Dominant rhythms of the brain slow down with healthy ageing but communication among brain regions prevails. Credit: Anagh Pathak

Neuroscientists have discovered that the slowing of the peak alpha frequency in the brains of elderly people is not necessarily a sign of a brain disorder1. Instead, scans reveal how a human brain preserves neuronal communication despite age-related neurodegenration.

Alpha waves form in healthy, awake adults while they rest with closed eyes. They disappear during sleep or when concentrating on a specific task.

To combat age-induced wear and tear, human brains have innate repair mechanisms to help maintain the neurons’ ability to communicate. However, the complexity of brain dynamics makes it difficult to decipher the repair process.

To identify markers and mechanisms of neural repair, scientists at the National Brain Research Centre in Haryana and the Indian Institute of Technology in Jodhpur analysed open-access brain-scan data of young and elderly individuals. The researchers, led by Arpan Banerjee, tracked synchrony in oscillating neurons in different brain regions. It allowed them to measure how brain regions coordinate with one another.

The team, which included Anagh Pathak and Dipanjan Roy, found that alpha waves synchrony remains during healthy lifespan ageing. A computer model of the whole brain showed that neural coordination can be preserved, even as the speed at which brain regions communicate with each other slows down.

Their model suggests that, like various cancers, brain disorders may arise from failures of repair mechanisms rather than direct structural damage. The researchers want to test this idea on data from neurodegenerative disorders with patient-specific mapping that can detect delays in neural communication.