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Synchronous circadian voltage rhythms with asynchronous calcium rhythms in the suprachiasmatic nucleus. Proc Natl Acad Sci U S A 2017; 114:E2476-E2485. [PMID: 28270612 DOI: 10.1073/pnas.1616815114] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The suprachiasmatic nucleus (SCN), the master circadian clock, contains a network composed of multiple types of neurons which are thought to form a hierarchical and multioscillator system. The molecular clock machinery in SCN neurons drives membrane excitability and sends time cue signals to various brain regions and peripheral organs. However, how and at what time of the day these neurons transmit output signals remain largely unknown. Here, we successfully visualized circadian voltage rhythms optically for many days using a genetically encoded voltage sensor, ArcLightD. Unexpectedly, the voltage rhythms are synchronized across the entire SCN network of cultured slices, whereas simultaneously recorded Ca2+ rhythms are topologically specific to the dorsal and ventral regions. We further found that the temporal order of these two rhythms is cell-type specific: The Ca2+ rhythms phase-lead the voltage rhythms in AVP neurons but Ca2+ and voltage rhythms are nearly in phase in VIP neurons. We confirmed that circadian firing rhythms are also synchronous and are coupled with the voltage rhythms. These results indicate that SCN networks with asynchronous Ca2+ rhythms produce coherent voltage rhythms.
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Longordo F, To MS, Ikeda K, Stuart GJ. Sublinear integration underlies binocular processing in primary visual cortex. Nat Neurosci 2013; 16:714-23. [PMID: 23644484 DOI: 10.1038/nn.3394] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 04/08/2013] [Indexed: 12/12/2022]
Abstract
Although we know much about the capacity of neurons to integrate synaptic inputs in vitro, less is known about synaptic integration in vivo. Here we address this issue by investigating the integration of inputs from the two eyes in mouse primary visual cortex. We find that binocular inputs to layer 2/3 pyramidal neurons are integrated sublinearly in an amplitude-dependent manner. Sublinear integration was greatest when binocular responses were largest, as occurs at the preferred orientation and binocular disparity, and highest contrast. Using voltage-clamp experiments and modeling, we show that sublinear integration occurs postsynaptically. The extent of sublinear integration cannot be accounted for solely by nonlinear integration of excitatory inputs, even when they are activated closely in space and time, but requires balanced recruitment of inhibition. Finally, we show that sublinear binocular integration acts as a divisive form of gain control, linearizing the output of binocular neurons and enhancing orientation selectivity.
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Affiliation(s)
- Fabio Longordo
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia.
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Wei B, Kumada T, Furukawa T, Inoue K, Watanabe M, Sato K, Fukuda A. Pre- and post-synaptic switches of GABA actions associated with Cl- homeostatic changes are induced in the spinal nucleus of the trigeminal nerve in a rat model of trigeminal neuropathic pain. Neuroscience 2012; 228:334-48. [PMID: 23103796 DOI: 10.1016/j.neuroscience.2012.10.043] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/16/2012] [Accepted: 10/19/2012] [Indexed: 02/01/2023]
Abstract
Although trigeminal neuropathic pain is one of the most common chronic pain syndromes, the etiology is still unknown. Here, a rat model was generated using chronic constrictive injury (CCI) with ligation of the infraorbital nerve to test the hypothesis that collapse of chloride homeostasis in trigeminal neurons causes impairment of γ-aminobutyric acid-ergic (GABAergic) inhibition and induces trigeminal allodynia. Rats showed a reduction and increase in pain threshold and pain response scores, respectively, to mechanical stimulation, 1 and 3weeks after CCI. In situ hybridization and immunohistochemical analysis showed that inward-directed Na(+), K(+)-2Cl(-) cotransporter (NKCC1) mRNA and protein were upregulated in the small-sized and large-sized primary neurons in the injured side of the trigeminal ganglion and in the peripherin-positive terminal, respectively, for the first 2weeks, while outward-directed K(+)-Cl(-) cotransporter (KCC2) mRNA and protein were downregulated in secondary relay neurons on the injured side of the spinal trigeminal nucleus caudalis (Sp5C). Optical imaging of evoked synaptic responses using a voltage-sensitive dye revealed that pre- and post-synaptic GABA actions were disinhibited and excitatory in the injured side, respectively, but inhibited in the sham-operated side of the Sp5C. This downregulation of KCC2 in the Sp5C may result in an excitatory switch by impairing postsynaptic GABA inhibition. GABA-mediated presynaptic disinhibition was attenuated by bumetanide, suggesting that NKCC1 upregulation in primary neurons may facilitate pain transmission by presynaptic GABAergic depolarization. Such Cl(-) homeostatic disruption resulting in perturbation of the inhibitory system possibly increases pain transmission, which may underlie the pathophysiology of trigeminal neuropathic pain.
