The origins of two-state spontaneous membrane potential fluctuations of neostriatal spiny neurons

Striatal projection neurons, the medium spiny neurons (MSNs), play a crucial role in various motor and cognitive functions. MSNs express either D1- or D2-type dopamine receptors and initiate the direct-pathway (dMSNs) or indirect pathways (iMSNs) of the basal ganglia, respectively. dMSNs have been shown to receive more inhibition than iMSNs from intrastriatal sources. Based on these findings, computational modeling of the striatal network has predicted that under healthy conditions dMSNs should receive more total input than iMSNs. To test this prediction, we analyzed in vivo whole cell recordings from dMSNs and iMSNs in healthy and dopamine-depleted (6OHDA) anaesthetized mice. By comparing their membrane potential fluctuations, we found that dMSNs exhibited considerably larger membrane potential fluctuations over a wide frequency range. Furthermore, by comparing the spike-triggered average membrane potentials, we found that dMSNs depolarized toward the spike threshold significantly faster than iMSNs did. Together, these findings (in particular the STA analysis) corroborate the theoretical prediction that direct-pathway MSNs receive stronger total input than indirect-pathway neurons. Finally, we found that dopamine-depleted mice exhibited no difference between the membrane potential fluctuations of dMSNs and iMSNs. These data provide new insights into the question of how the lack of dopamine may lead to behavioral deficits associated with Parkinson’s disease. NEW & NOTEWORTHY The direct and indirect pathways of the basal ganglia originate from the D1- and D2-type dopamine receptor expressing medium spiny neurons (dMSNs and iMSNs). Theoretical results have predicted that dMSNs should receive stronger synaptic input than iMSNs. Using in vivo intracellular membrane potential data, we provide evidence that dMSNs indeed receive stronger input than iMSNs, as has been predicted by the computational model.

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Direct Pathway Neurons in Mouse Dorsolateral Striatum In Vivo Receive Stronger Synaptic Input than Indirect Pathway Neurons

10.1101/651711 ◽

2019 ◽

Author(s):

Marko Filipović ◽

Maya Ketzef ◽

Ramon Reig ◽

Ad Aertsen ◽

Gilad Silberberg ◽

...

Keyword(s):

Membrane Potential ◽

Synaptic Input ◽

Excitatory Input ◽

Medium Spiny Neurons ◽

Indirect Pathway ◽

Potential Fluctuations ◽

Direct Pathway ◽

Spiny Neurons ◽

Membrane Potential Fluctuations

AbstractStriatal projection neurons, the medium spiny neurons (MSNs), play a crucial role in various motor and cognitive functions. MSNs express either D1 or D2 type dopamine receptors and initiate the direct-pathway (dMSNs) or indirect pathways (iMSNs) of the basal ganglia, respectively. dMSNs have been shown to receive more inhibition than iMSNs from intrastriatal sources. Based on these findings, computational modelling of the striatal network has predicted that under healthy conditions dMSNs should receive more excitatory input than iMSNs. To test this prediction, we analyzed in vivo whole-cell recordings from dMSNs and iMSNs in healthy and dopamine-depleted (6OHDA) anaesthetized mice. By comparing their membrane potential fluctuations, we found that dMSNs exhibited considerably larger membrane potential fluctuations over a wide frequency range. Furthermore, by comparing the spike-triggered average membrane potentials, we found that dMSNs depolarized towards the spike threshold significantly faster than iMSNs did. Together, these finding corroborate the theoretical prediction that direct-pathway MSNs receive stronger input than indirect-pathway neurons. Finally, we found that dopamine-depleted mice exhibited no difference between the membrane potential fluctuations of dMSNs and iMSNs. These data provide new insights into the question how a lack of dopamine may lead to behavior deficits associated with Parkinson’s disease.Significance statementThe direct and indirect pathways of the basal ganglia originate from the D1 and D2 type dopamine receptor expressing medium spiny neurons (dMSNs and iMSNs), respectively. To understand the role of the striatum in brain function and dysfunction it is important to characterize the differences in synaptic inputs to the two MSN types. Theoretical results predicted that dMSNs should receive stronger excitatory input than iMSNs. Here, we studied membrane potential fluctuation statistics of MSNs recorded in vivo in anaesthetized mice and found that dMSNs, indeed, received stronger synaptic input than iMSNs. We corroborated this finding by spike-triggered membrane potential analysis, showing that dMSNs spiking required more synaptic input than iMSNs spiking did, as had been predicted by computational models.

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Synaptic and Non-Synaptic Control of Membrane Potential Fluctuations in Bulbar Respiratory Neurons of Cats

Control of Breathing and Its Modeling Perspective ◽

10.1007/978-1-4757-9847-0_6 ◽

1992 ◽

pp. 43-50

Author(s):

Ryuji Takeda ◽

Akira Haji

Keyword(s):

Membrane Potential ◽

Respiratory Neurons ◽

Potential Fluctuations ◽

Synaptic Control ◽

Membrane Potential Fluctuations

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Spontaneous Subthreshold Membrane Potential Fluctuations and Action Potential Variability of Rat Corticostriatal and Striatal Neurons In Vivo

Journal of Neurophysiology ◽

10.1152/jn.1997.77.4.1697 ◽

1997 ◽

Vol 77 (4) ◽

pp. 1697-1715 ◽

Cited By ~ 224

Author(s):

Edward A. Stern ◽

Anthony E. Kincaid ◽

Charles J. Wilson

Keyword(s):

Membrane Potential ◽

Synaptic Input ◽

High Frequency ◽

Action Potentials ◽

State Transitions ◽

Striatal Neurons ◽

Interspike Intervals ◽

Potential Fluctuations ◽

Membrane Potential Fluctuations

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.

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Membrane potential fluctuations produced by glutamate in nerve cells of the squid

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1975.0146 ◽

1975 ◽

Vol 191 (1105) ◽

pp. 561-565 ◽

Cited By ~ 5

Keyword(s):

Membrane Potential ◽

Neuromuscular Junctions ◽

Noise Analysis ◽

Postsynaptic Membrane ◽

Nerve Cells ◽

Voltage Fluctuations ◽

Potential Fluctuations ◽

Synaptic Inputs ◽

Small Voltage ◽

Membrane Potential Fluctuations

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.

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