Lellouche Yair, Minert Anne, Schreiber Caterin, Aroch Ilil, Vaso Kristina, Fishman Yelena, Devor Marshall
Department of Cell and Developmental Biology, Silberman Institute of Life Sciences, Jerusalem 9190401, Israel.
Department of Cell and Developmental Biology, Silberman Institute of Life Sciences, Jerusalem 9190401, Israel; The Center for Research on Pain, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
Neuroscience. 2020 Apr 15;432:188-204. doi: 10.1016/j.neuroscience.2020.02.022. Epub 2020 Feb 26.
The mesopontine tegmental anesthesia area (MPTA) is a small brainstem nucleus that, when exposed to minute quantities of GABA receptor agonists, induces a state of general anesthesia. In addition to immobility and analgesia this state is accompanied by widespread suppression of neural activity in the cerebral cortex and high delta-band power in the electroencephalogram. Collectively, MPTA neurons are known to project to a variety of forebrain targets which are known to relay to the cortex in a highly distributed manner. Here we ask whether ascending projections of individual MPTA neurons collateralize to several of these cortical relay nuclei, or access only one. Using rats, contrasting retrograde tracers were microinjected pairwise on one side into three ascending relays: the basal forebrain, the zona incerta-lateral hypothalamus and the intralaminar thalamic nuclear group. In addition, in separate animals, each target was microinjected bilaterally. MPTA neurons were then identified as being single-or double-labeled, indicating projection to one target nucleus or collateralization to both. Results indicated that double-labeling was rare, occurring on average in only 1.3% of the neurons sampled. The overwhelming majority of individual MPTA neurons showed specific connectivity, contributing to only one of the major ascending pathways, either ipsilaterally or contralaterally, but not bilaterally. This architecture would permit particular functional aspects of anesthetic loss-of-consciousness to be driven by specific subpopulations of MPTA neurons.
脑桥中脑被盖麻醉区（MPTA）是一个位于脑干的小核团，当暴露于微量的GABA受体激动剂时，会诱导全身麻醉状态。除了不动和镇痛外，这种状态还伴随着大脑皮层神经活动的广泛抑制以及脑电图中高δ波段功率。总的来说，已知MPTA神经元投射到多种前脑靶点，这些靶点以高度分散的方式中继到皮层。在这里，我们研究单个MPTA神经元的上行投射是侧支化到几个这些皮层中继核，还是仅连接到一个。我们使用大鼠，将对比逆行示踪剂成对微量注射到一侧的三个上行中继部位：基底前脑、未定带-外侧下丘脑和丘脑板内核群。此外，在单独的动物中，对每个靶点进行双侧微量注射。然后将MPTA神经元鉴定为单标记或双标记，分别表示投射到一个靶核或侧支化到两个靶核。结果表明，双标记很少见，平均仅在1.3%的采样神经元中出现。绝大多数单个MPTA神经元表现出特定的连接性，仅对主要上行通路之一有贡献，无论是同侧还是对侧，但不是双侧。这种结构将允许MPTA神经元的特定亚群驱动麻醉性意识丧失的特定功能方面。
