DOES BOLD fMRI REVEAL PSEUDO NEURONAL ACTIVITY?
Cognitive Neuroscience depends on a proper interpretation of brain imaging signals. Former interpretation has been simple, comparing number of spiking neurons with average BOLD signals (i.e. Rees, Friston, Koch 2000, Nat Neurosci.). What is the state-of-the art interpretation of BOLD today? Results of Sirotin and Das (2009, Nature; and Devor et al. 2008, JNS) have questioned the simple interpretation of BOLD by providing evidence for BOLD-signal without neuronal activity. Is there a non-neuronal source for the BOLD signal? Is there a brain activity signal that is missed by electrophysiology? Does an activated region reflect activation in this region or elsewhere (e.g. in the form of feedback)? How should state-of-the-art models of neurovascular coupling affect the interpretation of brain imaging data? (Logothetis 2008, Nature Reviews; Viswanathan and Freeman 2007, Nat Neurosci.; Lauritzen 2005 Nature Reviews).