Brain Shape Affects its Functioning

For more than a century, scientists have believed that the patterns of brain activity that define our experiences, hopes, and dreams are governed by how various brain regions communicate with one another via a complicated web of trillions of cellular connections.

A new study led by Monash University’s Turner Institute for Brain and Mental Health researchers has examined over 10,000 different maps of human brain activity and discovered that the overall shape of a person’s brain has a far greater influence on how we think, feel, and behave than its intricate neuronal connectivity.

The study, published in the journal Nature, combines methodologies from physics, neurology, and psychology to challenge the century-old paradigm that emphasizes the importance of intricate brain connectivity, instead discovering a previously unknown association between brain structure and activity.

The discoveries, according to lead author and Research Fellow Dr. James Pang of the Turner Institute and Monash University’s School of Psychological Sciences, are noteworthy because they considerably simplify how we may investigate how the brain functions, develops, and matures.

The work opens opportunities to understand the effects of diseases like dementia and stroke by considering models of brain shape, which are far easier to deal with than models of the brain’s full array of connections,” Dr. Pang said.

“We have long thought that specific thoughts or sensations elicit activity in specific parts of the brain, but this study reveals that structured patterns of activity are excited across nearly the entire brain, just like the way in which a musical note arises from vibrations occurring along the entire length of a violin string, and not just an isolated segment,” he said.

The researchers studied eigenmodes using magnetic resonance imaging (MRI), which are the natural patterns of vibration or excitation in a system in which different components of the system are all excited at the same frequency. Eigenmodes are often employed to examine physical systems in fields such as physics and engineering, and they have only lately been modified for use in studying the brain.

The goal of this research was to find the most efficient approach to create the brain’s eigenmodes.

“Just as the resonant frequencies of a violin string are determined by its length, density and tension, the eigenmodes of the brain are determined by its structural––physical, geometric and anatomical––properties, but which specific properties are most important has remained a mystery,” said co-lead author, Dr. Kevin Aquino, of BrainKey and The University of Sydney.