Brain-Evoked Potential Study of Task Difficulty Using Verbal Memory and MentalRotation Tasks

摘要

Different task processing requirements may produce different patterns of brainevoked potential (EP) variation with changes in task difficulty. We examined and compared EP changes associated with variable task difficulty in two dissimilar tasks: (1) the auditory Sternberg memory task, and (2) a visuo-spatial mental rotation task. EPs were submitted to source derivation and evaluated for changes related to increased central processing difficulty. Mid-latency EP amplitudes were differentially sensitive to changes in memory search (Sternberg) or perceptual complexity (mental rotation). The amplitude of a later endogenous component varied with task difficulty in both tasks, but demonstrated unique topographic distributions as well as unique pattern changes. These findings support the view that task difficulty effects on EPs are observable as changes to both mid-and long-latency components, but that these changes may differ with the processing requirements of different tasks.... Evoked potentials, Task difficulty, Electrical brain topography, Workload.