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Affiliation(s)
- B Wei
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
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McQuiston AR. Mu opioid receptor activation normalizes temporo-ammonic pathway driven inhibition in hippocampal CA1. Neuropharmacology 2010; 60:472-9. [PMID: 21056047 DOI: 10.1016/j.neuropharm.2010.10.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 10/26/2010] [Accepted: 10/29/2010] [Indexed: 11/24/2022]
Abstract
The hippocampus of the mammalian brain is important for the formation of long-term memories. Hippocampal-dependent learning can be affected by a number of neurotransmitters including the activation of μ-opioid receptors (MOR). It has been shown that MOR activation can alter synaptic plasticity and network oscillations in the hippocampus, both of which are thought to be important for the encoding of information and formation of memories. One hippocampal oscillation that has been correlated with learning and memory formation is the 4-10 Hz theta rhythm. During theta rhythms, inputs to hippocampal CA1 from CA3 (Schaffer collaterals, SC) and the entorhinal cortex (perforant path) can integrate at different times within an individual theta cycle. Consequently, when excitatory inputs in the stratum lacunosum-moleculare (the temporo-ammonic pathway (TA), which includes the perforant path) are stimulated approximately one theta period before SC inputs, the TA can indirectly inhibit SC inputs. This inhibition is due to the activation of postsynaptic GABA(B) receptors on CA1 pyramidal neurons. Importantly, MOR activation has been shown to suppress GABA(B) inhibitory postsynaptic potentials in CA1 pyramidal neurons. Therefore, we examined how MOR activation affects the integration between TA inputs and SC inputs in hippocampal CA1. To do this we used voltage-sensitive dye imaging and whole cell patch clamping from acute hippocampal slices taken from young adult rats. Here we show that MOR activation has no effect on the integration between TA and SC inputs when activation of the TA precedes SC by less than one half of a theta cycle (<75 ms). However, MOR activation completely blocked the inhibitory action of TA on SC inputs when TA stimulation occurred approximately one theta cycle before SC activation (>150 ms). This MOR suppression of TA driven inhibition occurred in both the SC input layer of hippocampal CA1 (stratum radiatum) and the output layer of CA1 pyramidal neurons (stratum pyramidale). Thus MOR activation can have profound effects on the temporal integration between two primary excitatory pathways to hippocampal CA1 and subsequently the resultant output from CA1 pyramidal neurons. These data provide important information for understanding how acute or chronic MOR activation may affect the integration of activity within hippocampal CA1 during theta rhythm.
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Affiliation(s)
- A Rory McQuiston
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Box 980709, Richmond, VA 23298, USA.
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McQuiston AR. Cholinergic modulation of excitatory synaptic input integration in hippocampal CA1. J Physiol 2010; 588:3727-42. [PMID: 20693290 DOI: 10.1113/jphysiol.2010.188581] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
During theta rhythm, the timing of inputs to hippocampal CA1 from the perforant path (PP) of the entorhinal cortex and the Schaffer collaterals (SCs) from individual CA3 pyramidal neurons can vary within an individual theta period. Importantly, during theta rhythms these interactions occur during elevated acetylcholine concentrations. Thus, I examined the effect that PP inputs have on SC inputs in hippocampal CA1 during cholinergic receptor activation. To do this I measured the impact that a single electrical stimulus of the stratum lacunosum-moleculare (SLM, which contains the PP) had on excitation evoked by stimulation of the stratum radiatum (SR, which contains the SC) using voltage-sensitive dye imaging, field excitatory postsynaptic potentials and whole cell patch clamping in rat hippocampal brain slices. My data showed that SLM stimulation one half a theta cycle or less (25-75 ms) before SR stimulation resulted in the summation of excitatory events in SR and SP of hippocampal CA1. The summation was unaffected by cholinergic receptor activation by carbachol. SLM stimulation one theta cycle (150-225 ms) preceding SR stimulation significantly suppressed excitatory events measured in SR and SP. This SLM stimulus inhibition of SR-driven excitatory events was augmented by carbachol application. The carbachol effect was blocked by atropine and SLM-driven suppression of excitatory events was blocked by the GABA(B) receptor antagonist CGP 54626. SR field EPSP slopes were unaffected by SLM prepulses. Carbachol increased the probability of SR input to drive action potential firing in CA1 pyramidal neurons, which was inhibited by SLM prepulses (150-225 ms). Together these data provide important information regarding the integration of inputs in hippocampal CA1 during theta rhythms. More specifically, SR inputs can be differentially gated by SLM feedforward inhibition at varying temporal intervals within a theta cycle.
