A large international study has identified variations in the human genome that influence the size of structures deep within the brain.
The research offers an insight into why different sub-cortical areas of the brain are larger in some people than others, and could throw light on why some people develop conditions such as schizophrenia, Alzheimer’s disease and Tourette’s syndrome.
“Many neuropsychiatric diseases and conditions, like depression and schizophrenia have effects on the regions we’ve studied, says study co-author Dr Sarah Medland from Brisbane’s QIMR Berghofer Medical Research Institute.
“Improving our understanding of how these structures develop and how they function might help us work out where changes of those structures are coming from in those diseases,” says Medland.
The meta-analysis using data from 193 institutions from around the globe (which together form a consortium called ENIGMA) appears in the latest edition of Nature.
The data was derived from genetic studies and MRI scans from more than 30,000 people.
“Each of the research groups involved in the study ran the same sequence of analyses on the data they had collected. We’ve combined the results of these analyses generating one of the largest imaging genetics studies to date,” says Medland.
The research concentrated on seven structures within the brain that play important roles in everyday behaviours such as learning and memory.
It also looked at a measure of overall brain size.
“We wanted to see if we could find some of the genetic variants that influence how those structures form in the general population,” says Medland.
“Once we’ve got a better understanding of what a normally developing brain looks like, we hope it will be easier to identify how diseases might influence these areas.”
One of the areas of the brain the research looked at was the putamen, which is involved in body movements and learning. The research identified several genetic variants that influenced the size of this structure.
Others were shown to influence the overall size of brain and the hippocampus, a structure associated with spatial navigation and memory.
Genetic variants were also identified that appeared to influence the size of the amygdala (associated with memory, emotion and decision-making), and the caudate nucleus (linked to both voluntary movement and learning as well as memory, sleep, emotions and language).
Medland says the study demonstrates that a collaborative analysis of genetic and imaging data can identify relationships between genetic variants and human brain development and dysfunction.
“Research of this kind is prohibitively expensive for one institution to do, and none of this work would be possible without all of the input from scientists and participants from around the world.”
Tags: alzheimers-and-dementia, parkinsons-disease, neuroscience, genetics, psychosis