Dyslexia, Autism and the Cerebellum: Frontal Lobes not the home of Intelligence

Given that Dyslexia and Autism are disorders of the Cerebellum, human intelligence cannot be explained by the size of the brain's frontal lobes, say researchers. 

Research into the comparative size of the frontal lobes in humans and other species has determined that they are not -- as previously thought -- disproportionately enlarged relative to other areas of the brain, according to the most accurate and conclusive study of this area of the brain.

It concludes that the size of our frontal lobes cannot solely account for humans' superior cognitive abilities.

The study by Durham and Reading universities suggests that supposedly more 'primitive' areas, such as the cerebellum, were equally important in the expansion of the human brain.

These areas may therefore play unexpectedly important roles in human cognition and its disorders, such as autism and dyslexia, say the researchers.

The study is published in the Proceedings of the National Academy of Sciences (PNAS) today.

The frontal lobes are an area in the brain of mammals located at the front of each cerebral hemisphere, and are thought to be critical for advanced intelligence.

Lead author Professor Robert Barton from the Department of Anthropology at Durham University, said: "Probably the most widespread assumption about how the human brain evolved is that size increase was concentrated in the frontal lobes."

"It has been thought that frontal lobe expansion was particularly crucial to the development of modern human behaviour, thought and language, and that it is our bulging frontal lobes that truly make us human. "

"We show that this is untrue: human frontal lobes are exactly the size expected for a non-human brain scaled up to human size."

"This means that areas traditionally considered to be more primitive were just as important during our evolution. "

"These other areas should now get more attention. In fact there is already some evidence that damage to the cerebellum, for example, is a factor in disorders such as autism and dyslexia."

The scientists argue that many of our high-level abilities are carried out by more extensive brain networks linking many different areas of the brain.

They suggest it may be the structure of these extended networks more than the size of any isolated brain region that is critical for cognitive functioning.

Previously, various studies have been conducted to try and establish whether humans' frontal lobes are disproportionately enlarged compared to their size in other primates such as apes and monkeys.

They have resulted in a confused picture with use of different methods and measurements leading to inconsistent findings.

Journal Reference:

1. Robert A. Barton and Chris Venditti. Human frontal lobes are not relatively large. PNAS, May 13, 2013 DOI:10.1073/pnas.1215723110

Brain Structure of Infants predicts Language Skills at one year

Using a brain-imaging technique that examines the entire infant brain, researchers have found that the anatomy of certain brain areas – the hippocampus and cerebellum – can predict children's language abilities at 1 year of age. 

The University of Washington study is the first to associate these brain structures with future language skills. 

The results are published in the January issue of the journal Brain and Language.

"The brain of the baby holds an infinite number of secrets just waiting to be uncovered, and these discoveries will show us why infants learn languages like sponges, far surpassing our skills as adults," said co-author Patricia Kuhl, co-director of the UW's Institute for Learning & Brain Sciences.

Children's language skills soar after they reach their first birthdays, but little is known about how infants' early brain development seeds that path.

Identifying which brain areas are related to early language learning could provide a first glimpse of development going awry, allowing for treatments to begin earlier.

"Infancy may be the most important phase of postnatal brain development in humans," said Dilara Deniz Can, lead author and a UW postdoctoral researcher.

"Our results showing brain structures linked to later language ability in typically developing infants is a first step toward examining links to brain and behavior in young children with linguistic, psychological and social delays."

In the study, the researchers used magnetic resonance imaging to measure the brain structure of a mix of 19 boys and girls at 7 months of age.

The researchers used a measurement called voxel-based morphometry to determine the concentration of gray matter, consisting of nerve cells, and of white matter, which make up the network of connections throughout the brain.

The study is the first to relate the outcomes of this whole-brain imaging technique to predict future ability in infants.

The whole-brain approach freed the researchers from having to select a few brain regions for study ahead of time, ones scientists might have expected to be involved based on adult data.

Read the full article at: Medical Express

Scientists Find Brain Abnormalities Among Children with Wolfram syndrome

Early childhood brain abnormalities among Wolfram syndrome patients have been noticed by scientists from the Washington University School of Medicine in St Louis.

Wolfram syndrome is very rare condition affecting one in 770,000 children.

It causes diabetes, hearing problem, vision loss and kidney problems in childhood.

As the child grows older it starts developing cognitive disorders and dementia and more than half die before their 30th birthday.

Earlier, scientists had identified brain abnormalities but they had assumed these changes could not be detected in early childhood. The new findings suggest that some changes in the brain area occur in early childhood.

"This work strongly suggests that brain changes occur very early in the disease," said Tamara Hershey, researcher at the Washington University School of Medicine, in a statement.

"The Wolfram gene is important throughout the body - in the heart, retina, pancreas and so on. The pancreas is affected very early in development eventually leading to diabetes, so it stands to reason that other organs like the brain may also be affected at an early age, even before a child experiences any cognitive problems."

Scientists made the finding while studying brain scans of Wolfram patients. During the study, they took brain scans of Wolfram patients aged between 5 to 25 and other young patients who only had type 1 diabetes.

When then they compared the brain scans of young children with the Wolfram patients' brain scans, they detected mild brain abnormalities among the young diabetes patients.

"These individuals are intact cognitively, and some of them are very smart, high-functioning kids but we have been able to detect significant differences in the size of certain brain structures, leading us to believe that some of these differences must happen during brain development," Hershey said.

Scientists had identified changes in the brainstem and the cerebellum. They also found that the skulls of these children tended to be smaller than what would have been expected, based on their ages at the time of the study.

The researchers also detected differences in the thickness of the brain's cortex, particularly in parts of the cortex related to vision.

"We were able to pinpoint those regions of the brain that are most affected in terms of size - the brainstem and the cerebellum and we also used a type of imaging called diffusion tensor imaging that allowed us to measure the integrity of white matter pathways in the brain.

Again, we found evidence that the brainstem and the cerebellum white matter were affected in patients with Wolfram syndrome, compared to those with type 1 diabetes only and healthy controls," Hershey said.

Scientists claim that by conducting more MRI scans and continuing to track patients with Wolfram syndrome over time, they might be able to distinguish changes that occur during brain development from those that occur due to degeneration related to the disorder.