'Brain scans may help detect neurological, psychiatric disorders'

A scan which shows how brain regions interact may help diagnose migraines, depression, bipolar disorder and many other ailments of the brain, scientists say.

A study published in the journal Neuron shows that a kind of brain scan called functional connectivity MRI (fcMRI) can reliably detect fundamental differences in how individual brains are wired.

The technique could potentially be used to distinguish healthy people from those with brain diseases or disorders, and provide insight into variations in cognitive ability and personality traits.

"This is a step towards realising the clinical promise of functional connectivity MRI," said Steven Petersen, a professor at the Washington University School of Medicine in the US.

"Before we can develop diagnostic tests based on fcMRI, we need to know what it is actually measuring. We show here that it's not measuring what you're thinking, but how your brain is organised. That opens the door to an entire new field of clinical testing," Petersen said.

Researchers analysed data from more than 10 hours of fcMRI scans on nine people, collected in 10 separate one-hour sessions for each person.

During the scans, each person performed tasks related to vision, memory, reading or motor skills, or rested quietly.

Functional MRI scans generate a dynamic map of the outer surface of the brain, showing changing hot spots of activity over time.

To create a functional connectivity map, postdoctoral researcher Caterina Gratton divided the brain's surface into 333 regions and identified areas that became active and inactive in unison.

She then constructed brain network maps for each individual, showing patterns of correlation between parts of the brain.

The sheer quantity of data available on each person allowed her to analyse how much an individual's brain networks changed from day to day and with different mental tasks.

"Brain networks captured by fcMRI are really about the individual," Gratton said.

"Whether someone's watching a movie or thinking about her breakfast or moving her hands makes only a small difference. You can still identify that individual by her brain networks with a glance," she said.

The consistency of the fcMRI scans makes them a promising diagnostic tool, researchers said.

Although the technique's potential to identify brain disorders and diseases was noted years ago, fcMRI-based diagnostic tests have yet to make their way into doctors' offices.

Progress has been stymied by confusion over whether the scans reflect fundamental, stable features of the brain, or if they change with every passing thought.

The researchers found that the technique was powerful enough to distinguish people who were extraordinarily alike.