Implications for interpreting brain disorders
According to Riedl, these insights also affect the interpretation of research findings in brain disorders: “Many fMRI studies on psychiatric or neurological diseases – from depression to Alzheimer’s – interpret changes in blood flow as a reliable signal of neuronal under- or over-activation. Given the limited validity of such measurements, this must now be reassessed. Especially in patient groups with vascular changes – for instance due to aging or vascular disease – the measured values may primarily reflect vascular differences rather than neuronal deficits.” Previous animal studies already point in this direction.
The researchers therefore propose complementing the conventional MRI approach with quantitative measurements. In the long term, this combination could form the basis for energy-based brain models: rather than showing activation maps that depend on assumptions about blood flow, future analyses could display values indicating how much oxygen – and therefore energy – is actually consumed for information processing. This opens new perspectives for examining aging, psychiatric, or neurodegenerative diseases in terms of absolute changes in energy metabolism – and for understanding them more accurately.