Psychiatry, University of Minnesota, Minneapolis, Minnesota, USA.
Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA.
Eur J Neurosci. 2023 Mar;57(6):918-939. doi: 10.1111/ejn.15928. Epub 2023 Mar 3.
The computational role of a neuron during attention depends on its firing properties, neurotransmitter expression and functional connectivity. Neurons in the visual cortical area V4 are reliably engaged by selective attention but exhibit diversity in the effect of attention on firing rates and correlated variability. It remains unclear what specific neuronal properties shape these attention effects. In this study, we quantitatively characterised the distribution of attention modulation of firing rates across populations of V4 neurons. Neurons exhibited a continuum of time-varying attention effects. At one end of the continuum, neurons' spontaneous firing rates were slightly depressed with attention (compared to when unattended), whereas their stimulus responses were enhanced with attention. The other end of the continuum showed the converse pattern: attention depressed stimulus responses but increased spontaneous activity. We tested whether the particular pattern of time-varying attention effects that a neuron exhibited was related to the shape of their actions potentials (so-called 'fast-spiking' [FS] neurons have been linked to inhibition) and the strength of their coupling to the overall population. We found an interdependence among neural attention effects, neuron type and population coupling. In particular, we found neurons for which attention enhanced spontaneous activity but suppressed stimulus responses were less likely to be fast-spiking (more likely to be non-fast-spiking) and tended to have stronger population coupling, compared to neurons with other types of attention effects. These results add important information to our understanding of visual attention circuits at the cellular level.
在注意力过程中，神经元的计算作用取决于其发放特性、神经递质表达和功能连接。视觉皮层 V4 中的神经元被选择性注意可靠地激活，但在注意对发放率和相关变异性的影响方面表现出多样性。目前尚不清楚是什么特定的神经元特性塑造了这些注意效应。在这项研究中，我们定量地描述了 V4 神经元群体中发放率的注意调制的分布。神经元表现出连续的随时间变化的注意效应。在连续体的一端，神经元的自发发放率在注意力集中时（与未注意时相比）略有下降，而其对刺激的反应则增强。连续体的另一端则显示出相反的模式：注意力降低了对刺激的反应，但增加了自发活动。我们测试了一个神经元表现出的特定的时变注意效应模式是否与其动作电位的形状（所谓的“快速放电”[FS]神经元与抑制有关）以及与总体群体的耦合强度有关。我们发现，神经注意效应、神经元类型和群体耦合之间存在相互依存关系。特别是，我们发现那些注意力增加自发性活动但抑制刺激反应的神经元不太可能是快速放电（更可能是非快速放电），并且与具有其他类型注意效应的神经元相比，它们往往具有更强的群体耦合。这些结果为我们在细胞水平上理解视觉注意回路提供了重要信息。
