Warach S, Gur R C, Gur R E, Skolnick B E, Obrist W D, Reivich M
Department of Neurology, University of Pennsylvania, Philadelphia 19104.
J Cereb Blood Flow Metab. 1992 Jul;12(4):546-53. doi: 10.1038/jcbfm.1992.78.
We previously reported decreased mean CBF between consecutive resting conditions, ascribed to habituation. Here we address the regional specificity of habituation over three consecutive flow studies. Regional CBF (rCBF) was measured in 55 adults (12 right-handed men, 12 right-handed women, 14 left-handed men, 17 left-handed women), with the 133Xe inhalation technique, during three conditions: resting, verbal tasks (analogies), and spatial tasks (line orientation). Changes in rCBF attributable to the cognitive tasks were eliminated by correcting these values to a resting equivalent. There was a progressive decrease in mean rCBF over time, reflecting habituation. This effect differed by region, with specificity at frontal (prefrontal, inferior frontal, midfrontal, superior frontal) and inferior parietal regions. In the inferior parietal region, habituation was more marked in the left than the right hemisphere. Right-handers showed greater habituation than did left-handers. There was no sex difference in global habituation, but males showed greater left whereas females showed greater right hemispheric habituation. The results suggest that habituation to the experimental setting has measurable effects on rCBF, which are differently lateralized for men and women. These effects are superimposed on task activation and are most pronounced in regions that have been implicated in attentional processes. Thus, regional decrement in brain activity related to habituation seems to complement attentional effects, suggesting a neural network for habituation reciprocating that for attention.
我们之前报道过，连续静息状态下的平均脑血流量（CBF）下降，这归因于习惯化。在此，我们通过连续三项血流研究探讨习惯化的区域特异性。采用¹³³Xe吸入技术，在静息、语言任务（类比）和空间任务（直线定向）三种条件下，对55名成年人（12名右利手男性、12名右利手女性、14名左利手男性、17名左利手女性）的局部脑血流量（rCBF）进行了测量。通过将这些值校正为静息等效值，消除了认知任务引起的rCBF变化。随着时间推移，平均rCBF逐渐下降，反映出习惯化。这种效应因区域而异，在额叶（前额叶、额下回、额中回、额上回）和顶下叶区域具有特异性。在顶下叶区域，左侧半球的习惯化比右侧更明显。右利手比左利手表现出更强的习惯化。整体习惯化没有性别差异，但男性左侧半球习惯化更强，而女性右侧半球习惯化更强。结果表明，对实验环境的习惯化对rCBF有可测量的影响，男性和女性的这种影响在大脑半球的分布有所不同。这些影响叠加在任务激活之上，在与注意力过程相关的区域最为明显。因此，与习惯化相关的脑活动区域减少似乎补充了注意力效应，提示存在一个与注意力神经网络相互作用的习惯化神经网络。
