scholarly journals Transient depolarization and spontaneous voltage fluctuations in isolated single cells from guinea pig ventricles. Calcium-mediated membrane potential fluctuations.

1982 ◽  
Vol 51 (2) ◽  
pp. 142-151 ◽  
Author(s):  
H Matsuda ◽  
A Noma ◽  
Y Kurachi ◽  
H Irisawa
1975 ◽  
Vol 191 (1105) ◽  
pp. 561-565 ◽  

Glutamate-induced potential changes have been recorded with intracellular electrodes in nerve cells of the squid. The responses are accompanied by small voltage fluctuations which resemble postsynaptic ‘membrane noise’ observed at neuromuscular junctions. Certain limitations are discussed in extending the noise analysis to neurons with multiple synaptic inputs.


2007 ◽  
Vol 97 (4) ◽  
pp. 3015-3023 ◽  
Author(s):  
A. Kepecs ◽  
S. Raghavachari

Two-state voltage fluctuations between a hyperpolarized down-state and a depolarized up-state have been observed experimentally in a wide variety of neurons across brain regions. Using a biophysical model, we show that synaptic input by NMDA receptors can cause such membrane potential fluctuations. In this model, when a neuron is driven by two input pathways with different AMPA/NMDA receptor content, the NMDA-rich input causes up-state transitions, whereas the AMPA-rich input generates spikes only in the up-state. Therefore the NMDA-rich pathway can gate input from an AMPA pathway in an all-or-none fashion by switching between different membrane potential states. Furthermore, once in the up-state, the NMDA-rich pathway multiplicatively increases the gain of a neuron responding to AMPA-rich input. This proposed mechanism for two-state fluctuations directly suggests specific computations, such as gating and gain modulation based on the distinct receptor composition of different neuronal pathways. The dynamic gating of input by up- and down-states may be an elementary operation for the selective routing of signals in neural circuits, which may explain the ubiquity of two-state fluctuations across brain regions.


1997 ◽  
Vol 77 (4) ◽  
pp. 1697-1715 ◽  
Author(s):  
Edward A. Stern ◽  
Anthony E. Kincaid ◽  
Charles J. Wilson

Stern, Edward A., Anthony E. Kincaid, and Charles J. Wilson. Spontaneous subthreshold membrane potential fluctuations and action potential variability of rat corticostriatal and striatal neurons in vivo. J. Neurophysiol. 77: 1697–1715, 1997. We measured the timing of spontaneous membrane potential fluctuations and action potentials of medial and lateral agranular corticostriatal and striatal neurons with the use of in vivo intracellular recordings in urethan-anesthetized rats. All neurons showed spontaneous subthreshold membrane potential shifts from 7 to 32 mV in amplitude, fluctuating between a hyperpolarized down state and depolarized up state. Action potentials arose only during the up state. The membrane potential state transitions showed a weak periodicity with a peak frequency near 1 Hz. The peak of the frequency spectra was broad in all neurons, indicating that the membrane potential fluctuations were not dominated by a single periodic function. At frequencies >1 Hz, the log of magnitude decreased linearly with the log of frequency in all neurons. No serial dependence was found for up and down state durations, or for the time between successive up or down state transitions, showing that the up and down state transitions are not due to superimposition of noisy inputs onto a single frequency. Monte Carlo simulations of stochastic synaptic inputs to a uniform finite cylinder showed that the Fourier spectra obtained for corticostriatal and striatal neurons are inconsistent with a Poisson-like synaptic input, demonstrating that the up state is not due to an increase in the strength of an unpatterned synaptic input. Frequency components arising from state transitions were separated from those arising from the smaller membrane potential fluctuations within each state. A larger proportion of the total signal was represented by the fluctuations within states, especially in the up state, than was predicted by the simulations. The individual state spectra did not correspond to those of random synaptic inputs, but reproduced the spectra of the up and down state transitions. This suggests that the process causing the state transitions and the process responsible for synaptic input may be the same. A high-frequency periodic component in the up states was found in the majority of the corticostriatal cells in the sample. The average size of the component was not different between neurons injected with QX-314 and control neurons. The high-frequency component was not seen in any of our sample of striatal cells. Corticostriatal and striatal neurons' coefficients of variation of interspike intervals ranged from 1.0 to 1.9. When interspike intervals including a down state were subtracted from the calculation, the coefficient of variation ranged from 0.4 to 1.1, indicating that a substantial proportion of spike interval variance was due to the subthreshold membrane potential fluctuations.


1987 ◽  
Vol 103 (3) ◽  
pp. 283-286
Author(s):  
S. I. Zakharov ◽  
K. Yu. Bogdanov ◽  
A. V. Zaitsev ◽  
L. V. Rozenshtraukh

2011 ◽  
Vol 589 (17) ◽  
pp. 4365-4381 ◽  
Author(s):  
Jan M. Schulz ◽  
Toni L. Pitcher ◽  
Shakuntala Savanthrapadian ◽  
Jeffery R. Wickens ◽  
Manfred J. Oswald ◽  
...  

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