Guerreiro Maria J S, Anguera Joaquin A, Mishra Jyoti, Van Gerven Pascal W M, Gazzaley Adam
University of California, San Francisco.
J Cogn Neurosci. 2014 Dec;26(12):2827-39. doi: 10.1162/jocn_a_00685. Epub 2014 Jul 10.
Selective attention involves top-down modulation of sensory cortical areas, such that responses to relevant information are enhanced whereas responses to irrelevant information are suppressed. Suppression of irrelevant information, unlike enhancement of relevant information, has been shown to be deficient in aging. Although these attentional mechanisms have been well characterized within the visual modality, little is known about these mechanisms when attention is selectively allocated across sensory modalities. The present EEG study addressed this issue by testing younger and older participants in three different tasks: Participants attended to the visual modality and ignored the auditory modality, attended to the auditory modality and ignored the visual modality, or passively perceived information presented through either modality. We found overall modulation of visual and auditory processing during cross-modal selective attention in both age groups. Top-down modulation of visual processing was observed as a trend toward enhancement of visual information in the setting of auditory distraction, but no significant suppression of visual distraction when auditory information was relevant. Top-down modulation of auditory processing, on the other hand, was observed as suppression of auditory distraction when visual stimuli were relevant, but no significant enhancement of auditory information in the setting of visual distraction. In addition, greater visual enhancement was associated with better recognition of relevant visual information, and greater auditory distractor suppression was associated with a better ability to ignore auditory distraction. There were no age differences in these effects, suggesting that when relevant and irrelevant information are presented through different sensory modalities, selective attention remains intact in older age.
选择性注意涉及对感觉皮层区域的自上而下的调节，使得对相关信息的反应得到增强，而对无关信息的反应则受到抑制。与对相关信息的增强不同，对无关信息的抑制在衰老过程中已被证明存在缺陷。尽管这些注意机制在视觉模态中已得到充分表征，但当注意力在不同感觉模态之间选择性分配时，人们对这些机制却知之甚少。本脑电图研究通过在三项不同任务中测试年轻和年长参与者来解决这个问题：参与者专注于视觉模态而忽略听觉模态、专注于听觉模态而忽略视觉模态，或被动地感知通过任何一种模态呈现的信息。我们发现，在两个年龄组的跨模态选择性注意过程中，视觉和听觉处理都存在整体调节。在听觉干扰的情况下，视觉处理的自上而下调节表现为视觉信息增强的趋势，但当听觉信息相关时，视觉干扰没有显著抑制。另一方面，在视觉刺激相关时，听觉处理的自上而下调节表现为对听觉干扰的抑制，但在视觉干扰的情况下，听觉信息没有显著增强。此外，更大程度的视觉增强与对相关视觉信息的更好识别相关，更大程度的听觉干扰抑制与忽略听觉干扰的更好能力相关。这些效应不存在年龄差异，这表明当相关和无关信息通过不同感觉模态呈现时，老年人的选择性注意仍然完好无损。
