Discharge-Rate Persistence of Baseline Activity During Fixation Reflects Maintenance of Memory-Period Activity in the Macaque Posterior Parietal Cortex
Discharge-Rate Persistence of Baseline Activity During Fixation Reflects Maintenance of Memory-Period Activity in the Macaque Posterior Parietal Cortex
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DOI：
10.1093/cercor/bht031
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发表时间：
2014-06-01
期刊：
影响因子：
3.7
通讯作者：
Ogawa, Tadashi
中科院分区：
文献类型：
--
作者：
Nishida, Satoshi;Tanaka, Tomohiro;Ogawa, Tadashi
最近的证据表明，自发活动的时空模式反映了感官刺激诱发的活动模式。然而，很少有研究探讨是否反应轮廓的任务诱发活动，这是不相关的外部感官刺激，而是内部的过程，也反映在那些自发活动。为了解决这个问题，我们记录了猴子进行反应时间和延迟反应视觉搜索任务时外侧顶内区（LIP）神经元的活动。我们特别关注延迟反应任务中延迟期活动的目标位置依赖性调制（延迟期调制），以及反应时间任务中固定期活动（基线活动维持）的放电率持续性。通过2个单独箱的峰计数之间的相关性评估基线活性维持。我们发现，基线活动的维持，计算由一个很长的时间间隔分开的箱子，（200-500 ms）与延迟期调制相关，而从由短间隔分隔的bin计算的延迟期调制与延迟期调制相关。（类似于100 ms）与基线活动的试验间波动相关，这表明延迟期活动中保持任务相关信息的能力与基线活动维持程度之间存在时间尺度依赖性联系。
Recent evidence has demonstrated that spatiotemporal patterns of spontaneous activity reflect the patterns of activity evoked by sensory stimuli. However, few studies have examined whether response profiles of task-evoked activity, which is not related to external sensory stimuli but rather to internal processes, are also reflected in those of spontaneous activity. To address this, we recorded activity of neurons in the lateral intraparietal area (LIP) when monkeys performed reaction-time and delayed-response visual-search tasks. We particularly focused on the target location-dependent modulation of delay-period activity (delay-period modulation) in the delayed-response task, and the discharge-rate persistency in fixation-period activity (baseline-activity maintenance) in the reaction-time task. Baseline-activity maintenance was assessed by the correlation between the spike counts of 2 separate bins. We found that baseline-activity maintenance, calculated from bins separated by a long interval (200-500 ms), was correlated with delay-period modulation, whereas that calculated from bins separated by a short interval (similar to 100 ms) was correlated with trial-to-trial fluctuations in baseline activity, suggesting a link between the capability to hold task-related information in delay-period activity and the degree of baseline-activity maintenance in a timescale-dependent manner.