for preyed-upon animals, who know to get home before it’s dark.”

The existence of circadian rhythms was first demonstrated in the 1960s when human subjects were placed into a timeless environment – a concealed former second World War bunker to be exact – with no time-reference points, clocks, natural light and so on.

It was found that the volunteers still expressed 24-hour rhythms through their internal clock. They had energy at appropriate times, slept at night time and were awake during the day.

But circadian rhythms affect individuals differently and can lead to inclinations towards “morningness” or “eveningness” and, in turn, “lateness”.

“Individuals differ in terms of their chronotype – that is to say whether you are morning oriented or evening oriented, or somewhere in the middle,” says Coogan.

“This is both an individual characteristic but also changes across the lifespan so small children generally are morning oriented, teenagers tend towards eveningness, then back towards the morning in adulthood.

“This affects the time of day we are most alert and our cognitive prowess is best set up for. Such individual differences seem to be down in part to genetics, but may also be driven by environmental factors – TVs, computers in bedrooms and street lighting at night might all make for a tendency toward ‘eveningness’.

“It might also explain in part lateness. If you are trying to get out of bed and get to school early yet your body clock is not attuned to that rhythm you may struggle and end up being late. So some of us may be predisposed to be late at different times of the day – probably most pertinent to the morning.”

The inclination towards morningness and eveningness also relates to personality. Eveningness tends to be associated with creativity and impulsiveness.

“Plus if you’re a strongly creative person you lose a sense of time when you’re in the middle of something you find very interesting – otherwise known as the absent-minded professor effect,” says Billy O’Connor, professor of physiology in the Graduate Entry Medical School in the University of Limerick.

“People get so engrossed in what they’re doing, they lose any sense of time. It’s actually a sign of good mental health. But it can be very frustrating for other people.”

Morning people, on the other hand, tend more towards conscientiousness and better organisational skills.

“Some people are future oriented so time is very important to them,” says Coogan. “Those who live in the present are not so bothered with being late.”

Being late for a flight or an important meeting is stressful and some people get addicted to that feeling. “Creating a stressful environment can be used by people to up their game,” says O’Connor. “It helps some people focus but you can become addicted to stress, more specifically the hormone cortisol. Its release gets you whizzing along when you need it most.

“Chronic stress ages the body and the brain. So this kind of behaviour works in the short term and does help some people get more done in their lives. But the brain performs optimally when it is calm and focused.”

There is, of course, one other reason why 3pm means 3.30pm to some people. “It can be a power thing,” says O’Connor. “In a business meeting setting, for example, which is a complex social gathering with multiple agendas and strict rules of engagement. They are not casual affairs so being constantly late for a meeting without a valid reason may be regarded as discourteous in a group.

“It may also be regarded as attention seeking, selfish behaviour and signs of a disorganised mind, and will more than likely result in social exclusion,” he says.

JOHN HOLDEN

This article appeared in the Irish Times 19-12-12

Image Credit: Getty Images