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Smarter kids have big brains as oldsters

In high school I was told that I had a 135 IQ. I immediately spent the next ten years doing things to ruin my brain. I may still have something left.

Your IQ at the age of eleven predicts your brain anatomy sixty years later, according to a Canadian/Scottish team of neuroscientists: Childhood cognitive ability accounts for associations between cognitive ability and brain cortical thickness in old age.

The authors of the new paper, Karama et al, made use of a unique long-term study of Scottish volunteers, all of whom had IQ tests back in 1947, when they were 11. In 2009, aged 73, those who were still alive and willing to participate had an MRI brain scan – a total of 588 people. 

Karama et al show that childhood IQ is correlated with the thickness of the brain’s cerebral cortex in old age. What’s more, IQ at age 70 was correlated with brain anatomy, but no more closely than the age 11 scores were – that is to say, cortical thickness in old age is correlated, not just with IQ in old age, but with IQ at any age.

In other words, people with higher IQs just tend to have a thicker cerebral cortex across the lifespan.

The authors point out, however, that they didn’t include anyone with diagnosed or suspected dementia. It’s certainly true that some forms of dementia cause rapid cortical thinning, and that this is associated with cognitive decline. But dementia aside, it seems that the brain you have at 73 is a reflection of your lifelong IQ. There’s nothing special about old age which drives the relationship.

This result is pretty remarkable, although the correlations were small (coefficients of 0.1 to 0.3, depending upon the region.) Why this correlation exists is another question. One interpretation is that having a thicker cortex makes you more intelligent, and so the correlation between IQ and anatomy would have also been true at age 11.

However it could be that the smarter people took better care of their brains over 60 years, leaving them with more grey matter, even though this wasn’t what made them smart in the first place.

Or maybe not.

 

How to be creative

Turn off your filters.

The brain's prefrontal cortex is thought to be the seat of cognitive control, working as a kind of filter that keeps irrelevant thoughts, perceptions and memories from interfering with a task at hand.

Now, researchers at the University of Pennsylvania have shown that inhibiting this filter can boost performance for tasks in which unfiltered, creative thoughts present an advantage.

The research was conducted by Sharon Thompson-Schill, the Christopher H. Browne Distinguished Professor of Psychology and director of the Center for Cognitive Neuroscience, and Evangelia Chrysikou, a member of her lab who is now an assistant professor at the University of Kansas. They collaborated with Roy Hamilton and H. Branch Coslett of the Department of Neurology at Penn's Perelman School of Medicine and Abhishek Datta and Marom Bikson of the Department of Biomedical Engineering at the City College of New York.

Their work was published in the journal Cognitive Neuroscience.

Previous studies have shown that the prefrontal cortex -- in particular, the left prefrontal cortex -- is one important area of the brain that supports cognitive control. As a test of whether reduced cognitive control might be advantageous in some circumstances, Thompson-Schill's team designed an experiment that involved inhibiting the activity of the left prefrontal cortex in adults while they completed a creative task.

In this task, participants are shown pictures of everyday objects and are asked to quickly come up with uses for them that are out of the ordinary, such as using a baseball bat as a rolling pin. Participants see a sequence of 60 objects, one every nine seconds, and the researchers measure how long it takes for them to come up with a valid response, or if they are unable to do so before the next picture appears.

The researchers hypothesized that high levels of cognitive control would be a detriment to coming up with these kinds of uncommon uses.

"When we use objects in daily life, our cognitive control helps us focus on what the object is typically used for and 'filters out' irrelevant properties," Chrysikou said. "However, to come up with the idea of using a baseball bat as a rolling pin, you have to consider things like its shape and the material it's made of."

"The real takeaway," Thompson-Schill said, "is that when you give people a task for which they do not know the goal -- such as showing them an object and asking, 'What else can you do with this thing' -- anything that they would normally do to filter out irrelevant information about the object will hurt their ability to do the task."

Experiments to test such hypotheses have been aided by new ways of non-invasively manipulating neurons in specific areas of the brain, inducing a variety of temporary changes in perception and performance.

The method Thompson-Schill's team used, called transcranial direct current stimulation, or tDCS, involves passing a weak electrical charge through the brain, aiming the charge's path so it intersects with areas thought to be associated with an ability or behavior. This charge can influence the electrical activity that constitutes cell-to-cell communication in those areas.

