Hairston W David, Hodges Donald A, Casanova Ramon, Hayasaka Satoru, Kraft Robert, Maldjian Joseph A, Burdette Jonathan H
ANSIR Lab, Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27257, USA.
Neuroreport. 2008 Jan 22;19(2):151-4. doi: 10.1097/WNR.0b013e3282f42509.
Blood oxygen-level-dependent signal decreases relative to baseline (deactivations) can occur with stimulation of an opposing sensory modality. Here, we show the importance of the difficulty of an auditory task on the deactivation of visual cortical areas. Participants performed an auditory temporal-order judgment task in conjunction with sparse-sampling functional MRI at both moderate and high levels of difficulty (adjusted for each individual's own threshold). With moderate difficulty, small deactivations were observed not only in parietal and cingulate cortex, but occipital cortex as well. When the same task was more difficult, deactivations increased significantly to include a greater extent of functionally defined visual cortex. Together, these results suggest that cross-modal deactivations occur in compensation for task difficulty, perhaps acting as an intrinsic filter for nonrelevant information.
相对于基线的血氧水平依赖信号降低（失活）可能会在对相反感觉模态的刺激时出现。在此，我们展示了听觉任务难度对视觉皮层区域失活的重要性。参与者在中等和高难度水平（根据每个个体自身的阈值进行调整）下，结合稀疏采样功能磁共振成像执行听觉时间顺序判断任务。在中等难度时，不仅在顶叶和扣带皮层观察到小的失活，枕叶皮层也有。当相同任务难度增加时，失活显著增加，涉及功能定义的视觉皮层的更大范围。总之，这些结果表明跨模态失活是为补偿任务难度而发生的，可能作为对无关信息的一种内在过滤机制。
