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Gao M, Noguchi A, Ikegaya Y. The subiculum sensitizes retrosplenial cortex layer 2/3 pyramidal neurons. J Physiol 2021; 599:3151-3167. [PMID: 33878801 DOI: 10.1113/jp281152] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 04/13/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Neurons in the retrosplenial cortex (RSC), a cerebral region that connects synaptically with various brain regions, are known to increase neuronal activity in accordance with hippocampal sharp wave-ripples. Pyramidal cells in granular RSC (gRSC) layer 2/3, but not layer 5, exhibit slowly ramping depolarization and considerably delayed spikes in response to a step-pulse current injection. The latencies of delayed spikes in RSC layer 2/3 pyramidal neurons were shortened by a preceding current injection. This effect was mimicked by activation of axonal afferents from the subiculum, but not of neocortical afferents. The subiculum is likely to facilitate information processing and flow in the RSC. ABSTRACT The retrosplenial cortex (RSC), a cerebral region involved in diverse cognitive functions, is an anatomical hub that forms monosynaptic connections with various brain areas. Here, we report a unique form of short-term intrinsic plasticity in mouse granular RSC layer 2/3 pyramidal cells. These cells exhibited delayed spikes in response to somatic current injection, but the spike latencies were shortened by a preceding brief depolarization (priming). This priming-induced sensitization is distinct from desensitization, which is commonly observed in other cortical neurons. The facilitatory priming effect lasted for more than 3 s, providing a time window for increased sensitivity to RSC inputs. Based on in vitro and in vivo patch-clamp recordings following optogenetic stimulation of axonal fibres, we found that preactivation of subicular afferents replicated the facilitatory priming effect. The results suggest that subicular inputs to RSC layer 2/3 neurons may modulate subsequent information integration in the RSC layer 2/3 circuits.
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Affiliation(s)
- Mengxuan Gao
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Asako Noguchi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Yuji Ikegaya
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan.,Institute of AI and Beyond, The University of Tokyo, Tokyo, 113-0033, Japan.,Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita City, Osaka, 565-0871, Japan
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Nixima K, Okanoya K, Ichinohe N, Kurotani T. Fast voltage-sensitive dye imaging of excitatory and inhibitory synaptic transmission in the rat granular retrosplenial cortex. J Neurophysiol 2017; 118:1784-1799. [PMID: 28701546 DOI: 10.1152/jn.00734.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 07/05/2017] [Accepted: 07/05/2017] [Indexed: 11/22/2022] Open
Abstract
Rodent granular retrosplenial cortex (GRS) has dense connections between the anterior thalamic nuclei (ATN) and hippocampal formation. GRS superficial pyramidal neurons exhibit distinctive late spiking (LS) firing property and form patchy clusters with prominent apical dendritic bundles. The aim of this study was to investigate spatiotemporal dynamics of signal transduction in the GRS induced by ATN afferent stimulation by using fast voltage-sensitive dye imaging in rat brain slices. In coronal slices, layer 1a stimulation, which presumably activated thalamic fibers, evoked propagation of excitatory synaptic signals from layers 2-4 to layers 5-6 in a direction perpendicular to the layer axis, followed by transverse signal propagation within each layer. In the presence of ionotropic glutamate receptor antagonists, inhibitory responses were observed in superficial layers, induced by direct activation of inhibitory interneurons in layer 1. In horizontal slices, excitatory signals in deep layers propagated transversely mainly from posterior to anterior via superficial layers. Cortical inhibitory responses upon layer 1a stimulation in horizontal slices were weaker than those in the coronal slices. Observed differences between coronal and horizontal planes suggest anisotropy of the intracortical circuitry. In conclusion, ATN inputs are processed differently in coronal and horizontal planes of the GRS and then conveyed to other cortical areas. In both planes, GRS superficial layers play an important role in signal propagation, which suggests that superficial neuronal cascade is crucial in the integration of multiple information sources.NEW & NOTEWORTHY Superficial neurons in the rat granular retrosplenial cortex (GRS) show distinctive late-spiking (LS) firing property. However, little is known about spatiotemporal dynamics of signal transduction in the GRS. We demonstrated LS neuron network relaying thalamic inputs to deep layers and anisotropic distribution of inhibition between coronal and horizontal planes. Since deep layers of the GRS receive inputs from the subiculum, GRS circuits may work as an integrator of multiple sources such as sensory and memory information.
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Affiliation(s)
- Ken'ichi Nixima
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo, Japan.,ERATO Okanoya Emotional Information Project, Japan Science and Technology Agency, Hirosawa, Wako, Saitama, Japan.,Emotional Information Joint Research Laboratory, RIKEN Brain Science Institute, Hirosawa, Wako, Saitama, Japan; and
| | - Kazuo Okanoya
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo, Japan.,ERATO Okanoya Emotional Information Project, Japan Science and Technology Agency, Hirosawa, Wako, Saitama, Japan.,Emotional Information Joint Research Laboratory, RIKEN Brain Science Institute, Hirosawa, Wako, Saitama, Japan; and
| | - Noritaka Ichinohe
- Molecular Analysis of Higher Brain Function (Ichinohe group), RIKEN Brain Science Institute, Hirosawa, Wako, Saitama, Japan
| | - Tohru Kurotani
- ERATO Okanoya Emotional Information Project, Japan Science and Technology Agency, Hirosawa, Wako, Saitama, Japan; .,Emotional Information Joint Research Laboratory, RIKEN Brain Science Institute, Hirosawa, Wako, Saitama, Japan; and.,Molecular Analysis of Higher Brain Function (Ichinohe group), RIKEN Brain Science Institute, Hirosawa, Wako, Saitama, Japan
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Kádár E, Vico-Varela E, Aldavert-Vera L, Huguet G, Morgado-Bernal I, Segura-Torres P. Increase in c-Fos and Arc protein in retrosplenial cortex after memory-improving lateral hypothalamic electrical stimulation treatment. Neurobiol Learn Mem 2016; 128:117-24. [DOI: 10.1016/j.nlm.2015.12.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 12/21/2015] [Accepted: 12/30/2015] [Indexed: 12/19/2022]
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Okanoya K. Learning, epigenetics, and computation: an extension on Fitch's proposal. Comment on "Toward a computational framework for cognitive biology: unifying approaches from cognitive neuroscience and comparative cognition" by W. Tecumseh Fitch. Phys Life Rev 2014; 11:389-90. [PMID: 25027505 DOI: 10.1016/j.plrev.2014.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 07/03/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Kazuo Okanoya
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
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