Previous research shows that people can use a cue to mentally prepare for a cognitive challenge. Cognition may be facilitated by a brain-state coupled to expectations about an upcoming cognitive challenge. These results suggest that people, in general, are able to tune their level of alertness to an upcoming task. However only deactivated brain regions tuned their level of activity to the expected task difficulty. Our study shows that phasic alertness is represented by activated as well as deactivated brain regions. Activation did not differ between the cues. This effect was most prominent in medial prefrontal gyrus, visual, and temporal cortices. Deactivation was significantly stronger for cues signaling difficult stimuli than for cues signaling easy stimuli. For both cue types, participants showed activation in a network associated with central executive function and deactivation in regions of the default mode network (DMN) and visual cortex. Performance was lower for difficult stimuli than for easy stimuli. Performance and brain activity were compared between these two levels. Twenty-two healthy volunteers performed a cued visual perception task with two levels of task difficulty. If people in general are able to tune their level of alertness, then an inability to tune may be linked to disease. We examine if and how phasic alertness can be tuned to the expected difficulty of an upcoming challenge.
The response to a cue has been defined as phasic alertness which is reflected in faster responses and increased activity in frontal, parietal, thalamic, and visual brain regions. 2Department of Neurology and Neurosurgery, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, Netherlands.1Department of Neurosurgery, Elisabeth-TweeSteden Hospital, Tilburg, Netherlands.