Topographical analysis of cortical evoked activity during a variable demand spatial processing task.
This experiment studied changes in brain activity as subjects performed a variable demand spatial rotation task. The task involved the sequential presentation of a template histogram and a spatially rotated comparison histogram. Task difficulty was manipulated by varying the number of bars and the degree of rotation. Topographical analysis of the brain event-related activity data indicated the presence of negative components that were maximal at the vertex within 80 ms and bilaterally in the temporal lobes within 140 ms of stimulus onset and that appeared to be insensitive to changes in task difficulty. Demand-sensitive potentials were recorded, however. Positive components corresponding to P200 and P300 activity were recorded symmetrically around site PZ. The P200 component declined in amplitude, but showed no changes in latency as task demand increased. P300 activity declined in both amplitude and latency as the task became more difficult. Finally, a positive component was recorded over right central cortex approximately 490 ms after stimulus onset. This component declined in amplitude but increased in latency as task difficulty increased.
Wilson
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Performance Assessment Branch, Armstrong Laboratory, Wright-Patterson AFB, Dayton, OH 45433-7022.
Swain
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RA
Davis
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I
D000328:Adult; D000337:Aerospace Medicine; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D005071:Evoked Potentials; D006801:Humans; D008297:Male; D008606:Mental Processes / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012399:Rotation; D013028:Space Perception / Q000502:physiology*; D013647:Task Performance and Analysis