Newswise — Scientists from Lancaster University, UK, and the University Medical Centre in Ljubljana, Slovenia, have published their discoveries in Brain Research Bulletin, stating that the correlation between neuronal activity and the brain's oxygenation is modified in older individuals.
The brain constitutes approximately 20% of the body's energy consumption, necessitating a close coordination between the brain and the cardiovascular system to ensure an adequate energy supply to different brain regions. To achieve this, multiple "neurovascular units" are responsible for nourishing the neurons.
Previously, non-invasively recording the functioning of these neurovascular units in living humans had not been accomplished. However, this milestone has now been reached by employing various measurement techniques combined with innovative analysis methods developed at Lancaster University.In this study, the blood oxygenation of the living brain was assessed using infrared light, which can effectively penetrate the skull. Simultaneously, the neuronal activity in the brain was monitored by measuring electrical signals on the scalp's surface.
The human body operates with a symphony of rhythms, with the heartbeat being one of the most familiar rhythms. Additionally, there are other essential rhythms, such as respiration, brain waves, and processes that regulate blood pressure and blood flow by modulating the diameter of blood vessels.
By conducting simultaneous measurements of oxygenation, brain electrical activity, respiration, and heart electrical activity, the researchers were able to capture various rhythms and their slight variations in timing. To assess the strength and coordination of these rhythms, they calculated their "phase coherence."
The findings reveal notable alterations in the magnitudes of oscillations in brain vasculature and brain waves within the older group. However, more prominently, they observed significant changes in the coherence between these rhythms, suggesting that the coordination between energy supply and demand in the brain is negatively impacted by aging.
As the global population continues to age, the prevalence of dementia is on the rise. Consequently, the significance of tracking treatment progress and monitoring disease advancement will become increasingly crucial in the future, particularly for evaluating new drugs targeted at Alzheimer's disease.
Professor Aneta Stefanovska from Lancaster University emphasized that this approach has the potential to non-invasively assess the decline of neurovascular function in normal aging and also to monitor the effectiveness of treatments or lifestyle modifications in various neurodegenerative conditions.
The findings hold the potential for a relatively straightforward and non-invasive approach to evaluating the brain's condition in healthy aging and various neurodegenerative disorders, including Alzheimer's disease.
The researchers included Juliane Bjerkan, Gemma Lancaster, Trevor Crawford, Peter McClintock and Aneta Stefanovska from Lancaster University and Bernard Meglič and Jan Kobal from the University Medical Centre in Ljubljana, Slovenia.
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