دانلود رایگان مقاله ارتباط الکتروفیزیولوژیک ضعیف و محفوظ توجه فضایی بصری در افراد مسن

ABSTRACT

Healthy aging is associated with changes in many neurocognitive functions. While on the behavioral level, visual spatial attention capacities are relatively stable with increasing age, the underlying neural processes change. In this study, we investigated attention-related modulations of the stimulus-locked event-related potential (ERP) and occipital oscillations in the alpha band (8–14 Hz) in young and elderly participants. Both groups performed a visual attention task equally well and the ERP showed comparable attention-related modulations in both age groups. However, in elderly subjects, oscillations in the alpha band were massively reduced both during the task and in the resting state and the typical task-related lateralized pattern of alpha activity was not observed. These differences between young and elderly participants were observed on the group level as well as on the single trial level. The results indicate that younger and older adults use different neural strategies to reach the same performance in a covert visual spatial attention task

4. Discussion

In this experiment, we investigated spatial attention-related ERPs and occipital alpha activity in younger and elderly subjects. In this relatively easy task, both groups performed at ceiling level. But while ERP responses to targets and non-targets were similar for both age groups, alpha power and alpha lateralization were significantly reduced in older adults. Our results are in line with previous research on age-related changes in the ERP [5,9,18,34,43] and in alpha lateralization [21], even with a task that is different from previous studies. To the latter case we can add that not just alpha lateralization, but alpha power itself is diminished in older adults. Finally, classification analysis indicates that the direction of attention can be reliably decoded from single trial ERPs in both age groups, but decoding based on alpha lateralization is compromised in elderly subjects. In contrast to the young subjects, elderly subjects demonstrated task-related lateralized power modulation at higher frequencies. This pattern of activity was consistently present on the single trial level. Although this might suggest a form of compensatory activity in the elderly, chances are high that this is muscle rather than brain activity.