"TDCS is believed to induce incremental shifts in the electrical potential of neuronal membranes, making it more or less likely that neurons will reach their threshold for firing," Hamilton said. "In this instance, we employed stimulation in a way that would make it harder for neurons to fire, thereby diminishing behaviorally relevant activity in that part of the brain."

Participants were first split into groups corresponding to three experimental conditions: one would receive tDCS to their left prefrontal cortex for the duration of the task, another would receive it to their right prefrontal cortex and a third would receive what amounted to a placebo. TDCS produces a slight tingling sensation on the scalp when it is first applied, so those in the third group received only a brief period of stimulation before the task began, rather than throughout.

As additional controls, each of these three groups was also split in half, with one set completing the uncommon-use task and the other simply stating what the object is normally used for. And all participants also completed a task that involved remembering strings of numbers, a common exercise in psychological experiments that has been shown not to require the prefrontal cortex.

"We wouldn't want to think that the stimulation affected everything," Thompson-Schill said. "So if we found an effect when participants were remembering numbers, we'd be worried about our interpretation of the data."

As expected, none of the experimental conditions affected participants' performance when asked to recall the sequences of numbers, or when they were asked to say the common uses of the objects they saw. But there was a marked difference between those who received tDCS to their left prefrontal cortex and those who didn't when completing the uncommon-use task.

The right prefrontal cortex and placebo groups couldn't come up with uncommon uses for an average of 15 out of 60 objects, whereas those whose left prefrontal cortices were being inhibited only missed an average of eight.

The latter group was also able to provide correct responses an average of a second faster than the former two.

"A second faster difference is huge in psychology research. We're used to seeing differences measured in milliseconds," Thompson-Schill said. This is probably the biggest effect I've seen over my 20 years in research."

These results lend credence to the idea that high levels of cognitive control may be a disadvantage in some circumstances, such as in early development.

"We differ from non-human primates in having a long period of immaturity in our prefrontal cortex," Thompson-Schill said, "so we started considering whether this might not be an unfortunate accident of nature but rather a feature of our species' developmental path.

The slow development of the prefrontal cortex is one reason children fail at many attention-based tasks but excel at imaginative ones. It may also aid children in rapidly acquiring new knowledge.

"There are things that are important to not filter, in particular when you are learning," Thompson-Schill said. "If you throw out information about your environment as being irrelevant, you miss opportunities to learn about those things."

You can't be both empathetic and logical at the same time

And the scientists can show you.

When the brain fires up the network of neurons that allows us to empathize, it suppresses the network used for analysis, a pivotal study led by a Case Western Reserve University researcher shows.

How could a CEO be so blind to the public relations fiasco his cost-cutting decision has made?

When the analytic network is engaged, our ability to appreciate the human cost of our action is repressed.

At rest, our brains cycle between the social and analytical networks. But when presented with a task, healthy adults engage the appropriate neural pathway, the researchers found.

The study shows for the first time that we have a built-in neural constraint on our ability to be both empathetic and analytic at the same time

The work suggests that established theories about two competing networks within the brain must be revised. More, it provides insights into the operation of a healthy mind versus those of the mentally ill or developmentally disabled.

"This is the cognitive structure we've evolved," said Anthony Jack, an assistant professor of cognitive science at Case Western Reserve and lead author of the new study. "Empathetic and analytic thinking are, at least to some extent, mutually exclusive in the brain."

The research is published in the current online issue ofNeuroImage.

A number of earlier studies showed that two large scale brain networks are in tension in the brain, one which is known as the default mode network and a second known as the task positive network. But other researchers have suggested that different mechanisms drive this tension:

One theory says that we have one network for engaging in goal directed tasks. This theory posits that our second network allows the mind to wander.

The other theory says that one network is for external attention, and the second network is for internal attention.

The new study shows that adults presented with social or analytical problems -- all external stimuli -- consistently engaged the appropriate neural pathway to solve the problem, while repressing the other pathway. The see-sawing brain activity was recorded using functional magnetic resonance imaging.

