Center for Brain/Mind Medicine, Division of Cognitive and Behavioral Neurology, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA.
Brain Res. 2013 Mar 7;1499:69-79. doi: 10.1016/j.brainres.2013.01.003. Epub 2013 Jan 8.
Selective attention reflects the top-down control of sensory processing that is mediated by enhancement or inhibition of neural activity. ERPs were used to investigate age-related differences in neural activity in an experiment examining selective attention to color under Attend and Ignore conditions, as well as under a Neutral condition in which color was task-irrelevant. We sought to determine whether differences in neural activity between old and young adult subjects were due to differences in age rather than executive capacity. Old subjects were matched to two groups of young subjects on the basis of neuropsychological test performance: one using age-appropriate norms and the other using test scores not adjusted for age. We found that old and young subject groups did not differ in the overall modulation of selective attention between Attend and Ignore conditions, as indexed by the size of the anterior Selection Positivity. However, in contrast to either young adult group, old subjects did not exhibit reduced neural activity under the Ignore relative to Neutral condition, but showed enhanced activity under the Attend condition. The onset and peak of the Selection Positivity occurred later for old than young subjects. In summary, older adults execute selective attention less efficiently than matched younger subjects, with slowed processing and failed suppression under Ignore. Increased enhancement under Attend may serve as a compensatory mechanism.
选择性注意反映了感觉处理的自上而下的控制，这种控制是通过增强或抑制神经活动来实现的。本研究使用事件相关电位（ERP）技术，在一个实验中检查了选择性注意颜色的年龄相关差异，该实验在注意和忽略条件下以及在中性条件下（颜色与任务无关）进行。我们试图确定老年和年轻成年受试者之间的神经活动差异是否是由于年龄差异而不是执行能力差异所致。根据神经心理学测试表现，老年受试者与两组年轻受试者相匹配：一组使用适合年龄的标准，另一组使用未经年龄调整的测试分数。我们发现，在 Attend 和 Ignore 条件之间的选择性注意的整体调制方面，老年和年轻受试者组之间没有差异，这可以从前部选择正性的大小来衡量。然而，与任何一个年轻成年组都不同的是，老年受试者在忽略条件下的神经活动没有相对于中性条件减少，反而在 Attend 条件下表现出增强的活动。选择正性的起始和峰值在老年组比年轻组晚。总之，与匹配的年轻受试者相比，老年人执行选择性注意的效率较低，在忽略条件下处理速度较慢，且抑制失败。Attend 下的增强可能是一种补偿机制。
