In vivo dendritic calcium dynamics in neocortical pyramidal neurons

  title={In vivo dendritic calcium dynamics in neocortical pyramidal neurons},
  author={Karel Svoboda and Winfried Denk and David Kleinfeld and David W. Tank},
THE dendrites of mammalian pyramidal neurons contain a rich collection of active conductances that can support Na+ and Ca2+ action potentials (for a review see ref. 1). The presence, site of initiation, and direction of propagation of Na+ and Ca2+ action potentials are, however, controversial2, and seem to be sensitive to resting membrane potential, ionic composition, and degree of channel inactivation, and depend on the intensity and pattern of synaptic stimulation. This makes it difficult to… 
Spread of dendritic excitation in layer 2/3 pyramidal neurons in rat barrel cortex in vivo
In layer 2/3 pyramidal neurons of barrel cortex in vivo, calcium ion concentration ([Ca2+]) transients in apical dendrites evoked by sodium action potentials are limited to regions close to the soma.
In vivo dendritic calcium dynamics in deep-layer cortical pyramidal neurons
Two-photon microscopy is used to demonstrate Ca2+ electrogenesis in apical dendrites of deep-layer pyramidal neurons of rat barrel cortex in vivo, suggesting variable coupling between dendrite and soma.
Fiberoptic system for recording dendritic calcium signals in layer 5 neocortical pyramidal cells in freely moving rats.
This work presents a novel approach for recording Ca2+ signals in the dendrites of populations of layer 5 pyramidal neurons in vivo, which ensures that all recorded fluorescence changes are due to intracellular Ca2+, and demonstrates that the in vivo signal-to-noise ratio recorded is comparable to conventional camera-based imaging systems used in vitro.
Dependence of calcium influx in neocortical cells on temporal structure of depolarization, number of spikes, and blockade of NMDA receptors
Differences in intracellular [Ca2+] increases may be one reason for differential effects of purely postsynaptic challenges on synaptic transmission.
In vivo calcium accumulation in presynaptic and postsynaptic dendrites of visual interneurons.
The described differences between the two cell classes may reflect the following computational tasks of these neurons: CH cells relay retinotopic information within the lobula plate via dendritic synapses with pronounced spatial low-pass filtering, and HS cells are output neurons of the Lobula plate, in which the slow, local calcium accumulation may be suitable for local modulatory functions.
Supralinear Ca2+ Influx into Dendritic Tufts of Layer 2/3 Neocortical Pyramidal Neurons In Vitro and In Vivo
It is found that backpropagation of action potentials into the dendritic arbor is actively supported by Na+ channels both in vitro and in vivo and enables layer 2/3 neurons to integrate ascending sensory input from layer 4 and associative input to layer 1.
Calcium coding and adaptive temporal computation in cortical pyramidal neurons.
  • X. Wang
  • Biology
    Journal of neurophysiology
  • 1998
It is demonstrated that the intracellular [Ca2+] signal can encode the instantaneous neuronal firing rate and that the conductance-based model can be reduced to a simple calcium-model of neuronal activity that faithfully predicts the neuronal firing output even when the input varies relatively rapidly in time.
Contributions of Voltage-Gated Ca2+ Channels in the Proximal versus Distal Dendrites to Synaptic Integration in Prefrontal Cortical Neurons
The electrogenesis of synaptically activated dendritic Ca2+-mediated potentials, which may contribute to synaptic signal integration in pyramidal cells, was examined in rat layers V–VI prefrontal cortical (PFC) neurons in vitro and suggested that the high voltage-activated Ca1+ potentials that amplify distal EPSPs are primarily generated in the proximal stem of the apical dendrite.
Weak Sinusoidal Electric Fields Entrain Spontaneous Ca Transients in the Dendritic Tufts of CA1 Pyramidal Cells in Rat Hippocampal Slice Preparations
The results suggest that population of pyramidal cells might be able to detect electric fields with biologically relevant intensity by modulating the timing of dendritic spikes.
Action Potential Propagation in Dendrites of Rat Mitral Cells In Vivo
Results suggest that the presence of release sites in dendrites is accompanied by an “axonal-like behavior” of the entire dendritic tree of mitral cells, including their most distal dendrite branches.


Stepwise repolarization from Ca2+ plateaus in neocortical pyramidal cells: evidence for nonhomogeneous distribution of HVA Ca2+ channels in dendrites
These findings provide strong evidence that Ca2+ spike initiation occurs at electrotonically separated “hot spots” in the dendrites, and that voltage dependence of the Ca2- channels that underlie the spikes is the same at all sites.
Optical imaging of calcium accumulation in hippocampal pyramidal cells during synaptic activation
In situ micro-fluorometric imaging is used in brain slices to directly measure the spatial distribution of calcium accumulation in guinea-pig CA1 pyramidal cells during trains of orthodromic synaptic stimulation and demonstrates a marked segregation of calcium-channel activity and directly show a spatial distributionof calcium accumulation during orthodromeic synaptic activation.
Active propagation of somatic action potentials into neocortical pyramidal cell dendrites
To determine the site of initiation of action potentials, simultaneous whole-cell recordings were made from the soma and the apical dendrite or axon of the same cell and showed thataction potentials are initiated first in the axon and then actively propagate back into the dendritic tree.
The spread of Na+ spikes determines the pattern of dendritic Ca2+ entry into hippocampal neurons
The results indicate that Ca2+ entry into dendrite is triggered by Na+ spikes that actively invade the dendrites, and an activity-dependent process that modulates the invasion of spikes into thedendrites and progressively restricts Ca2- entry to more proximal dendritic regions is observed.
Apical dendrites of the neocortex: correlation between sodium- and calcium-dependent spiking and pyramidal cell morphology
  • HG Kim, B. Connors
  • Biology
    The Journal of neuroscience : the official journal of the Society for Neuroscience
  • 1993
The results show that voltage-dependent Na+ and Ca2+ currents are present in distal apical dendrites, in variable densities, and significantly modify distal synaptic events.
IPSPs modulate spike backpropagation and associated [Ca2+]i changes in the dendrites of hippocampal CA1 pyramidal neurons.
The effects of synaptic inhibition on backpropagating Na+ spikes in the apical dendrites of CA1 pyramidal neurons in transverse slices from the rat hippocampus suggest that this effect of inhibition is different from its usual function in synaptic integration because spike generation and propagation down the axon are not significantly affected.
Frequency-dependent propagation of sodium action potentials in dendrites of hippocampal CA1 pyramidal neurons.
The results show that the action-potential amplitude and the spatial extent of their propagation in the dendrites is frequency dependent.
Intradendritic recordings from hippocampal neurons.
Dendritic activity in guinea pig hippocampal CA1 and CA3 pyramidal neurons was examined by using an in vitro preparation and found that potential postsynaptic amplifying mecahnism was not ordinarily functional because even suprathreshold orthodromic activation did not normally evoke bursting in dendrites.