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Affiliation(s)
- A Rory McQuiston
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA.
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Kang J, Wu J, Smerieri A, Feng J. Weber's law implies neural discharge more regular than a Poisson process. Eur J Neurosci 2010; 31:1006-18. [PMID: 20377615 DOI: 10.1111/j.1460-9568.2010.07145.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Weber's law is one of the basic laws in psychophysics, but the link between this psychophysical behavior and the neuronal response has not yet been established. In this paper, we carried out an analysis on the spike train statistics when Weber's law holds, and found that the efferent spike train of a single neuron is less variable than a Poisson process. For population neurons, Weber's law is satisfied only when the population size is small (< 10 neurons). However, if the population neurons share a weak correlation in their discharges and individual neuronal spike train is more regular than a Poisson process, Weber's law is true without any restriction on the population size. Biased competition attractor network also demonstrates that the coefficient of variation of interspike interval in the winning pool should be less than one for the validity of Weber's law. Our work links Weber's law with neural firing property quantitatively, shedding light on the relation between psychophysical behavior and neuronal responses.
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Affiliation(s)
- Jing Kang
- Department of Computer Science, University of Warwick, Coventry CV4 7AL, UK
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Cappaert NLM, Wadman WJ, Witter MP. Spatiotemporal analyses of interactions between entorhinal and CA1 projections to the subiculum in rat brain slices. Hippocampus 2008; 17:909-21. [PMID: 17559098 DOI: 10.1002/hipo.20309] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The subiculum and the entorhinal cortex (EC) are important structures in processing and transmitting information between the neocortex and the hippocampus. The subiculum potentially receives information from the EC through two routes. In addition to a direct projection from EC to the subiculum, there is an indirect polysynaptic connection. The latter uses a number of possible pathways, which all converge onto the final projection from the hippocampal field CA1 to the subiculum. In this series of experiments we investigated to what extent activity in both pathways influences population activity of subicular neurons. We used voltage sensitive dyes in combined hippocampal-EC slices of the rat to measure the spatio-temporal activity patterns. To activate the two inputs to the subiculum, stimulation electrodes were placed in the stratum oriens/alveus of CA1 and in layer III of the medial EC. The response patterns evoked in the subiculum after electrical stimulation of each of these input pathways separately were compared with the response patterns after simultaneous stimulation of both areas (medial EC + CA1). A comparison of the computed added responses of the two individual stimulations with the measured responses after simultaneous stimulation suggests that both inputs are linearly added in the subiculum with very little nonlinear interactions. This strongly suggests that in the subiculum interaction at a single cell level of the direct and the indirect pathways from the EC is an unlikely scenario.
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Affiliation(s)
- Natalie L M Cappaert
- Department of Anatomy, Institute for Clinical and Experimental Neurosciences, VU University Medical Center, Amsterdam, The Netherlands.
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Andras P. A model for emergent complex order in small neural networks. J Integr Neurosci 2004; 2:55-69. [PMID: 15011277 DOI: 10.1142/s0219635203000172] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2003] [Revised: 04/15/2003] [Indexed: 11/18/2022] Open
Abstract
A new neural network model is introduced in this paper. The aim of the proposed Sierpinski neural networks is to provide a simple and biologically plausible neural network architecture that produces emergent complex spatio-temporal patterns through the activity of the output neurons of the network and is able to perform computational tasks. Such networks may play an important role in the analysis and understanding of complex dynamic activity observed at various levels of biological neural systems. The proposed Sierpinski neural networks are described in detail and their functioning is analyzed. We discuss about emerging neural activity patterns and their interpretations, neuro-computation with such emerging activity patterns, and also possible implications for computational neuroscience.
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Affiliation(s)
- Peter Andras
- Claremont Tower, School of Computing Science, University of Newcastle, Newcastle upon Tyne, NE1 7RU, UK.
