Reduced brain volume in kids with low birth-weight tied to academic struggles

An analysis of recent data from magnetic resonance imaging (MRI) of 97 adolescents who were part of study begun with very low birth weight babies born in 1982-1986 in a Cleveland neonatal intensive care unit has tied smaller brain volumes to poor academic achievement.

More than half of the babies that weighed less than 1.66 pounds and more than 30 percent of those less than 3.31 pounds at birth later had academic deficits. (Less than 1.66 pounds is considered extremely low birth weight; less than 3.31 pounds is labeled very low birth weight.) Lower birth weight was associated to smaller brain volumes in some of these children, and smaller brain volume, in turn, was tied to academic deficits.

Researchers also found that 65.6 percent of very low birth weight and 41.2 percent of extremely preterm children had experienced academic achievement similar to normal weight peers.

The research team — led by Caron A.C. Clark, a scientist in the Department of Psychology and Child and Family Center at the University of Oregon — detected an overall reduced volume of mid-brain structures, the caudate and corpus callosum, which are involved in connectivity, executive attention and motor control.

The findings, based a logistic regression analyses of the MRIs done approximately five years ago, were published in the May issue of the journal Neuropsychology. The longitudinal study originally was launched in the 1980s with a grant from the National Institute of Child Health and Human Development (National Institutes of Health, grant HD 26554) to H. Gerry Taylor of Case Western University, who was the senior author and principal investigator on the new paper.

"Our new study shows that pre-term births do not necessarily mean academic difficulties are ahead," Clark said. "We had this group of children that did have academic difficulties, but there were a lot of kids in this data set who didn’t and, in fact, displayed the same trajectories as their normal birth-weight peers."

Academic progress of the 201 original participants had been assessed early in their school years, again four years later and then annually until they were almost 17 years old. “We had the opportunity to explore this very rich data set,” Clark said. “There are very few studies that follow this population of children over time, where their trajectories of growth at school are tracked. We were interested in seeing how development unfolds over time.”

The findings, Clark added, provide new insights but also raise questions such as why some low-birth-weight babies develop normally and others do not? “It is very difficult to pick up which kids will need the most intensive interventions really early, which we know can be really important.”

The findings also provide a snapshot of children of very low birth weights who were born in NICU 30 years ago. Since then, technologies and care have improved, she said, meaning that underweight babies born prematurely today might have an advantage over those followed in the study. However, she added, improving NICUs also are allowing yet smaller babies to survive.

Clark now is exploring these findings for early warning clues that might help drive informed interventions. “Pre-term birth does mean that you are much more likely to experience brain abnormalities that seem to put you at risk for these outcomes,” she said. “They seem to be a pretty strong predictor of poor cognitive development as children age. We really need to find ways to prevent these brain abnormalities and subsequent academic difficulties in these kids who are born so small.”

Too early to learn

Reseachers from Bochum and Warwick suggest consequences for planning school lessons

Large numbers of preterm born babies will place new demands on education system

About 15 million, i.e., more than ten per cent of all babies worldwide are born preterm every year; that is before the 37th week of pregnancy – and the numbers are rising due to improvements in neonatal medicine and demographic changes. Recent studies suggest that delivery at any gestation other than full term (39 to 41 weeks gestational age) may impair brain development, rendering survivors at risk for adverse neuro-cognitive outcomes. Considering that 50 per cent of children are born before the 39th week of pregnancy, even small increases in cognitive impairments may have large effects on a population level. “As the total number of children born preterm increases there will be parallel increases in special education needs placing new demands on the education system,” Julia Jäkel and her colleagues say. To date, uncertainties remain regarding the nature and underlying causes of learning difficulties in preterm children. The new cognitive workload model now reconciles previous inconsistent findings on the relationship of gestational age and cognitive performance.

Cognitive deficits of children born preterm depend on the workload of the task

The research team tested 1326 children, born between weeks 23 and 41 of pregnancy, at an age of eight years. Data were collected as part of the prospective Bavarian Longitudinal Study. The children took part in a range of cognitive tests with varying workload. High workload tasks require the simultaneous integration of different sources of information, thereby placing high demands on the so called working memory. The results: The higher the workload and the shorter the pregnancy duration, the larger were the cognitive performance deficits. Deficits were disproportionally higher for children born before the 34th week of pregnancy compared with children born after week 33. Being born preterm specifically affected the ability to solve high workload tasks, whereas lower workload tasks were largely unaffected.

Results are relevant for cognitive follow-ups and planning of school lessons

According to the researchers, these results should be taken into account for routine cognitive follow-ups of preterm children as well as for planning school lessons. “New studies suggest that computerized training can improve working memory capacity,” Prof Dieter Wolke from Warwick says. “In addition, educational interventions could be developed in which information is not presented simultaneously to preterm children but more slowly and sequentially to promote academic attainment.”

