Long-range inhibitory intersection of a retrosplenial thalamocortical circuit by apical tuft-targeting CA1 neurons
| Autor: | Jelena Radulovic, Laurie Lambot, Lynn Y. Ren, Gordon M. Shepherd, Xiaojian Li, Naoki Yamawaki |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Male Conditioning Classical Hippocampus Neural Inhibition Mice Transgenic Hippocampal formation Inhibitory postsynaptic potential Article 03 medical and health sciences 0302 clinical medicine Retrosplenial cortex Neural Pathways Animals Tuft Chromatin structure remodeling (RSC) complex GABAergic Neurons CA1 Region Hippocampal 030304 developmental biology Cerebral Cortex Neurons 0303 health sciences biology Chemistry General Neuroscience Subiculum Fear Synaptic Potentials Mice Inbred C57BL Electrophysiology 030104 developmental biology nervous system Anterior Thalamic Nuclei Synaptic plasticity Excitatory postsynaptic potential biology.protein GABAergic Female Neuroscience 030217 neurology & neurosurgery |
| Zdroj: | Nature neuroscience |
| ISSN: | 1546-1726 |
| Popis: | Dorsal hippocampus, retrosplenial cortex (RSC), and anterior thalamic nuclei (ATN) interact to mediate diverse cognitive functions, but the cellular basis for these interactions is unclear. We hypothesized a long-range circuit converging in layer 1 (L1) of RSC, based on the pathway anatomy of GABAergic CA1 retrosplenial-projecting (CA1-RP) neurons and thalamo-restrosplenial projections from ATN. We find that CA1→RSC projections stem from GABAergic neurons with a distinct morphology, electrophysiology, and molecular profile, likely corresponding to recently described Ntng1-expressing hippocampal interneurons. CA1-RP neurons monosynaptically inhibit L5 pyramidal neurons, principal outputs of RSC, via potent GABAergic synapses onto apical tuft dendrites in L1. These inhibitory inputs align precisely with L1-targeting thalamocortical excitatory inputs from ATN, particularly the anteroventral nucleus, forming a convergent circuit whereby CA1 inhibition can intercept ATN excitation to co-regulate RSC activity. Excitatory axons from subiculum, in contrast, innervate proximal dendrites in deeper layers. Short-term synaptic plasticity differs at each connection. Chemogenetically abrogating inhibitory CA1→RSC or excitatory ATN→RSC connections oppositely affects the encoding of contextual fear memory. Collectively, our findings identify multiple cellular mechanisms underlying hippocampo-thalamo-retrosplenial interactions, establishing CA1 RSC-projecting neurons as a distinct class with long-range axons that target apical tuft dendrites, and delineating an unusual cortical circuit in the RSC specialized for integrating long-range inhibition and thalamocortical excitation. |
| Databáze: | OpenAIRE |
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