Interspike Intervals Reveal Functionally Distinct Cell Populations in the Medial Entorhinal Cortex
Interspike Intervals Reveal Functionally Distinct Cell Populations in the Medial Entorhinal Cortex
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DOI：
10.1523/jneurosci.0276-15.2015
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发表时间：
2015-08-05
影响因子：
5.3
通讯作者：
Allen, Kevin
中科院分区：
文献类型：
--
作者：
Latuske, Patrick;Toader, Oana;Allen, Kevin
内侧内嗅皮层（MEC）的浅层含有空间选择性神经元，这些神经元对空间导航和记忆至关重要。这些高度特化的神经元包括网格细胞、边界细胞、头部方向细胞和不规则的空间选择细胞。此外，MEC神经元在毫秒时间尺度上的尖峰模式显示出很大的可变性。在这项研究中，我们分析了小鼠MEC表层神经元的尖峰序列，发现这些神经元可以根据其在125-250 Hz发射尖峰双峰的倾向分为两组。这两组被标记为“爆发性”和“非爆发性”神经元，其尖峰波形和尖峰间期适应不同，但显示出相似的平均放电率。在爆发型神经元中，网格细胞的空间周期性比非爆发型神经元更常见。相比之下，大多数具有头部方向选择性的神经元或那些在环境边缘放电的神经元是非爆发性神经元。在θ振荡期间，爆发性和非爆发性神经元都优先在周期的下降相结束附近放电，但爆发性神经元的尖峰放电发生在比非爆发性神经元更早的阶段。最后，同时记录的神经元之间的尖峰时间互相关的分析表明，这两个细胞类的差异耦合到快速尖峰interneurons：突发神经元的两倍可能有兴奋性的相互作用与假定的interneurons作为非突发神经元。这些结果表明，爆发性和非爆发性神经元差异整合在MEC网络，并优先编码不同的空间信号。
The superficial layers of the medial entorhinal cortex (MEC) contain spatially selective neurons that are crucial for spatial navigation and memory. These highly specialized neurons include grid cells, border cells, head-direction cells, and irregular spatially selective cells. In addition, MEC neurons display a large variability in their spike patterns at a millisecond time scale. In this study, we analyzed spike trains of neurons in the MEC superficial layers of mice and found that these neurons can be classified into two groups based on their propensity to fire spike doublets at 125-250 Hz. The two groups, labeled "bursty" and "non-bursty" neurons, differed in their spike waveforms and interspike interval adaptation but displayed a similar mean firing rate. Grid cell spatial periodicity was more commonly observed in bursty than in non-bursty neurons. In contrast, most neurons with head-direction selectivity or those that fired at the border of the environment were non-bursty neurons. During theta oscillations, both bursty and non-bursty neurons fired preferentially near the end of the descending phase of the cycle, but the spikes of bursty neurons occurred at an earlier phase than those of non-bursty neurons. Finally, analysis of spike-time crosscorrelations between simultaneously recorded neurons suggested that the two cell classes are differentially coupled to fast-spiking interneurons: bursty neurons were twice as likely to have excitatory interactions with putative interneurons as non-bursty neurons. These results demonstrate that bursty and non-bursty neurons are differentially integrated in the MEC network and preferentially encode distinct spatial signals.