Prefrontal cortex activity during the discrimination of relative distance.
Prefrontal cortex activity during the discrimination of relative distance.
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DOI：
10.1523/jneurosci.5373-10.2011
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发表时间：
2011-03-16
期刊：
影响因子：
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通讯作者：
Wise SP
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文献类型：
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作者：
Genovesio A;Tsujimoto S;Wise SP
为了与我们先前关于相对持续时间辨别的研究结果进行比较，我们研究了猴子执行相对距离辨别任务时的前额叶皮层活动。我们想知道前额叶皮层的相同部分是否会比较持续时间和距离，如果是的话，它们是否使用类似的机制。两个刺激依次出现在视频屏幕上，一个高于固定的参考点，另一个低于它不同的距离。经过一段时间的延迟，同样的两个刺激再次出现（作为选择刺激），猴子的任务是选择在最初呈现时出现在离参考点更远的地方的刺激。我们记录了背外侧前额叶皮层（46区）和尾侧前额叶皮层（8区）的神经元。虽然有些前额叶神经元编码刺激与参考点的绝对距离，但更多的前额叶神经元编码相对距离。范畴表征（“更远”），优于参数表征（“多远”）。相对距离编码通常是抽象的，对更远或更近的刺激进行相同程度的编码，与其在屏幕上的位置无关。在选择刺激出现之前的延迟期内，基于特征的编码取代了基于顺序的编码，而基于位置的编码-总是罕见的-下降到机会水平。目前的结果非常相似的持续时间歧视任务在相同的皮层区域。因此，我们的结论是，这些领域有助于基于空间和时间信息的决策。
To compare with our previous findings on relative-duration discrimination, we studied prefrontal cortex activity as monkeys performed a relative-distance discrimination task. We wanted to know whether the same parts of the prefrontal cortex compare durations and distances and, if so, whether they use similar mechanisms. Two stimuli appeared sequentially on a video screen, one above a fixed reference point, the other below it by a different distance. After a delay period, the same two stimuli reappeared (as choice stimuli), and the monkeys’ task was to choose the one that had appeared farther from the reference point during its initial presentation. We recorded from neurons in the dorsolateral prefrontal cortex (area 46) and the caudal prefrontal cortex (area 8). Although some prefrontal neurons encoded the absolute distance of a stimulus from the reference point, many more encoded relative distance. Categorical representations (‘farther’), predominated over parametric ones (‘how much farther’). Relative-distance coding was most often abstract, coding the farther or closer stimulus to the same degree, independent of its position on the screen. During the delay period before the choice stimuli appeared, feature-based coding supplanted order-based coding, and position-based coding—always rare—decreased to chance levels. The present results closely resembled those for a duration-discrimination task in the same cortical areas. We conclude, therefore, that these areas contribute to decisions based on both spatial and temporal information.