Analysis of extracellular spike waveforms and associated receptive fields of neurons in cat primary visual cortex
Analysis of extracellular spike waveforms and associated receptive fields of neurons in cat primary visual cortex
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DOI：
10.1113/jp280844
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发表时间：
2021-03-02
影响因子：
5.5
通讯作者：
Meffin, Hamish
中科院分区：
文献类型：
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作者：
Sun, Shi H.;Almasi, Ali;Meffin, Hamish
在视觉皮层（17/18区，V1）记录的细胞尖峰通常分为常规尖峰（RS）和快速尖峰（FS）。利用多电极阵列定位于cat V1和宽带刺激，我们发现还存在一类独特的正尖峰（PS）波形，PS单元主要与非定向感受野相关，而RS和FS单元具有定向选择性感受野。我们认为PS单位是源自丘脑的轴突的记录。我们的研究结果进一步证实了这一结论，即我们可以记录皮层沉默后的PS单元，但不能记录RS和FS单元。我们发现的重要性在于，我们能够使用多电极细胞外记录技术高精度地将spike形状与感受野特征联系起来。这使得可以从未来的皮层实验中提取的信息量大大增加。从视觉皮层记录的细胞外尖峰波形被分为常规尖峰（RS）和快速尖峰（FS）单元。虽然这两种类型的尖峰波形都是负优势的，但我们发现在麻醉猫的视觉区17/18 （V1）也有不同类型的尖峰波形，具有正优势的波形，这并不经常被报道。分析了不同类型的脉冲波形的空间感受野（RFs），客观地揭示了定向和非定向空间感受野的存在。我们发现，与文献中来自轴突的记录相关的具有正优势尖峰的单位，大多数是非定向rf(84%)，这与在背侧膝状核（dLGN）中观察到的中心-环绕rf相似。因此，我们假设这些正主导波形可能是dLGN事件的记录。我们记录了使用muscimol（一种皮质消音器）前后V1的情况，发现阳性优势尖峰（PS）仍然存在，而RS和FS细胞则没有。我们还注意到，PS单元具有通常与dLGN单元相关的峰值特征（即更高的响应峰值率，更低的响应延迟和更高的突发峰值比例）。我们的研究结果定量地表明，有可能将皮层神经元的射频特性与特定的峰值波形相关联。这意味着细胞外记录应该如何解释，并且现在可以考虑复杂的实验，这在以前是非常具有挑战性的，例如评估皮质组织同一位置的大脑区域之间的前馈连接。
Key pointsExtracellular spikes recorded in the visual cortex (Area 17/18, V1) are commonly classified into either regular-spiking (RS) or fast-spiking (FS).Using multi-electrode arrays positioned in cat V1 and a broadband stimulus, we show that there is also a distinct class with positive-spiking (PS) waveforms.PS units were associated mainly with non-oriented receptive fields while RS and FS units had orientation-selective receptive fields.We suggest that PS units are recordings of axons originating from the thalamus. This conclusion was reinforced by our finding that we could record PS units after cortical silencing, but not record RS and FS units.The importance of our findings is that we were able to correlate spike shapes with receptive field characteristics with high precision using multi-electrode extracellular recording techniques. This allows considerable increases in the amount of information that can be extracted from future cortical experiments.Extracellular spike waveforms from recordings in the visual cortex have been classified into either regular-spiking (RS) or fast-spiking (FS) units. While both these types of spike waveforms are negative-dominant, we show that there are also distinct classes of spike waveforms in visual Area 17/18 (V1) of anaesthetised cats with positive-dominant waveforms, which are not regularly reported.The spatial receptive fields (RFs) of these different spike waveform types were estimated, which objectively revealed the existence of oriented and non-oriented RFs. We found that units with positive-dominant spikes, which have been associated with recordings from axons in the literature, had mostly non-oriented RFs (84%), which are similar to the centre-surround RFs observed in the dorsal lateral geniculate nucleus (dLGN). Thus, we hypothesise that these positive-dominant waveforms may be recordings from dLGN afferents. We recorded from V1 before and after the application of muscimol (a cortical silencer) and found that the positive-dominant spikes (PS) remained while the RS and FS cells did not. We also noted that the PS units had spiking characteristics normally associated with dLGN units (i.e. higher response spike rates, lower response latencies and higher proportion of burst spikes). Our findings show quantitatively that it is possible to correlate the RF properties of cortical neurons with particular spike waveforms. This has implications for how extracellular recordings should be interpreted and complex experiments can now be contemplated that would have been very challenging previously, such as assessing the feedforward connectivity between brain areas in the same location of cortical tissue.