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Kawamura Y, Manita S, Nakamura T, Inoue M, Kudo Y, Miyakawa H. Glutamate release increases during mossy-CA3 LTP but not during Schaffer-CA1 LTP. Eur J Neurosci 2004; 19:1591-600. [PMID: 15066155 DOI: 10.1111/j.1460-9568.2004.03258.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Abstract It is still a matter of dispute whether the expression of hippocampal long-term potentiation (LTP) is due to enhanced transmitter release or enhanced postsynaptic sensitivity. Recently we developed a novel method to monitor synaptically released glutamate. In this method, brain slice preparations are stained with a voltage-sensitive dye RH155 which preferentially stains glial cells, and synaptically induced glial depolarization (SIGD) are optically detected in the presence of the blockers for ionotropic glutamate receptors. We have previously shown that SIGD is due to uptake of synaptically released glutamate by glial glutamate transporters. Here we applied this method to examine change in glutamate release during hippocampal LTP. To examine mossy-CA3 LTP, stimulating electrodes were placed in dentate gyrus and tetanic stimulation was delivered in the presence of 50 micro m APV. The amplitude of SIGD after inducing LTP was significantly greater than that in control experiments in which tetanus was not delivered. The amplitude of SIGD after inducing LTP by a brief (3-5 min) application of 50 micro m forskolin was also significantly greater than that in control experiments. At the Schaffer-CA1 synapse, the change in the amplitude of SIGD during LTP induced either by 100 Hz tetanus LTP or 200 Hz tetanus was not significantly greater than that of control experiments. These results provide evidence for increased glutamate release from the presynaptic terminals as the expression mechanism for both tetanus-induced and forskolin-induced LTP at mossy-CA3 synapses, and evidence supporting a postsynaptic expression mechanism at Schaffer-CA1 synapses.
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Affiliation(s)
- Yoshinobu Kawamura
- Laboratory of Cellular Neurobiology, School of Life Science, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo 192-0392, Japan
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Shinoda Y, Tominaga-Yoshino K, Ogura A. The dendritic layer-specific persistent enhancement of synaptic transmission induced by repetitive activation of protein kinase A. Neurosci Res 2003; 47:191-200. [PMID: 14512143 DOI: 10.1016/s0168-0102(03)00199-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Synaptic plasticity, the cellular basis of brain memory, is established through at least two phases: short-term and long-term plasticity. It is assumed that the short-term plasticity instantaneously provoked in pre-existing synapses, as represented by a long-term potentiation (LTP) in the mammalian hippocampus, is converted to the long-term plasticity that develops slowly accompanying the formation of new synapses. However, this conversion has scarcely been analyzed primarily because of the lack of the model system. Recently, we found that a repeated activation of protein kinase A (PKA), but not a single activation of PKA, led to a slowly-developing long-lasting enhancement of synaptic strength coupled with synaptogenesis in cultured rat hippocampus and proposed that this phenomenon would serve as the required model system. In the present study, we investigated the geographical aspect of this phenomenon using a high-speed voltage-sensitive dye (VSD) imaging methodology. Before doing this, we had to overcome the difficulties in applying this methodology to the quantitative analysis on the cultured hippocampal slices. Those difficulties are multiple types of signal decay and a large variance in the number of cells among specimens. After resolving these problems we found that the enhancement of synaptic efficacy in the CA1 stratum radiatum occurred predominantly in the proximal dendritic layer.
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Affiliation(s)
- Yo Shinoda
- Department of Biology, Graduate School of Science, Osaka University, Machikaneyama-cho 1-1, Toyonaka, Osaka 560-0043, Japan
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Kasuga A, Enoki R, Hashimoto Y, Akiyama H, Kawamura Y, Inoue M, Kudo Y, Miyakawa H. Optical detection of dendritic spike initiation in hippocampal CA1 pyramidal neurons. Neuroscience 2003; 118:899-907. [PMID: 12732236 DOI: 10.1016/s0306-4522(03)00061-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Previous studies have shown that spikes can be generated in the dendrites of CA1 pyramidal neurons. Some have suggested that, in response to synaptic inputs, spikes are initiated near the soma and propagate back into the dendrites, but some recent studies have shown that intense synaptic inputs initiate spikes in the dendrite. Here, we report the optical detection of spike propagation along the apical dendrites of hippocampal pyramidal neurons. Rat hippocampal slices were stained with the fluorescent voltage-sensitive dye, JPW1114, and optical signals monitored using a 16 x 16 photodiode array system at a frame rate of 4 kHz. A stimulating electrode was placed at the boundary between the stratum (str.) lacnosum-moleculare and the str. radiatum to stimulate the Schaffer collateral, and fast and slow signal components were detected in the dendritic and somatic regions. By comparing the optical signals with whole-cell recordings, we confirmed that the fast component was due to a population of dendritic spikes in pyramidal neurons. The fast component appeared in dendritic locations near the input sites in response to synaptic activation, and signal onset at the soma was delayed by a few milliseconds compared with that at the input sites. Local perfusion of a Na(+) channel blocker near the soma eliminated the fast component at the soma, but had no effect on the fast component at the input sites. Our results indicate that dendritic spikes can be initiated in dendrites near the input site and propagate orthodromically toward the proximal dendrites and the soma.
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Affiliation(s)
- A Kasuga
- Laboratory of Cellular Neurobiology, School of Life Science, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo 192-0392, Japan
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