Correlated variability modifies working memory fidelity in primate prefrontal neuronal ensembles
Correlated variability modifies working memory fidelity in primate prefrontal neuronal ensembles
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DOI：
10.1073/pnas.1619949114
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发表时间：
2017-03-21
影响因子：
11.1
通讯作者：
Martinez-Trujillo, Julio C.
中科院分区：
文献类型：
--
作者：
Leavitt, Matthew L.;Pieper, Florian;Martinez-Trujillo, Julio C.
灵长类动物外侧前额叶皮层（LPFC）的神经元通过持续放电编码工作记忆（WM）表征，这种现象被假设是由相互连接的神经元集合内的循环动力学引起的。在这里，我们测试了这一假设，使用微电极阵列检查尖峰计数相关性（r（SC））在LPFC神经元合奏在空间WM任务。我们发现了一种模式的成对r（SC）在WM维护指示类似调谐的神经元之间的更强的耦合和不同调谐的神经元之间的抑制增加。然后我们使用线性解码器来量化高维rsc结构对神经元集合中信息编码的影响。我们发现，rsc结构可以促进或削弱编码，这取决于整体的大小和其组成神经元的调谐特性。一个简单的优化过程表明，接近最大的解码性能可以实现使用相对较少的神经元。这些WM优化的子系综更多的信号相关性（r（信号））-多样性和解剖学上的分散比预测的完整记录的人口的神经元的统计数据，他们往往包含的神经元，WM选择性差，但增强编码保真度塑造合奏的RSC结构。我们观察到的模式r（SC）LPFC神经元之间的经常性的动态表示WM相关的活动的机制，并r（SC）结构可以增加WM表示的保真度。因此，在LPFC神经元合奏WM编码产生于一个复杂的协同作用之间的单个神经元编码特性和多维，合奏级现象。
Neurons in the primate lateral prefrontal cortex (LPFC) encode working memory (WM) representations via sustained firing, a phenomenon hypothesized to arise from recurrent dynamics within ensembles of interconnected neurons. Here, we tested this hypothesis by using microelectrode arrays to examine spike count correlations (r(sc)) in LPFC neuronal ensembles during a spatial WM task. We found a pattern of pairwise r(sc) during WM maintenance indicative of stronger coupling between similarly tuned neurons and increased inhibition between dissimilarly tuned neurons. We then used a linear decoder to quantify the effects of the high-dimensional rsc structure on information coding in the neuronal ensembles. We found that the rsc structure could facilitate or impair coding, depending on the size of the ensemble and tuning properties of its constituent neurons. A simple optimization procedure demonstrated that near-maximum decoding performance could be achieved using a relatively small number of neurons. These WM-optimized subensembles were more signal correlation (r(signal))-diverse and anatomically dispersed than predicted by the statistics of the full recorded population of neurons, and they often contained neurons that were poorly WM-selective, yet enhanced coding fidelity by shaping the ensemble's rsc structure. We observed a pattern of r(sc) between LPFC neurons indicative of recurrent dynamics as a mechanism for WM-related activity and that the r(sc) structure can increase the fidelity of WM representations. Thus, WM coding in LPFC neuronal ensembles arises from a complex synergy between single neuron coding properties and multidimensional, ensemblelevel phenomena.