An international team of researchers have discovered five genetic variants that influence the size of structures within the human brain.

Researchers led by Drs. Sarah Medland, Margie Wright, Nick Martin and Paul Thompson of the QIMR Berghofer Medical Research Institute in Australia discovered five new genetic variants that influenced the volumes of the putamen and caudate nucleus. They also found stronger evidence for three locations in the genome that influence the size of the hippocampus and intracranial areas of the brain. The strongest genetic effects were observed for the putamen.

"Those are brain regions that we know are involved in various psychiatric and neurodegenerative disorders. In trying to figure out the genetics that make them either larger or smaller, it could have great benefits for understanding mechanisms of these disorders," Dr. Jessica Turner, researcher and associate professor of psychology and neuroscience at Georgia State, said in a statement.

In the study, nearly 300 researchers analyzed genetic data and magnetic resonance imaging (MRI) scans from nearly 31,000 individuals from around the world. They evaluated genetic data from seven subcortical brain regions (nucleus accumbens, caudate, putamen, pallidum, amygdala, hippocampus and thalamus) and intracranial volume from MRI scans.

The goal was to determine how common genetic variants affect the structure of these seven subcortical brain regions, which are associated with memory, movement, learning and motivation. Changes in these brain areas can lead to abnormal behavior and predisposition to disease.

Previous research has shown the brain's structure is strongly shaped by genetic influences. Identifying genetic variants could provide insight into the causes for variation in human brain development and help to determine how dysfunction in the brain occurs.

The findings are detailed in the journal Nature.