Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.
Center for Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China.
Front Neural Circuits. 2020 Feb 7;14:4. doi: 10.3389/fncir.2020.00004. eCollection 2020.
The piriform cortex (PC) is a key brain area involved in both processing and coding of olfactory information. It is implicated in various brain disorders, such as epilepsy, Alzheimer's disease, and autism. The PC consists of the anterior (APC) and posterior (PPC) parts, which are different anatomically and functionally. However, the direct input networks to specific neuronal populations within the APC and PPC remain poorly understood. Here, we mapped the whole-brain direct inputs to the two major neuronal populations, the excitatory glutamatergic principal neurons and inhibitory γ-aminobutyric acid (GABA)-ergic interneurons within the APC and PPC using the rabies virus (RV)-mediated retrograde trans-synaptic tracing system. We found that for both types of neurons, APC and PPC share some similarities in input networks, with dominant inputs originating from the olfactory region (OLF), followed by the cortical subplate (CTXsp), isocortex, cerebral nuclei (CNU), hippocampal formation (HPF) and interbrain (IB), whereas the midbrain (MB) and hindbrain (HB) were rarely labeled. However, APC and PPC also show distinct features in their input distribution patterns. For both types of neurons, the input proportion from the OLF to the APC was higher than that to the PPC; while the PPC received higher proportions of inputs from the HPF and CNU than the APC did. Overall, our results revealed the direct input networks of both excitatory and inhibitory neuronal populations of different PC subareas, providing a structural basis to analyze the diverse PC functions.
梨状皮层（PC）是参与嗅觉信息处理和编码的关键大脑区域。它与各种大脑疾病有关，如癫痫、阿尔茨海默病和自闭症。PC 由前（APC）和后（PPC）两部分组成，它们在解剖和功能上有所不同。然而，对于 APC 和 PPC 内特定神经元群体的直接输入网络仍知之甚少。在这里，我们使用狂犬病毒（RV）介导的逆行跨突触示踪系统，绘制了整个大脑对 APC 和 PPC 内两种主要神经元群体（兴奋性谷氨酸能主神经元和抑制性γ-氨基丁酸（GABA）能中间神经元）的直接输入。我们发现，对于这两种类型的神经元，APC 和 PPC 在输入网络方面具有一些相似之处，主要的输入源来自嗅觉区域（OLF），其次是皮质基板（CTXsp）、同型皮质、脑核（CNU）、海马结构（HPF）和间脑（IB），而中脑（MB）和后脑（HB）很少被标记。然而，APC 和 PPC 也在其输入分布模式上表现出明显的特征。对于这两种类型的神经元，来自 OLF 的输入比例到 APC 高于到 PPC；而 PPC 接收来自 HPF 和 CNU 的输入比例高于 APC。总的来说，我们的结果揭示了不同 PC 亚区的兴奋性和抑制性神经元群体的直接输入网络，为分析多样化的 PC 功能提供了结构基础。
