Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Vaud, Switzerland.
Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Vaud, Switzerland.
Cell Rep. 2020 Jun 9;31(10):107747. doi: 10.1016/j.celrep.2020.107747.
As we navigate in space, external landmarks and internal information guide our movement. Circuit and synaptic mechanisms that integrate these cues with head-direction (HD) signals remain, however, unclear. We identify an excitatory synaptic projection from the presubiculum (PreS) and the multisensory-associative retrosplenial cortex (RSC) to the anterodorsal thalamic reticular nucleus (TRN), so far classically implied in gating sensory information flow. In vitro, projections to TRN involve AMPA/NMDA-type glutamate receptors that initiate TRN cell burst discharge and feedforward inhibition of anterior thalamic nuclei. In vivo, chemogenetic anterodorsal TRN inhibition modulates PreS/RSC-induced anterior thalamic firing dynamics, broadens the tuning of thalamic HD cells, and leads to preferential use of allo- over egocentric search strategies in the Morris water maze. TRN-dependent thalamic inhibition is thus an integral part of limbic navigational circuits wherein it coordinates external sensory and internal HD signals to regulate the choice of search strategies during spatial navigation.
当我们在空间中导航时，外部地标和内部信息引导我们的运动。然而，将这些线索与头部方向 (HD) 信号整合的回路和突触机制尚不清楚。我们确定了从前下托 (PreS) 和多感觉关联的后穹窿皮质 (RSC) 到前背丘脑网状核 (TRN) 的兴奋性突触投射，迄今为止，该核被认为是门控感觉信息流的关键。在体外，TRN 的投射涉及 AMPA/NMDA 型谷氨酸受体，这些受体引发 TRN 细胞爆发放电和对前丘脑核的前馈抑制。在体内，化学遗传的前背 TRN 抑制调节 PreS/RSC 诱导的前丘脑放电动力学，拓宽丘脑 HD 细胞的调谐，并导致在 Morris 水迷宫中优先使用异体而非自我中心搜索策略。因此，TRN 依赖性丘脑抑制是边缘导航回路的一个组成部分，其中它协调外部感觉和内部 HD 信号，以调节空间导航期间搜索策略的选择。
