Effects of aging on value-directed modulation of semantic network activity during verbal learning.
Effects of aging on value-directed modulation of semantic network activity during verbal learning.
复制标题
DOI：
10.1016/j.neuroimage.2015.07.079
复制
发表时间：
2016-01-15
期刊：
影响因子：
5.7
通讯作者：
Knowlton BJ
中科院分区：
文献类型：
--
作者：
Cohen MS;Rissman J;Suthana NA;Castel AD;Knowlton BJ
随着年龄的增长，记忆回忆的损伤是很明显的，但老年人有选择性地记住被认为有价值的信息的能力却得到了显著的保留。在这里，我们使用功能磁共振成像来比较健康的老年人和年轻人在编码高值词和低值词时的大脑活动，以确定老年人实现价值导向记忆选择性的方式是否存在差异。我们发现，老年人的记忆选择性与单词呈现过程中左半球涉及语义处理的区域激活的价值相关变化有关，这与年轻人相似。然而，高选择性的年轻人在编码高价值项目时语义网络活动相对增加，而高选择性的老年人在编码低价值项目时语义网络活动相对减少。此外，只有年轻人在每个要记住的单词之前呈现价值线索时，语义和奖励处理区域的活动表现出与价值相关的增加。因此，年轻人对线索价值的反应比老年人更积极，但线索期大脑活动中价值相关差异的大小并不能预测记忆选择性的个体差异。因此，我们的数据也表明，与年龄相关的刺激前活动减少并不总是导致低效的表现。
While impairments in memory recall are apparent in aging, older adults show a remarkably preserved ability to selectively remember information deemed valuable. Here, we use fMRI to compare brain activation in healthy older and younger adults during encoding of high and low value words to determine whether there are differences in how older adults achieve value-directed memory selectivity. We find that memory selectivity in older adults is associated with value-related changes in activation during word presentation in left hemisphere regions that are involved in semantic processing, similar to young adults. However, highly selective young adults show a relatively greater increase in semantic network activity during encoding of high-value items, whereas highly selective older adults show relatively diminished activity during encoding of low-value items. Additionally, only younger adults showed value-related increases in activity in semantic and reward processing regions during presentation of the value cue preceding each to-be-remembered word. Young adults therefore respond to cue value more proactively than do older adults, yet the magnitude of value-related differences in cue period brain activity did not predict individual differences in memory selectivity. Thus, our data also show that age-related reductions in prestimulus activity do not always lead to inefficient performance.