Bilingual children have a better “working memory” than monolingual children

A study conducted at the University of Granada and the University of York in Toronto, Canada, has revealed that bilingual children develop a better working memory –which holds, processes and updates information over short periods of time– than monolingual children. The working memory plays a major role in the execution of a wide range of activities, such as mental calculation (since we have to remember numbers and operate with them) or reading comprehension (given that it requires associating the successive concepts in a text).

The objective of this study –which was published in the last issue of the Journal of Experimental Child Psychology– was examining how multilingualism influences the development of the “working memory” and investigating the association between the working memory and the cognitive superiority of bilingual people found in previous studies.

Executive Functions

The working memory includes the structures and processes associated with the storage and processing of information over short periods of time. It is one of the components of the so-called “executive functions”: a set of mechanisms involved in the planning and self-regulation of human behavior. Although the working memory is developed in the first years of life, it can be trained and improved with experience.

According to the principal investigator of this study, Julia Morales Castillo, of the Department of Experimental Psychology of the University of Granada, this study contributes to better understand cognitive development in bilingual and monolingual children. “Other studies have demonstrated that bilingual children are better at planning and cognitive control (i.e. tasks involving ignoring irrelevant information or requiring a dominant response). But, to date, there was no evidence on the influence of bilingualism on the working memory.

The study sample included bilingual children between 5 and 7 years of age (a critical period in the development of the working memory). The researchers found that bilingual children performed better than monolingual children in working memory tasks. Indeed, the more complex the tasks the better their performance. “The results of this study suggest that bilingualism does not only improve the working memory in an isolated way, but they affect the global development of executive functions, especially when they have to interact with each other”, Morales Castillo states.

Music Education

According to the researcher, the results of this study “contribute to the growing number of studies on the role of experience in cognitive development”. Other studies have demonstrated that children performing activities such as music education have better cognitive capacities. “However, we cannot determine to what extent children perform these activities due to other factors such as talent or personal interest”.

“However, the children in our study were bilingual because of family reasons rather than because of an interest in languages.

Monkey See, Monkey Do: Visual Feedback Is Necessary for Imitating Facial Expressions

Studies of the chameleon effect confirm what salespeople, tricksters, and Lotharios have long known: Imitating another person’s postures and expressions is an important social lubricant.

But how do we learn to imitate with any accuracy when we can’t see our own facial expressions and we can’t feel the facial expressions of others?

Richard Cook of City University London, Alan Johnston of University College London, and Cecilia Heyes of the University of Oxford investigate possible mechanisms underlying our ability to imitate in two studies published in Psychological Science, a journal of the Association for Psychological Science.

In the first experiment, the researchers videotaped participants as they recited jokes and then asked them to imitate four randomly selected facial expressions from their videos. When they achieved what they perceived to be the target expression, the participants recorded the attempt with the click of a computer mouse.

A computer program evaluated the accuracy of participants’ imitation attempts against a map of the target expression. In contrast to previous studies that relied on subjective assessments, this new technology allowed for automated and objective measurement of imitative accuracy.

In one experiment, the researchers found that participants who were able to see their imitation attempts through visual feedback improved over successive attempts. But participants who had to rely solely on proprioception – sensing the relative position of their facial features – got progressively worse.

These results are consistent with the associative sequence-learning model, which holds that our ability to imitate accurately depends on learned associations between what we see (in the mirror or through feedback from others) and what we feel.

Cook and colleagues conclude that contingent visual feedback may be a useful component of rehabilitation and skill-training programs that are designed to improve individuals’ ability to imitate facial gestures.

Want Your Baby to Learn? Research Shows Sitting Up Helps

From the Mozart effect to educational videos, many parents want to aid their infants in learning. New research out of North Dakota State University, Fargo, and Texas A&M shows that something as simple as the body position of babies while they learn plays a critical role in their cognitive development.

The study shows that for babies, sitting up, either by themselves or with assistance, plays a significant role in how infants learn. The research titled “Posture Support Improves Object Individuation in Infants,” co-authored by Rebecca J. Woods, assistant professor of human development and family science and doctoral psychology lecturer at North Dakota State University, and by psychology professor Teresa Wilcox of Texas A&M, is published in the journal Developmental Psychology®.

The study’s results show that babies’ ability to sit up unsupported has a profound effect on their ability to learn about objects. The research also shows that when babies who cannot sit up alone are given posture support from infant seats that help them sit up, they learn as well as babies who can already sit alone.

