Prefrontal cortex activation mediates cognitive reserve alertness and attention in the Virtual Classroom: preliminary fMRI findings and clinical implications

摘要

The Virtual Classroom is an interactive virtual reality simulation of a classroom-learning task, allowing continuous performance assessment in the context of sleep and attention research. Audiovisual distractions can be incrementally manipulated to assess cognitive workload and performance vigilance. In this feasibility study, we sought to establish a neuroimaging correlate of previous pilot work using the Virtual Classroom paradigm to study performance decrements in alertness and sustained attention. We hypothesized a thalamocortical (TLC) network subserving alertness, primarily mediated by activation of prefrontal cortex under differing distraction levels. In a block design of alternating 1-minute blocks of high and low visual distraction during the Go-No-Go task embedded in the Virtual Classroom program we studied a single healthy adult subject, with whole brain analysis used to assess regional activations. Differential activation between low and high distraction load conditions was noted while performing the task. Specific regions displaying increased activation during high distraction included bilateral frontal polar cortex and prefrontal cortex (PFC). Differential bilateral Area-V5 activation was also noted during "high distraction" condition due to increased visual monitoring of distracters. This implies a probable neural mechanism of action for this and other "virtual" tasks requiring effortful cognition and vigilance which involves prefrontal cortex activation. Given the numerous CNS psychopathologies involving PFC dysregulation, this implies that the Virtual Classroom task may be useful as a "broad-spectrum" assessment tool of frontal lobe function.