Tseng Hua-An, Han Xue
Biomedical Engineering Department, Boston University, Boston, MA, United States.
Front Physiol. 2021 Feb 11;12:618307. doi: 10.3389/fphys.2021.618307. eCollection 2021.
Prefrontal cortex (PFC) are broadly linked to various aspects of behavior. During sensory discrimination, PFC neurons can encode a range of task related information, including the identity of sensory stimuli and related behavioral outcome. However, it remains largely unclear how different neuron subtypes and local field potential (LFP) oscillation features in the mouse PFC are modulated during sensory discrimination. To understand how excitatory and inhibitory PFC neurons are selectively engaged during sensory discrimination and how their activity relates to LFP oscillations, we used tetrode recordings to probe well-isolated individual neurons, and LFP oscillations, in mice performing a three-choice auditory discrimination task. We found that a majority of PFC neurons, 78% of the 711 recorded individual neurons, exhibited sensory discrimination related responses that are context and task dependent. Using spike waveforms, we classified these responsive neurons into putative excitatory neurons with broad waveforms or putative inhibitory neurons with narrow waveforms, and found that both neuron subtypes were transiently modulated, with individual neurons' responses peaking throughout the entire duration of the trial. While the number of responsive excitatory neurons remain largely constant throughout the trial, an increasing fraction of inhibitory neurons were gradually recruited as the trial progressed. Further examination of the coherence between individual neurons and LFPs revealed that inhibitory neurons exhibit higher spike-field coherence with LFP oscillations than excitatory neurons during all aspects of the trial and across multiple frequency bands. Together, our results demonstrate that PFC excitatory neurons are continuously engaged during sensory discrimination, whereas PFC inhibitory neurons are increasingly recruited as the trial progresses and preferentially coordinated with LFP oscillations. These results demonstrate increasing involvement of inhibitory neurons in shaping the overall PFC dynamics toward the completion of the sensory discrimination task.
前额叶皮质（PFC）与行为的各个方面广泛相关。在感觉辨别过程中，PFC神经元可以编码一系列与任务相关的信息，包括感觉刺激的特性和相关的行为结果。然而，在感觉辨别过程中，小鼠PFC中不同的神经元亚型和局部场电位（LFP）振荡特征是如何被调节的，目前仍不清楚。为了了解兴奋性和抑制性PFC神经元在感觉辨别过程中是如何被选择性激活的，以及它们的活动与LFP振荡之间的关系，我们使用四极电极记录法来探测执行三选听觉辨别任务的小鼠中分离良好的单个神经元和LFP振荡。我们发现，大多数PFC神经元（711个记录的单个神经元中的78%）表现出与感觉辨别相关的反应，这些反应取决于背景和任务。利用尖峰波形，我们将这些反应性神经元分为具有宽波形的假定兴奋性神经元或具有窄波形的假定抑制性神经元，发现这两种神经元亚型都受到短暂调节，单个神经元的反应在整个试验过程中达到峰值。虽然反应性兴奋性神经元的数量在整个试验过程中基本保持不变，但随着试验的进行，越来越多的抑制性神经元被逐渐招募。对单个神经元与LFP之间的相干性进行进一步检查发现，在试验的各个阶段和多个频段中，抑制性神经元与LFP振荡的尖峰-场相干性均高于兴奋性神经元。总之，我们的结果表明，PFC兴奋性神经元在感觉辨别过程中持续被激活，而PFC抑制性神经元随着试验的进行被越来越多地招募，并优先与LFP振荡协调。这些结果表明，抑制性神经元在塑造PFC整体动态以完成感觉辨别任务中的作用越来越大。
