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Frequency-dependent gating of synaptic transmission and plasticity
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Encoding of spatio-temporal input characteristics by a CA1 pyramidal neuron model. PLoS Comput. Biol. 6:e1001038. doi: 10.1371/journal.pcbi.1001038
- J. Physiol
, 2010
"... The in vivo activity of CA1 pyramidal neurons alternates between regular spiking and bursting, but how these changes affect information processing remains unclear. Using a detailed CA1 pyramidal neuron model, we investigate how timing and spatial arrangement variations in synaptic inputs to the dist ..."
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The in vivo activity of CA1 pyramidal neurons alternates between regular spiking and bursting, but how these changes affect information processing remains unclear. Using a detailed CA1 pyramidal neuron model, we investigate how timing and spatial arrangement variations in synaptic inputs to the distal and proximal dendritic layers influence the information content of model responses. We find that the temporal delay between activation of the two layers acts as a switch between excitability modes: short delays induce bursting while long delays decrease firing. For long delays, the average firing frequency of the model response discriminates spatially clustered from diffused inputs to the distal dendritic tree. For short delays, the onset latency and inter-spike-interval succession of model responses can accurately classify input signals as temporally close or distant and spatially clustered or diffused across different stimulation protocols. These findings suggest that a CA1 pyramidal neuron may be capable of encoding and transmitting presynaptic spatiotemporal information about the activity of the entorhinal cortex-hippocampal network to higher brain regions via the selective use of either a temporal
Theta rhythmic stimulation of stratum lacunosum-moleculare in rat hippocampus contributes to associative LTP at a phase offset in stratum radiatum
- Journal of Neurophysiology
, 2004
"... of stratum lacunosum-moleculare in rat hippocampus contributes to associative LTP at a phase offset in stratum radiatum. J Neurophysiol 92: 1615–1624, 2004. First published May 5, 2004; 10.1152/jn.00848.2003. Computational modeling demonstrates that encoding and context-dependent retrieval of memori ..."
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of stratum lacunosum-moleculare in rat hippocampus contributes to associative LTP at a phase offset in stratum radiatum. J Neurophysiol 92: 1615–1624, 2004. First published May 5, 2004; 10.1152/jn.00848.2003. Computational modeling demonstrates that encoding and context-dependent retrieval of memories in region CA1 of the hippocampus will be most effective when the phase of strongest entorhinal input (to stratum lacunosum-moleculare) is offset from the phase of maximal induction of long-term potentiation at Schaffer collateral synapses (in s. radiatum). This would allow entorhinal input to play a role in both retrieval and encoding without engaging long-term potentiation (LTP) during retrieval. Experiments in brain slice preparations of the hippocampal formation tested the relationship between rhythmic input to s. lacunosum-moleculare and the time of maximal LTP induction at Schaffer collateral synapses in s. radiatum. Analysis of the data demonstrates a statistically significant difference in the induction of LTP for different time intervals between the end of each four-pulse train in s. lacunosum-moleculare and the single pulse s. radiatum stimulation. The time of maximal LTP induction was found to be �30 ms after the end of lacunosum-moleculare stimulation, consistent with the requirements of the model.
Strain-specific nicotinic modulation of glutamatergic transmission Jo ur na l o f C el l S ci en ce A cc ep te d m an us cr ip t An α7-GPC in neurite growth in the CA1 field of the rat hippocampus: August Copenhagen Irish versus Sprague-Dawley
- J Neurophysiol
, 2007
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Locationdependent excitatory synaptic interactions in pyramidal neuron dendrites
- PLoS Comput. Biol. 8:e1002599. doi
, 2012
"... Neocortical pyramidal neurons (PNs) receive thousands of excitatory synaptic contacts on their basal dendrites. Some act as classical driver inputs while others are thought to modulate PN responses based on sensory or behavioral context, but the biophysical mechanisms that mediate classical-contextu ..."
