Research projects

Background: How is the brain supplied with food for thoughts?
And what goes wrong when we age, or suffer from a neurodegenerative disorder?

Normal brain function depends on preserved supply of glucose and oxygen and even minor deficits in control of the cerebral circulation lead to loss of brain function. The robust coupling between brain activity and cerebral blood flow (CBF), the so-called neurovascular coupling regulates the minor local CBF alterations that take place all the time. In the past, the dynamics of CBF control was based on an understanding of brain arterioles and on capillaries for exchange of substances between blood and brain.  This notion has undergone an important change in recent years because it has been discovered that both arterioles and capillaries take part in 1) substance exchange and 2) cerebrovascular resistance. 

 

 

More details on our projects

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Project participants
Project description

Population prognostics show that by the year 2030, 29% of the Danish population will be 60+ years compared to 24% today and that much of this increase will be due to increased numbers of persons 80 years of age or more. Similar aging populations are seen world-wide. With this shift in population demographics, there is also increased prevalence of diseases related to aging.  Why is age a risk factor for sustained damage following slight head trauma in the elderly and what mechanisms in brain ageing makes the brain frail and predisposes to neurodegenerative diseases such as Alzheimer’s disease? That is the question. 

Our first study showed that a concerted action among astrocytes in aged brains giving rise to astroglial calcium waves. These waves were abundant in old but not young brains and evoked small but repeated rises in oxygen consumption. This is one brain ageing mechanism with the potential to reduce brain's oxidative reserve capacity and thereby contribute to brain frailty.

Healthy brain aging is also characterized by reduced cerebral blood flow (CBF) and reduced responses to rises in neuronal activity – the supply of food for thought is restricted and even when the need goes up supply is at the borderline of being insufficient. Our second study reported that this was strongly correlated to reduced spontaneous and evoked gamma activity, which is strongly linked to perception, cognition and memory is humans as well as rodents. Gamma oscillations may drive the mechanisms responsible adjusting blood flow to brain activity, which decrease with age.  In contrast, the coupling between metabolism and activity increase with age, despite reduced gamma oscillations in old animals.  This could suggest that gamma activity and the interneurons that produce them are key players in healthy brain aging.

In our current project we use mice with parvalbumine (PV) positive interneurons that can be stimulated by light, so called optogenetic stimulation. This research project is believed to shed light on the importance of this particular type of interneuron in vascular and metabolic regulation in young and old mice.