Jack worked with former Case Western Reserve undergraduates Abigail Dawson, now a graduate student at the University of Otago in Dunedin, New Zealand; Katelyn Begany, now a graduate student at the University of California, Berkeley; and Kevin P. Barry, now a graduate student at Rensselaer Polytechnic Institute. Other co-authors are, from Case Western Reserve: former research assistant, Regina L. Leckie and Angela H. Ciccia, an assistant professor of psychological sciences; and Abraham Z. Snyder, MD, a professor of radiology at Washington University in St. Louis.

Jack said that a philosophical question inspired the study design: "The most persistent question in the philosophy of mind is the problem of consciousness. Why can we describe the workings of a brain, but that doesn't tell us what it's like to be that person?"

"The disconnect between experiential understanding and scientific understanding is known as the explanatory gap," Jack said. "In 2006, the philosopher Philip Robbins and I got together and we came up with a pretty crazy, bold hypothesis: that the explanatory gap is driven by our neural structure. I was genuinely surprised to see how powerfully these findings fit that theory." Philip Robbins is an associate professor of philosophy at the University of Missouri.

These findings suggest the same neural phenomenon drives the explanatory gap as occurs when we look at a visual illusion such as the duck-rabbit, he continued. The drawing of the head of the animal can be seen as a duck facing one direction or a rabbit facing the other, but you can't see both at once.

"That is called perceptual rivalry, and it occurs because of neural inhibition between the two representations," Jack said. "What we see in this study is similar, but much more wide-scale. We see neural inhibition between the entire brain network we use to socially, emotionally and morally engage with others, and the entire network we use for scientific, mathematical and logical reasoning.

"This shows scientific accounts really do leave something out -- the human touch. A major challenge for the science of the mind is how we can better translate between the cold and distant mechanical descriptions that neuroscience produces, and the emotionally engaged intuitive understanding which allows us to relate to one another as people."

The researchers recruited 45 healthy college students, and asked each to take five 10-minute turns inside a magnetic resonance imager. Meanwhile, the researchers randomly presented them with 20 written and 20 video problems that required them to think about how others might feel and with 20 written and 20 video problems that required physics to solve.

After reading the text or viewing the video, the students had to provide an answer to a yes-no question within seven seconds. Each student's session in the MRI included twenty 27-second rest periods, as well as variable delays between trials lasting 1, 3 or 5 seconds. Students were told to look at a red cross on the screen in front of them and relax during the rests.

The MRI images showed that social problems deactivated brain regions associated with analysis, and activated the social network. This finding held true whether the questions came via video or print. Meanwhile, the physics questions deactivated the brain regions associated with empathizing and activated the analytical network.

"When subjects are lying in a scanner with nothing to do, which we call the resting state, they naturally cycle between the two networks," Jack said. "This tells us that it's the structure of the adult brain that is driving this, that it's a physiological constraint on cognition."

The finding has bearings on a variety of neuropsychiatric disorders, from anxiety, depression and ADHD to schizophrenia -- all of which are characterized by social dysfunction of some sort, Jack said. "Treatment needs to target a balance between these two networks. At present most rehabilitation, and more broadly most educational efforts of any sort, focus on tuning up the analytic network. Yet, we found more cortex dedicated to the social network."

Perhaps most clearly, the theory makes sense in regards to developmental disabilities such as autism and Williams syndrome. Autism is often characterized by a strong ability to solve visuospatial problems, such as mentally manipulating two and three-dimensional figures, but poor social skills. People with Williams syndrome are very warm and friendly, but perform poorly on visuospatial tests.

But, even healthy adults can rely too much on one network, Jack said. A look at newspaper business pages offers some examples.

"You want the CEO of a company to be highly analytical in order to run a company efficiently, otherwise it will go out of business," he said. "But, you can lose your moral compass if you get stuck in an analytic way of thinking."

"You'll never get by without both networks," Jack continued. "You don't want to favor one, but cycle efficiently between them, and employ the right network at the right time."

The researchers continue to test the theory, studying whether brains will shift from the social network to the analytical when students in the MRI see people depicted in a dehumanizing way, that is, as animals or objects. The group is also studying whether disgust and social stereotyping confound our moral compass by recruiting the analytical network and depressing social network activity.