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Neocortical pyramidal neurons (PNs) receive thousands of excitatory synaptic contacts on their basal dendrites. Some act as classical driver inputs while others are thought to modulate PN responses based on sensory or behavioral context, but the biophysical mechanisms that mediate classical-contextual interactions in these dendrites remain poorly understood. We hypothesized that if two excitatory pathways bias their synaptic projections towards proximal vs. distal ends of the basal branches, the very different local spike thresholds and attenuation factors for inputs near and far from the soma might provide the basis for a classical-contextual functional asymmetry. Supporting this possibility, we found both in compartmental models and electrophysiological recordings in brain slices that the responses of basal dendrites to spatially separated inputs are indeed strongly asymmetric. Distal excitation lowers the local spike threshold for more proximal inputs, while having little effect on peak responses at the soma. In contrast, proximal excitation lowers the threshold, but also substantially increases the gain of distally-driven responses. Our findings support the view that PN basal dendrites possess significant analog computing capabilities, and suggest that the diverse forms of nonlinear response modulation seen in the neocortex, including uni-modal, cross-modal, and attentional effects, could depend in part on pathway-specific biases in the
Cell-specific extracellular signalregulated kinase activation by multiple G protein-coupled receptor families in hippocampus
- Mol. Pharmacol
, 2003
"... Several families of G protein-coupled receptors (GPCR) have been shown to activate extracellular signal-regulated kinase (ERK) in transfected cells and non-neuronal systems. However, little is known about GPCR activation of ERK in brain. Because ERK is an important component in the regulation of syn ..."
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Several families of G protein-coupled receptors (GPCR) have been shown to activate extracellular signal-regulated kinase (ERK) in transfected cells and non-neuronal systems. However, little is known about GPCR activation of ERK in brain. Because ERK is an important component in the regulation of synaptic plasticity, in this study we examined ERK activation by three families of GPCR that respond to major neuromodulatory neu-rotransmitters in the hippocampus. We used an immunocyto-chemical approach to examine ERK activation by muscarinic acetylcholine (mAChR), metabotropic glutamate (mGluR), and -adrenergic (-AR) receptors in CA1 neurons of mouse hip-pocampal slices. Because these GPCR families comprise re-ceptors coupling to each of the major heterotrimeric G proteins, we examined whether ERK activation differs according to G-protein coupling. By using immunocytochemistry, we were able to examine not only whether each family of receptors activates ERK, but also the cellular populations and subcellular distribu-tions of activated ERK. We demonstrated that M1 mAChRs and group I mGluRs, both of which are Gq-coupled receptors, ac-tivate ERK in CA1 pyramidal neurons, although activation in response to mAChR is more robust. The Gi/o-coupled group II mGluRs activate ERK in glia scattered throughout CA1, and Gs-coupled -AR receptors activate ERK in scattered interneu-rons. Thus, we demonstrated that GPCR coupling to Gq, Gi/o, and Gs all activate ERK in the hippocampus, although each does so with unique properties and distributions. Mitogen-activated protein kinases are a family of serine/ threonine protein kinases that play a role in a large number of neural functions, including cell survival (Yan and Greene, 1998), differentiation (Cowley et al., 1994), nociception (Ka-rim et al., 2001), and learning and memory (Impey et al.,
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, 2006
"... Modulation of excitability in CA1 pyramidal neurons via the interplay ..."
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Neuron a N M
"... RESULTSet al., 2014). An important goal of such investigations is to under-stand how the rate and timing of spikes in neurons of a down-Experiments were carried out while animals ran on a linear track (250 cm long), a Tmaze, or open field (Mizuseki et al., 2009,2012;domain. CA1 pyramidal cells were ..."
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RESULTSet al., 2014). An important goal of such investigations is to under-stand how the rate and timing of spikes in neurons of a down-Experiments were carried out while animals ran on a linear track (250 cm long), a Tmaze, or open field (Mizuseki et al., 2009,2012;domain. CA1 pyramidal cells were phase-locked mainly to fast gamma (>100 Hz) LFP patterns restricted to CA1, which were strongest at the theta trough. While theta phase coordination of spiking across entorhinal-hippocampal regions depended on memory demands, LFP gamma patterns below 100 Hz in the hippocampus were consistently layer specific and largely reflected afferent activity. Gamma synchronization as a mechanism for interre-gional communication thus rapidly loses efficacy at higher frequencies.
Universidade Federal do Rio Grande
, 2013
"... doi: 10.3389/fnsyn.2013.00005 The temporoammonic input to the hippocampal CA1 region displays distinctly different synaptic plasticity compared to the Schaffer collateral input in vivo: significance for synaptic information processing ..."
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doi: 10.3389/fnsyn.2013.00005 The temporoammonic input to the hippocampal CA1 region displays distinctly different synaptic plasticity compared to the Schaffer collateral input in vivo: significance for synaptic information processing
