Stevens Michael C, Calhoun Vince D, Kiehl Kent A
Olin Neuropsychiatry Research Center, The Institute of Living, Hartford, CT 06106, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA.
Neuroimage. 2005 Jul 1;26(3):782-92. doi: 10.1016/j.neuroimage.2005.02.044. Epub 2005 Apr 7.
Evidence from neuroimaging studies suggests that the right hemisphere of the human brain might be more specialized for attention than the left hemisphere. However, differences between right and left hemisphere in the magnitude of hemodynamic activity (i.e., 'functional asymmetry') rarely have been explicitly examined in previous neuroimaging studies of attention. This study used a new voxel-based comparison method to examine hemispheric differences in the amplitude of the hemodynamic response in response to infrequent target, infrequent novel, and frequent standard stimuli during an event-related fMRI auditory oddball task in 100 healthy adult participants. Processing of low probability task-relevant target stimuli, or 'oddballs', and low probability task-irrelevant novel stimuli is believed to engage in orienting and attentional processes. It was hypothesized that greater right-hemisphere activation compared to left would be observed to infrequent target and novel stimuli. Consistent with predictions, greater right hemisphere than left frontal, temporal, and parietal lobe activity was observed for target detection and novelty processing. Moreover, asymmetry effects did not differ with respect to age or gender of the participants. The results (1) support the proposal that the right hemisphere is differentially engaged in processing salient stimuli and (2) demonstrate the successful use of a new voxel-based laterality analysis technique for fMRI data.
神经影像学研究的证据表明，人类大脑右半球在注意力方面可能比左半球更为专门化。然而，在以往关于注意力的神经影像学研究中，很少明确考察左右半球在血液动力学活动幅度上的差异（即“功能不对称”）。本研究采用一种基于体素的新比较方法，在100名健康成年参与者进行的事件相关功能磁共振成像听觉oddball任务中，考察对罕见目标、罕见新异刺激和频繁标准刺激做出反应时，血液动力学反应幅度的半球差异。处理低概率的与任务相关的目标刺激（即“oddball”）以及低概率的与任务无关的新异刺激，被认为涉及定向和注意力过程。研究假设，相对于左半球，右半球对罕见目标和新异刺激的激活更强。与预测一致，在目标检测和新异性处理方面，观察到右半球比左半球在额叶、颞叶和顶叶的活动更强。此外，不对称效应在参与者的年龄或性别方面没有差异。这些结果（1）支持了右半球在处理显著刺激方面有差异地参与的观点，（2）证明了一种基于体素的新的功能磁共振成像数据偏侧性分析技术的成功应用。
