Functions of delay-period activity in the prefrontal cortex and mnemonic scotomas revisited.
Functions of delay-period activity in the prefrontal cortex and mnemonic scotomas revisited.
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DOI：
10.3389/fnsys.2015.00002
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发表时间：
2015
影响因子：
3
通讯作者：
Funahashi S
中科院分区：
文献类型：
--
作者：
Funahashi S
工作记忆是理解前额叶功能的关键概念之一。延迟期活动是理解工作记忆在前额叶功能中的作用的重要神经关联。延迟期活动的重要性在于，这种活动不仅可以编码视觉空间信息，还可以编码各种信息，包括非空间视觉特征，听觉和触觉刺激，任务规则，预期奖励和数量。该活动还参与各种信息处理，包括感觉到运动的信息转换。延迟期活动的这些记忆特征使得能够执行前额叶皮层参与的各种重要操作，例如执行控制，因此，支持WM是理解前额叶功能的重要功能的概念。另一方面，虽然使用延迟反应任务的手动版本的实验已经揭示了许多重要的发现，该任务的视觉版本使我们能够使用多个线索位置，在延迟期间排除姿势定向，并进一步证明了前额叶皮层记忆功能的重要性。此外，单侧病变的猴子表现出特定的损害，只有在性能的记忆引导的眼跳直接对视觉线索的视野对侧的病变半球。这一结果表明，在每个半野的视觉空间坐标的记忆主要是在对侧前额叶皮层处理。这一结果进一步加强了前额叶皮层记忆功能的观点。因此，前额叶皮层和延迟期活动的记忆功能可能不需要重新考虑，但应该强调。
Working memory (WM) is one of key concepts to understand functions of the prefrontal cortex. Delay-period activity is an important neural correlate to understand the role of WM in prefrontal functions. The importance of delay-period activity is that this activity can encode not only visuospatial information but also a variety of information including non-spatial visual features, auditory and tactile stimuli, task rules, expected reward, and numerical quantity. This activity also participates in a variety of information processing including sensory-to-motor information transformation. These mnemonic features of delay-period activity enable to perform various important operations that the prefrontal cortex participates in, such as executive controls, and therefore, support the notion that WM is an important function to understand prefrontal functions. On the other hand, although experiments using manual versions of the delayed-response task had revealed many important findings, an oculomotor version of this task enabled us to use multiple cue positions, exclude postural orientation during the delay period, and further prove the importance of mnemonic functions of the prefrontal cortex. In addition, monkeys with unilateral lesions exhibited specific impairment only in the performance of memory-guided saccades directed toward visual cues in the visual field contralateral to the lesioned hemisphere. This result indicates that memories for visuospatial coordinates in each hemifield are processed primarily in the contralateral prefrontal cortex. This result further strengthened the idea of mnemonic functions of the prefrontal cortex. Thus, the mnemonic functions of the prefrontal cortex and delay-period activity may not need to be reconsidered, but should be emphasized.