Mental Health Clinical Research Center, Department of Psychiatry, University of Iowa Hospitals and Clinics, University of Iowa, Iowa City, Iowa 52242-1057, USA.
Hum Brain Mapp. 1997;5(6):422-36. doi: 10.1002/(SICI)1097-0193(1997)5:6<422::AID-HBM3>3.0.CO;2-5.
Brain mechanisms involved in the maintenance of attention to auditory and visual stimuli at different spatial locations were assessed using positron emission tomography with [15O]water to measure regional cerebral blood flow (rCBF) changes in 13 normal volunteers. Simultaneous auditory [dichotically presented consonant-vowel-consonants (CVCs)] and visual stimuli (vertically oriented, CVCs presented to the left and right of fixation) were presented on every trial. In different conditions subjects attended for targets in a specified stimulus channel (left or right ears or left or right visual fields) while maintaining fixation on a central x. Attending left or right for auditory stimuli increased rCBF in primary auditory cortex in Heschl's gyrus and in temporal lobe auditory association cortices in both hemispheres. Attending left or right for visual stimuli did not change rCBF in primary visual cortex, and only attention to the right significantly increased rCBF in contralateral occipital cortex. Visual attention caused significant rCBF changes in a widespread network that included frontal, parietal, and temporal cortical regions as well as the cerebellum, whereas rCBF changes due to auditory attention were largely localized in the temporal lobes. The results suggest that spatially directed attention is mediated by different mechanisms in the auditory and visual modalities.
使用正电子发射断层扫描（PET）技术，通过测量[15O]水的区域脑血流（rCBF）变化，评估了在不同空间位置上维持对听觉和视觉刺激的注意力的大脑机制。13 名正常志愿者参与了研究。在每一次试验中，同时呈现听觉（双声道呈现的辅音-元音-辅音（CVC））和视觉刺激（垂直呈现，CVC 呈现在注视点的左右两侧）。在不同的条件下，被试者需要注意特定刺激通道（左右耳或左右视野）中的目标，同时保持注视中央 x。注意听觉刺激的左右侧会增加两侧半球的初级听觉皮层和颞叶听觉联合皮层中的 rCBF。注意视觉刺激的左右侧不会改变初级视觉皮层中的 rCBF，只有注意右侧会显著增加对侧枕叶皮层中的 rCBF。视觉注意力会引起广泛的 rCBF 变化，包括额叶、顶叶和颞叶皮质区域以及小脑，而听觉注意力引起的 rCBF 变化则主要局限于颞叶。研究结果表明，空间定向注意力在听觉和视觉模式中由不同的机制介导。
