Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, 780 Bannatyne Avenue, Winnipeg, MB, R3E 0W2, Canada.
Departments of Psychiatry and Human Anatomy and Cell Sciences, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R3E 0W2, Canada.
Brain Struct Funct. 2022 Sep;227(7):2409-2437. doi: 10.1007/s00429-022-02534-6. Epub 2022 Jul 15.
The paraventricular nucleus of the thalamus (PVT) projects to areas of the forebrain involved in regulating behavior. Homeostatic challenges and salient cues activate the PVT and evidence shows that the PVT regulates appetitive and aversive responses. The brainstem is a source of afferents to the PVT and the present study was done to determine if the lateral parabrachial nucleus (LPB) is a relay for inputs to the PVT. Retrograde tracing experiments with cholera toxin B (CTB) demonstrate that the LPB contains more PVT projecting neurons than other regions of the brainstem including the catecholamine cell groups. The hypothesis that the LPB is a relay for signals to the PVT was assessed using an intersectional monosynaptic rabies tracing approach. Sources of inputs to LPB included the reticular formation; periaqueductal gray (PAG); nucleus cuneiformis; and superior and inferior colliculi. Distinctive clusters of input cells to LPB-PVT projecting neurons were also found in the dorsolateral bed nucleus of the stria terminalis (BSTDL) and the lateral central nucleus of the amygdala (CeL). Anterograde viral tracing demonstrates that LPB-PVT neurons densely innervate all regions of the PVT in addition to providing collateral innervation to the preoptic area, lateral hypothalamus, zona incerta and PAG but not the BSTDL and CeL. The paper discusses the anatomical evidence that suggests that the PVT is part of a network of interconnected neurons involved in arousal, homeostasis, and the regulation of behavioral states with forebrain regions potentially providing descending modulation or gating of signals relayed from the LPB to the PVT.
丘脑室旁核（PVT）投射到参与调节行为的前脑区域。体内平衡挑战和显著线索激活 PVT，有证据表明 PVT 调节食欲和厌恶反应。脑干是 PVT 的传入源，本研究旨在确定外侧臂旁核（LPB）是否是 PVT 传入的中继站。霍乱毒素 B（CTB）的逆行追踪实验表明，LPB 包含比脑干其他区域（包括儿茶酚胺细胞群）更多的 PVT 投射神经元。使用交叉单突触狂犬病毒追踪方法评估了 LPB 是 PVT 信号中继站的假设。LPB 的输入源包括网状结构、导水管周围灰质（PAG）、楔形核和上、下丘。还在终纹床核外侧部（BSTDL）和杏仁外侧中央核（CeL）中发现了 LPB-PVT 投射神经元输入细胞的独特簇。顺行病毒追踪表明，LPB-PVT 神经元除了对视前区、外侧下丘脑、未定带和 PAG 提供侧支支配外，还密集支配 PVT 的所有区域，而不支配 BSTDL 和 CeL。本文讨论了解剖学证据，表明 PVT 是参与觉醒、体内平衡和行为状态调节的相互连接神经元网络的一部分，前脑区域可能提供来自 LPB 到 PVT 的信号的下行调制或门控。
