Whatmough Christine, Nikelski Jim, Monchi Oury, Chertkow Howard
Department of Neurology and Neurosurgery, McGill University, Montréal, Canada.
Hum Brain Mapp. 2008 Aug;29(8):922-30. doi: 10.1002/hbm.20438.
We examined the effect of semantic task repetition and of alternating between tasks on cerebral blood flow in three H(2) (15)O positron emission tomography experiments. We found that repeatedly performing semantic tasks resulted in a reduction in cerebral blood flow to the left temporal association cortex similar to that found in priming experiments even though here there was no repetition of stimuli. Although the same effect was found in two different tasks (word meaning judgments and picture naming), it was only present when the same task was repeated on consecutive scans and not when the subjects alternated from scan to scan between tasks. We propose that there is a neural efficiency which develops in the association cortex of the temporal lobe as a result of repeatedly performing a semantic task. This efficiency is abolished by interruptions such as performing a different task.
在三项采用H₂¹⁵O正电子发射断层扫描实验中，我们研究了语义任务重复以及任务间交替对脑血流量的影响。我们发现，重复执行语义任务会导致左侧颞叶联合皮质的脑血流量减少，这与启动实验中发现的情况类似，尽管此处没有刺激的重复。虽然在两项不同任务（词义判断和图片命名）中都发现了相同的效果，但只有在连续扫描中重复相同任务时才会出现这种效果，而当受试者在不同扫描之间交替执行任务时则不会出现。我们提出，由于反复执行语义任务，颞叶联合皮质会产生一种神经效率。这种效率会因诸如执行不同任务等干扰而被消除。
