Changes in ageing brain using new techniques

The coordination between neuronal activity and brain oxygenation is different in older individuals, according to researchers studying brain activity.

The findings of the study were published in Brain Research Bulletin by scientists from Lancaster University, UK and the University Medical Centre in Ljubljana, Slovenia.

Since the brain consumes up to 20 per cent of the body's energy, the cardiovascular system and the brain must cooperate closely to guarantee that each component of the brain receives an adequate supply of energy. Numerous "neurovascular units" tasked with feeding the neurons accomplish this.

It has never been possible to non-invasively record the activity of these neurovascular units in a living human, but this has now been accomplished utilizing a variety of measurement techniques and cutting-edge processing tools created at Lancaster University.

The living brain’s blood oxygenation was measured using infrared light, which easily penetrates the skull. The neuronal activity in the brain is associated with electrical activity, which was simultaneously measured on the surface of the scalp.

The body is humming with rhythms, with the best-known rhythm being the heartbeat. Other rhythms include respiration, brain waves, and processes controlling blood pressure and blood flow by changing the diameter of blood vessels.

Simultaneously measuring oxygenation, brain electrical activity, respiration and electric activity of the heart let the researchers capture these rhythms and their imperfect timings. They then studied the strength of these rhythms and their coordination, by computing their “phase coherence”.

The results illustrate that the magnitudes of the oscillations in brain vasculature and the brain waves are altered in the older group. But more dramatic are changes in the coherence between them, indicating that the coordination between the energy supply and demand in the brain is adversely affected by age.

The world population is ageing and the incidence of dementia is increasing. Hence, the ability to follow up treatment and monitor disease progression will grow more and more important in the years to come, especially in the possibility of assessing new drugs for Alzheimer’s disease.

Professor Aneta Stefanovska from Lancaster University said: “The approach could thus be used for non-invasive evaluation of the decline of neurovascular function in normal ageing, as well as for monitoring the efficacy of treatment or lifestyle changes in a wide range of neurodegenerative disorders.

“The results promise a relatively simple and non-invasive method for assessing the state of the brain in healthy aging, and in neurodegenerative disorders such as Alzheimer’s disease.”