Linking band-limited cortical population activity to fMRI and behavior

This chapter addresses the relationship of band-limited electrophysiological mass activity to behavior on the one hand, and to the BOLD fMRI signal on the other. Electrophysiological mass activity generally reflects several different components of neuronal activity, which are generated by distinct neural mechanisms and expressed in different frequency ranges. The relative strengths of these components thus determine a so-called specific spectral fingerprint of a perceptual or cognitive process. A striking discrepancy between the spectral fingerprint of stimulus-driven responses in sensory cortices and the fingerprints of intrinsic processes (such as top-down attention or switches between perceptual states) within the same cortical areas is highlighted. It is proposed that this dissociation reflects recurrent interactions between distant cortical areas and/or neuromodulation of cortical activity patterns by ascending systems, which are both thought to play an important role in such processes.