4 T-fMRI study of nonspatial shifting of selective attention: Cerebellar and parietal contributions
4 T-fMRI study of nonspatial shifting of selective attention: Cerebellar and parietal contributions
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DOI：
10.1152/jn.1998.79.3.1535
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发表时间：
1998-03-01
影响因子：
2.5
通讯作者：
Hu, XP
中科院分区：
文献类型：
--
作者：
Le, TH;Pardo, JV;Hu, XP
研究人员用4特斯拉的功能性磁共振成像（fMRI）监测小脑和大脑后皮质的局部血氧含量，同时16名正常受试者在相同的视觉刺激下执行三项任务：注视;注意力集中在刺激物的形状或颜色上，并在试验过程中持续（持续的注意力）;和快速，连续转移的注意力之间的刺激形状或颜色的试验块（转移注意力）。刺激集中显示100 ms，然后是900 ms的中央固定标记。每个刺激都是红色或绿色显示的圆形或正方形。注意力转移需要在每次目标检测之后在颜色和形状信息之间进行切换，并且平均每三秒发生一次。受试者在检测到目标后按下反应键;记录反应时间和反应准确度。两个协议的T2* 加权回波平面成像进行了优化，一个表面线圈的小脑单独和其他体积线圈小脑和后部脑结构（顶叶，枕叶，和部分颞叶皮质）成像。由于小脑的功能磁共振成像特别容易受到心脏和呼吸波动的影响，新技术被应用于从生理噪声中分离大脑激活信号。生成功能激活图，用于对比I）对颜色的持续注意减去固定; 2）对形状的持续注意减去固定;以及3）转移注意减去持续注意（对颜色和形状;即，在试验区组之间求和）。与这些任务的容易程度一致，受试者在持续注意力和转移注意力期间的准确率均>80%。方差分析并没有显示出显着差异，在误报或真正的打击跨任何注意力条件。一个亚组的受试者的表现数据记录在10分钟的连续实践没有显示出显着的变化，随着时间的推移。持续关注颜色或形状的条件与注视条件的对比显示，枕叶和颞下区（布罗德曼区18、19和37）的双侧激活显著。前内侧小脑也显着激活同侧的手指用于响应。主要的兴趣比较，转移注意力的条件和持续注意力的条件之间的对比产生了显著的和可重复的激活：小脑外侧半球（镰状小叶：I脚前和I脚后;左I脚后）;小脑叶;后上级顶叶小叶（R和L）;楔叶和楔前叶（R和L）。
Regional blood oxygenation in the cerebellum and posterior cerebral cortices was monitored with functional magnetic resonance imaging (fMRI) at four Tesla while 16 normal subjects performed three tasks with identical visual stimulation: fixation; attention focused upon either stimulus shape or color and sustained during blocks of trials (sustained attention); and rapid, serial shifts in attention between stimulus shape or color within blocks of trials (shifting attention). The stimuli were displayed centrally for 100 ms followed by a central fixation mark for 900 ms. Each stimulus was either a circle or a square displayed in either red or green. Attention shifting required switching between color and shape information after each target detection and occurred on average once every three seconds. Subjects pressed a response key upon detecting the target; reaction time and response accuracy were recorded. Two protocols for T2*-weighted echo-planar imaging were optimized, one with a surface coil for the cerebellum alone and the other with a volume coil for imaging both cerebellum and posterior brain structures (parietal, occipital, and part of temporal cortices). Because fMRI of the cerebellum is particularly susceptible to cardiac and respiratory fluctuations, novel techniques were applied to isolate brain activation signals from physiological noise. Functional activation maps were generated for contrasts of I) sustained attention to color minus fixation; 2) sustained attention to shape minus fixation; and 3) shifting attention minus sustained attention (to color and shape; i.e., summed across blocks of trials). Consistent with the ease of these tasks, subjects performed with >80% accuracy during both sustained attention and shifting attention. Analysis of variance did not show significant differences in false alarms or true hits across either attentional condition. A subgroup of subjects whose performance data were recorded during ten minutes of continuous practice did not show significant changes over time. Both contrasts between the conditions of sustained attention to color or to shape as compared with the fixation condition showed significant bilateral activation in occipital and inferior temporal regions (Brodmann areas 18, 19, and 37). The anterior medial cerebellum was also significantly activated ipsilateral to the finger used for responding. The principal comparison of interest, the contrast between the condition of shifting attention and the condition of sustained attention produced significant and reproducible activation: lateral cerebellar hemisphere (ansiform lobule: Crus I Anterior and Crus I Posterior; left Crus I Posterior); cerebellar folium; posterior superior parietal lobule (R and L); and cuneus and precuneus (R and L).