Lebedev Mikhail A, Messinger Adam, Kralik Jerald D, Wise Steven P
Laboratory of Systems Neuroscience, National Institute of Mental Health, Bethesda, Maryland, USA.
PLoS Biol. 2004 Nov;2(11):e365. doi: 10.1371/journal.pbio.0020365. Epub 2004 Oct 26.
A great deal of research on the prefrontal cortex (PF), especially in nonhuman primates, has focused on the theory that it functions predominantly in the maintenance of short-term memories, and neurophysiologists have often interpreted PF's delay-period activity in the context of this theory. Neuroimaging results, however, suggest that PF's function extends beyond the maintenance of memories to include aspects of attention, such as the monitoring and selection of information. To explore alternative interpretations of PF's delay-period activity, we investigated the discharge rates of single PF neurons as monkeys attended to a stimulus marking one location while remembering a different, unmarked location. Both locations served as potential targets of a saccadic eye movement. Although the task made intensive demands on short-term memory, the largest proportion of PF neurons represented attended locations, not remembered ones. The present findings show that short-term memory functions cannot account for all, or even most, delay-period activity in the part of PF explored. Instead, PF's delay-period activity probably contributes more to the process of attentional selection.
大量关于前额叶皮层（PF）的研究，尤其是在非人类灵长类动物中的研究，都集中在这样一种理论上，即它主要在短期记忆的维持中发挥作用，神经生理学家也经常在这一理论背景下解释PF的延迟期活动。然而，神经成像结果表明，PF的功能不仅限于记忆维持，还包括注意力的各个方面，如信息的监测和选择。为了探索对PF延迟期活动的其他解释，我们研究了猴子在记住一个未标记的不同位置时，关注标记一个位置的刺激时单个PF神经元的放电率。这两个位置都是眼球扫视运动的潜在目标。尽管该任务对短期记忆有很高要求，但PF神经元中最大比例代表的是被关注的位置，而非被记住的位置。目前的研究结果表明，短期记忆功能无法解释所研究的PF部分中所有甚至大部分的延迟期活动。相反，PF的延迟期活动可能对注意力选择过程贡献更大。
