Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Psychology, Auburn University, Auburn, AL, USA.
Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Neurobiol Aging. 2020 Jul;91:125-135. doi: 10.1016/j.neurobiolaging.2020.02.024. Epub 2020 Mar 4.
Contingency awareness is thought to rely on an intact medial temporal lobe and also appears to be a function of age, as older subjects tend to be less aware. The current investigation used functional magnetic resonance imaging, transcranial direct current stimulation, and eyeblink classical conditioning to study brain processes related to contingency awareness as a function of age. Older adults were significantly less aware of the relationship between the tone-airpuff pairings than younger adults. Greater right parietal functional magnetic resonance imaging activation was associated with higher levels of contingency awareness for younger and older subjects. Cathodal transcranial direct current stimulation over the right parietal lobe led to lower levels of awareness in younger subjects without disrupting conditioned responses. Older adults exhibited hyperactivations in the parietal and medial temporal lobes, despite showing no conditioning deficits. These findings strongly support the idea that the parietal cortex serves as a substrate for contingency awareness and that age-related disruption of this region is sufficient to impair awareness, which may be a manifestation of some form of naturally occurring age-related neglect.
情境意识被认为依赖于完整的内侧颞叶，并且似乎也是年龄的功能，因为年龄较大的受试者往往不太有意识。当前的研究使用功能磁共振成像、经颅直流电刺激和眨眼经典条件反射来研究作为年龄函数的与情境意识相关的大脑过程。与年轻成年人相比，年长成年人对音调 - 空气脉冲配对之间的关系明显不太敏感。对于年轻和年长的受试者，更大的右顶叶功能磁共振成像激活与更高水平的情境意识相关。右顶叶的阴极经颅直流电刺激导致年轻受试者的意识水平降低，而不会破坏条件反应。尽管没有表现出条件反射缺陷，但老年受试者的顶叶和内侧颞叶表现出过度活跃。这些发现强烈支持顶叶皮层作为情境意识的基础的观点，并且与年龄相关的该区域的破坏足以损害意识，这可能是某种自然发生的与年龄相关的忽视的表现。
