such as "Introduction", "Conclusion"..etc
March 26, 2009 — A collaborative study led by
researchers at the Montreal Neurological Institute (MNI), McGill
University has demonstrated a positive link between cognitive ability
and cortical thickness in the brains of healthy 6 to 18 year olds. The
correlation is evident in regions that integrate information from
different parts of the brain.
The imaging study published this week in a special issue of scientific journal Intelligence is the largest and most comprehensive of its kind with a representative sample of healthy children and adolescents.
This study stems from the NIH MRI Study of Normal Brain Development,
for which the MNI was the data coordinating centre. The database
contains MRI scans and other data on the structure and function of the
developing brains. More than 500 children and adolescents from newborns
to 18-year-olds had brain scans multiple times over a period of years
as well as intelligence, neuropsychological, verbal, non-verbal and
behavioural tests. This information is now contained within the
database allowing scientists to study how normal developmental changes
in brain anatomy relate to motor and behavioural skills, such as motor
coordination and language acquisition. Even higher-order skills like
planning, IQ, and organizational skills can be assessed.
Previous studies have shown that intelligence and cognitive ability
are correlated with regional brain structure and function. The
association between regional cortical thickness and intelligence has
been little studied and most previous studies of normal children had a
relatively small sample. So with improvements in MRI-based
quantification of cortical thickness and a much larger sample,
researchers aimed to examine this relationship and to further
characterize and identify brain areas where cortical thickness was
associated with cognitive performance.
Cortical thickness may in part reflect the amount of complex
connections between nerve cells. In other words, thicker cortices are
likely to have more complex connections with consequences on cognitive
ability. A positive link between cortical thickness and cognitive
ability was detected in many areas of the frontal, parietal, temporal
and occipital lobes. The regions with the greatest relationship were
the 'multi-modal association' areas, where information converges from
various regions of the brain for processing.
"A principal finding of this study is that it supports a distributed
model of intelligence where multiple areas of the brain are involved
with cognitive ability difference instead of the view that there is
just one centre or structure important for intelligence differences in
the brain," says Dr. Sherif Karama, psychiatrist at the MNI and
co-investigator in the study. "Previous studies have shown a link
between intelligence differences and individual brain structure or
function. This is the first time that a correlation between a general
cognitive ability factor and essentially most, if not all, cortical
association areas is demonstrated in the same study."
A deeper insight into normal cognitive functioning and abilities is
an important first step in the understanding of cognitive decline
observed in the elderly as well as in those with various pathologies
ranging from multiple sclerosis to schizophrenia, depression and mental
retardation. Such an understanding may eventually lead to interventions
that may be able to prevent or alleviate the decline or complications
in cognitive function.
The project was funded by National Institute of Child Health and
Human Development, the National Institute on Drug Abuse, the National
Institute of Mental Health, and the National Institute of Neurological
Disorders and the Fonds de Recherché en Santé du Quebec (FRSQ).
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