Australian researchers say brain shape, not connectivity, impacts function

by Jacob Fuller

Lauren Dempsey, MS in Biomedicine and Law, RN, FISM News 

Researchers from Monash University in Australia believe that the shape of the brain contributes to its function, rather than the widely accepted idea that billions of neurons transmit signals to each other, allowing the different areas of the brain to communicate.

The study, which was published Wednesday in the journal Nature, details the hypothesis that the shape of the brain, specifically the size, curves, and grooves have an impact on influence on our thoughts, feelings, and behaviors.

THE STUDY

The team took MRI scans of 255 healthy individuals from the Human Connectome Project while the participants performed tasks like tapping their fingers or recalling images as well as spontaneous activity. They then analyzed the brain activity of 10,000 different brain maps measuring brain shape from thousands of experiments across the globe.

From this data, the researchers were able to create a computer model that simulated the way a brain’s shape and size impact brain waves and then compared that model to a pre-existing computer model of brain activity that supports the understanding that neuron connectivity drives brain function. Comparing the two models found that the new model, based on geometric eigenmodes, provided a more accurate reconstruction of the brain activity that was captured in MRI scans and brain activity maps.

Eigenmodes are the natural patterns of vibration or excitation within a system, where different parts of the system are all vibrating at the same frequency. Eigenmodes are most commonly used in physics and engineering, but have recently been used to study the brain.

Dr. Ben Fulcher, who leads the Dynamics and Neural Systems Group in the School of Physics and is a co-author on the paper, said “This work underscores the importance of collaboration across scientific disciplines — in this case between physics and neuroscience,” adding that “By analyzing the brain as a physical system we were able to capture and understand patterns hidden in its incredible complexity.”

Dr. James Pang, the study’s lead author and a research fellow at the university explained that the significance of brain shape is similar to rainfall making ripples in a pond, the size and shape of the pond helps determine the nature of those ripples. Wave-like patterns from brain activity are influenced by the three-dimensional shape of the brain.

“The geometry is pretty important because it guides how the wave would look, which in turn relates to the activity patterns that you see when people perform different tasks,” Pang sai.

While more research needs to be done, this new study helps to strengthen the idea that brain shape is very influential. Another benefit to this hypothesis is that measuring brain shape is easier than brain wiring. However, Pang said this research does not discredit the importance of understanding brain connectivity. Instead, it indicates the “geometry of the brain plays a more essential role in brain function.”

Pang and fellow researcher and co-author of the study, Professor Alex Fornito, wrote, “This new approach opens possibilities for studying how brain shape affects function through evolution, development, and ageing, and in brain disease.”

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