Cognitive Neuroscience Talks
The BOLD signal: interpretations and limitations
Functional MRI relies usually on oxygenation changes, i.e. on the BOLD signal. However, the relationship between this signal and the neural activity is not straightforward. Indeed, the BOLD signal is a very indirect measurement of brain activity with complex underlying interactions between vasculature, oxygen consumption and metabolism. Reviewing briefly the BOLD physiology one can understand that fMRI has spatial and temporal limitations and that it can NOT detect all cognitive/brain changes.