Secrets about how variations in our genes impact on the development of the size and structure of our brains have been unlocked by a new study involving an international group of hundreds of scientists, including some based in Ireland.

It is hoped the research could lead to a better understanding of how neurological disorders like schizophrenia, Alzheimer's disease and epilepsy develops.

The study, which involved a consortium of almost 300 scientists from 193 institutions globally, saw genetic data and MRI scans collected from 30,717 people around the world analysed and shared.

In particular the group studied the parts of the brain involved in basic functions like memory, movement, learning and motivation.

In patients with neurological illnesses, these are the areas of the brain which normally show abnormalities.

The group found a series of five genetic variations that can impact on these regions, often during the process of brain development.

The largest genetic association found by the study related to the Putamen - a small fruit stone sized region near the brain's centre partly responsible for movement and learning.

The group found a genetic variant connected to the area, which is also connected to Parkinson's disease.

Other variations were found to be linked to changes in the volume of the hippocampus - a key region involved in learning and memory which is also known to be associated with schizophrenia.

A group of scientists at NUI Galway, led by Professor of Psychology Gary Donohoe, participated in the project, known as Enhancing Neuro Imaging Genetics through Meta-Analysis (ENIGMA).

Scientists at Trinity College Dublin were also involved in the consortium, with part of the funding coming from Science Foundation Ireland and the Health Research Board.

The research, published in Nature, is being described as crowd sourced science, because of the huge volumes of data, large numbers of people and the significant levels of collaboration involved in carrying out.

Research on such a scale is usually very expensive, but in this case because of the huge amount of scientists taking part the costs were shared across institutions.

"Knowledge about the genetic basis of these structures provides important insights into how the brain develops", said Professor Donohoe in a statement.

"These insights are important both to understanding normal human development and to understanding the basis of neurodevelopmental and neurodegenerative disorders such as schizophrenia, Alzheimer's disease and epilepsy.

"Given the likelihood that thousands of variants are involved, large scale international efforts such as in this study are an important step in unravelling this genetic and biological complexity so as to develop new and better treatments."