“An important part of human cognitive development is the ability to understand whether an object in view is the same or different from an object seen earlier,” said Dr. Woods. Through two experiments, she confirmed that 5-and-a-half- and 6-and-a-half-month-olds don’t use patterns to differentiate objects on their own. However, 6-and-a-half-month-olds can be primed to use patterns, if they have the opportunity to look at, touch and mouth the objects before being tested.

“An advantage the 6-and-a-half-month-olds may have is the ability to sit unsupported, which makes it easier for babies to reach for, grasp and manipulate objects. If babies don’t have to focus on balancing, their attention can be on exploring the object,” said Woods.

In a third experiment, 5-and-a-half-month-olds were given full postural support while they explored objects. When they had posture support, they were able to use patterns to differentiate objects. The research study also suggests that delayed sitting may cause babies to miss learning experiences that affect other areas of development.

“Helping a baby sit up in a secure, well-supported manner during learning sessions may help them in a wide variety of learning situations, not just during object-feature learning,” Woods said. “This knowledge can be advantageous, particularly to infants who have cognitive delays who truly need an optimal learning environment.”

Iron deficiency and cognitive development: New insights from piglets

University of Illinois researchers have developed a model that uses neonatal piglets for studying infant brain development and its effect on learning and memory. To determine if the model is nutrient-sensitive, they have done some research on the effects of iron-deficient diets.

“Iron deficiency is a major problem worldwide,” said Rodney Johnson, professor of animal sciences and director of the Division of Nutritional Sciences. “Infants who experience iron deficiency during the first 6 to 12 months of age can have irreversible developmental delays in cognition.”

He said that, even in the United States, iron deficiency is a significant problem. “Babies born to obese mothers are at risk for iron deficiency,” said Johnson. “Furthermore, the incidence of child obesity is increasing, and being overweight or obese is a risk factor for iron deficiency. Overweight toddlers are nearly three times more likely to suffer from iron deficiency than are those with a healthy weight.”

Johnson said that this work highlights a new translational model for studying micronutrient deficiencies. Traditional rodent models are less suited for examining these kinds of questions because they cannot be weaned early and placed on experimental diets. Pigs, however, are a precocial species, which means that their motor and sensory skills are quite well developed at birth. This facilitates early weaning and behavioral testing.

An article describing this research, “Early Life Iron Deficiency Impairs Spatial Cognition in Neonatal Piglets” by Jennifer L. Rytych, Monica R. P. Elmore, Michael D. Burton, Matthew S. Conrad, Sharon M. Donovan, Ryan N. Dilger, and Rodney W. Johnson has recently been published in The Journal of Nutrition.

Piglets substitute for human babies in cognitive science maze test

A team from the Beckman Institute at the University of Illinois is using piglets instead of human babies to try and model the cognitive development of infants.

Human infants cannot be used as laboratory subjects. The idea to use piglets came when one of neuroscientist Rodney Johnson’s former students, who was working for an infant formula company, asked him about finding ways to monitor the differences in cognitive development between breast-fed and formula-fed children.

As a result he and his colleague Ryan Dilger became interested in using the neonatal piglet as a model for human brain development. The growth and development of the piglet brain is similar to that of the human brain — at birth the human brain is 25 percent of adult size. In the first two years of life, it reaches 85 to 90 percent of adult size. The piglet brain grows in a similar way in a shorter time.

They wanted to see whether they could develop tests to look at learning and memory development using these pigs. First of all they developed MRI techniques to quantify the size of the brain, taking measurements at regular intervals.

They then developed a test using a maze to assess piglets’ learning and memory. This turned out to be much more complicated than expected. Johnson said: “When we first started these studies, we used things like Skittles and apple slices as a reward because that’s what people using older pigs had done.”

However, the piglets were used to being fed on infant formula and so had no interest in solid food, nor were they motivated to perform tasks if the reward was the same as their regular food. The solution was to use Nesquik chocolate milk as a reward.

Tests took place in a plus-sign-shaped maze with one arm blocked off to leave a T shape. Piglets were trained to locate the milk reward using visual cues from outside the maze. When they learned how to do this and the reward location was moved, and the pigs were retested to assess learning and working memory.

Having established that the tests can be used to measure cognitive abilities, the team will examine how nutrient deficiencies (such as iron) and infections (such as pneumonia) affect the human brain during this time of early brain growth.

Johnson said: “There is a lot of interest in the concept of programming, the notion that things that occur early in life set that individual up for problems that occur many years later. Because the pig brain grows so much like a human brain, we thought this could be a very attractive model.”

In order to measure changes in the brain they look at neuroinflammation, neuron growth and changes, as well as biochemical in the brain.

The team hopes to receive funding to look at maternal viral infections, where pregnant pigs will be infected with diseases to see how it affects the brain development of their offspring.