Center for Neuroscience, University of California at Davis, Davis, California 95616, USA.
J Neurosci. 2010 Nov 3;30(44):14795-804. doi: 10.1523/JNEUROSCI.3393-10.2010.
The compromised abilities to localize sounds and to understand speech are two hallmark deficits in aged individuals. The auditory cortex is necessary for these processes, yet we know little about how normal aging affects these early cortical fields. In this study, we recorded the spatial tuning of single neurons in primary (auditory cortex, A1) and secondary (caudolateral field, CL) auditory cortical areas in young and aged alert rhesus macaques. We found that the neurons of aged animals had greater spontaneous and driven activity, and broader spatial tuning compared with those of younger animals. Importantly, spatial tuning was not sharpened between A1 and CL in aged monkeys as it is in younger monkeys. This implies that a major effect of normal aging is a degradation of the hierarchical processing between serially connected cortical areas, which could be a key contributing mechanism of the general cognitive decline that is commonly observed in normal aging.
定位声音和理解言语的能力受损是老年人的两个显著缺陷。听觉皮层对于这些过程是必要的，但我们对正常衰老如何影响这些早期皮层区域知之甚少。在这项研究中，我们记录了年轻和老年警觉恒河猴初级（听觉皮层，A1）和次级（外侧场，CL）听觉皮层区域中单个神经元的空间调谐。我们发现，与年轻动物相比，老年动物的神经元具有更高的自发和驱动活动，以及更广泛的空间调谐。重要的是，与年轻猴子相比，老年猴子的 A1 和 CL 之间的空间调谐并没有变尖锐。这意味着正常衰老的一个主要影响是串联连接的皮层区域之间的分层处理退化，这可能是正常衰老中普遍观察到的一般认知能力下降的关键促成机制。
