Task-specific connectivity from human Frontal Eyefields, as revealed by combined TMS and fMRI
Neural processes underlying selective attention are thought to involve extended networks rather than single brain areas. The frontal eyefields (FEF) constitute important nodes of the dorsal attention network and are proposed to represent a ‘salience map’ guiding top-down selection by prioritizing task-relevant sensory information. But what are the mechanisms through which the FEF interacts with other contributing areas in the network and sensory cortex during selective attention?
Causal evidence for attentional modulation by the FEF of activity in the sensory cortex was first emerging from physiological studies in monkeys, but is now also provided by several human studies using multimodal approaches, combining TMS with fMRI or EEG. These studies corroborated the FEF as a source of modulatory signals on visual cortex and, importantly, revealed task-specific signal transmission. So far this has mainly been shown in the context of spatial attention.
During this presentation I discuss two recent studies in which we extended the application of this multimodal approach to other types of attention. We combined TMS with fMRI (either concurrent or off-line) to show causal impact of signal transmission emanating from FEF on attention networks in I) a feature attention task and II) an attention shifting paradigm.