Scans and DNA combine to help understand brain development

Three research groups in Ireland have contributed to a major international study to understand how small differences in brain structure may contribute to mental health problems.

The study in terms of numbers was enormous but had to be so in order to succeed, said Prof Gary Donohoe, NUI Galway professor of psychology. It involved 30,000 people worldwide in a project called Enigma, Enhancing Neuroimaging Genetics Through Meta-Analysis.

There were almost 300 scientists from 193 institutes including NUIG, Trinity College Dublin and the Royal College of Surgeons in Ireland, Prof Donohoe said.

The project involved taking brain scans of all the participants, making it possible to compare the size of brain structures, he said. The scientists then mapped the DNA of the participants allowing them to match up DNA against the structures, looking for any links between the two.

“We know how the brain forms, the steps in this and the organisation of the brain but there are lots of things we don’t know,” said Prof Donohoe.

Variations

Small variations in parts of the brain occur and genes in the DNA cause this to happen, but the effects of this are very small.

“In order to test the effect you need thousands and thousands of participants,” he said. This included healthy people and ill, those with neurodevelopmental and with mental health problems and also degenerative diseases.

The researchers looked at brain structures involved with memory, movement, learning and motivation.

“We were trying to understand some of the unknown biology that affects neurodevelopment. The more data you have, the more accurate the assessment of the underlying architecture of the brain.”

Research

The research was published in the journal

Nature

.

Science Foundation Ireland

and the

Health Research Board

part-funded the research here.

So far the study has revealed five genetic variants that influence the size of certain brain structures, a real accomplishment given the vast amount of information that must be collected and then analysed by computers and the scientists.

One relates to the hippocampus, a structure linked to memory. The size of the structure has been implicated in Alzheimer’s disease and schizophrenia, Prof Donohoe said.

“We will take some of these early results and start to learn more about them, looking in particular at the hippocampus.”