Common rules guide comparisons of speed and direction of motion in the dorsolateral prefrontal cortex.
Common rules guide comparisons of speed and direction of motion in the dorsolateral prefrontal cortex.
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DOI：
10.1523/jneurosci.4075-12.2013
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发表时间：
2013-01-16
期刊：
影响因子：
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通讯作者：
Pasternak T
中科院分区：
文献类型：
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作者：
Hussar CR;Pasternak T
当猴子需要判断一个刺激的运动方向是否与工作记忆中另一个刺激的运动方向相同或不同时，背外侧前额叶皮质(DLPFC)的神经元忠实地代表被评估的运动方向，并有助于它们的比较。在这里，我们研究了DLPFC神经元是否更普遍地参与了其他类型的感觉比较。这种参与将支持DLPFC内普遍的感觉比较机制的存在，揭示该区域在比较任务期间可能向上游感觉神经元提供的自上而下的影响。当猴子执行记忆引导的决策任务时，我们记录了DLPFC中单个神经元的活动，其中重要的维度是两个顺序呈现的移动随机点刺激的速度。我们发现，许多神经元，无论是窄峰推测的局部中间神经元，还是宽峰推测的锥体输出细胞，都是速度选择性的，其调谐让人想起在运动处理中颞叶(MT)皮质区观察到的。在整个延迟过程中，宽峰神经元更加活跃，表现出预期性的频率调制和瞬时的速度选择性周期。在比较刺激期间，两种细胞类型的反应都受到第一个刺激的速度的调节，它们的活动对动物的行为报告具有很高的预测性。这些结果与运动方向比较的结果相似，表明在DLPFC中存在普遍的神经机制，为感觉信号的比较服务。
When a monkey needs to decide whether motion direction of one stimulus is the same or different as that of another held in working memory, neurons in dorsolateral prefrontal cortex (DLPFC) faithfully represent the motion directions being evaluated and contribute to their comparison. Here, we examined whether DLPFC neurons are more generally involved in other types of sensory comparisons. Such involvement would support the existence of generalized sensory comparison mechanisms within DLPFC, shedding light on top-down influences this region is likely to provide to the upstream sensory neurons during comparison tasks. We recorded activity of individual neurons in the DLPFC while monkeys performed a memory-guided decision task in which the important dimension was the speed of two sequentially presented moving random-dot stimuli. We found that many neurons, both narrow-spiking putative local interneurons and broad-spiking putative pyramidal output cells, were speed-selective, with tuning reminiscent of that observed in the motion processing middle temporal (MT) cortical area. Throughout the delay, broad-spiking neurons were more active, showing anticipatory rate modulation and transient periods of speed selectivity. During the comparison stimulus, responses of both cell types were modulated by the speed of the first stimulus, and their activity was highly predictive of the animals’ behavioral report. These results are similar to those found for comparisons of motion direction, suggesting the existence of generalized neural mechanisms in the DLPFC subserving the comparison of sensory signals.