Opposing effects of intrinsic conductance and correlated synaptic input on Vm-fluctuations during network activity
Neurons often receive massive concurrent bombardment of synaptic inhibition and excitation during functional network activity. This increases membrane conductance and causes fluctuations in membrane potential (Vm) and spike timing. The conductance increase is commonly attributed to synaptic conducta...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2012-07-01
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| Series: | Frontiers in Computational Neuroscience |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fncom.2012.00040/full |
| _version_ | 1831552527616704512 |
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| author | Jens eKolind Jorn eHounsgaard Rune W. Berg |
| author_facet | Jens eKolind Jorn eHounsgaard Rune W. Berg |
| author_sort | Jens eKolind |
| collection | DOAJ |
| description | Neurons often receive massive concurrent bombardment of synaptic inhibition and excitation during functional network activity. This increases membrane conductance and causes fluctuations in membrane potential (Vm) and spike timing. The conductance increase is commonly attributed to synaptic conductance, but also includes the intrinsic conductances recruited during network activity. These two sources of conductance have contrasting dynamic properties at subthreshold membrane potentials. Synaptic transmitter gated conductance changes abruptly and briefly with each presynaptic action potential. If the spikes arrive at random times the changes in synaptic conductance are therefore stochastic and rapid during intense network activity. In comparison, subthreshold intrinsic conductances vary smoothly in time. In the present study this discrepancy is investigated using two conductance-based models: a 1-compartment model and a 2-compartment with realistic slow intrinsic conductances. We examine the effects of varying the relative contributions of non-fluctuating intrinsic conductance with fluctuating concurrent inhibitory and excitatory synaptic conductance. For given levels of correlation in the synaptic input we find that the magnitude of the membrane fluctuations uniquely determines the relative contribution of synaptic and intrinsic conductance. We also quantify how Vm-fluctuations vary with synaptic correlations for fixed ratios of synaptic and intrinsic conductance. Interestingly, the levels of Vm-fluctuations and conductance observed experimentally during functional network activity leave little room for intrinsic conductance to contribute. Even without intrinsic conductances the variance in Vm-fluctuations can only be explained by a high degree of correlated firing among presynaptic neurons. |
| first_indexed | 2024-12-17T03:28:09Z |
| format | Article |
| id | doaj.art-2e2643a62efb4243b685d1d247208adb |
| institution | Directory Open Access Journal |
| issn | 1662-5188 |
| language | English |
| last_indexed | 2024-12-17T03:28:09Z |
| publishDate | 2012-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Computational Neuroscience |
| spelling | doaj.art-2e2643a62efb4243b685d1d247208adb2022-12-21T22:05:20ZengFrontiers Media S.A.Frontiers in Computational Neuroscience1662-51882012-07-01610.3389/fncom.2012.0004027144Opposing effects of intrinsic conductance and correlated synaptic input on Vm-fluctuations during network activityJens eKolind0Jorn eHounsgaard1Rune W. Berg2University of CopenhagenUniversity of CopenhagenUniversity of CopenhagenNeurons often receive massive concurrent bombardment of synaptic inhibition and excitation during functional network activity. This increases membrane conductance and causes fluctuations in membrane potential (Vm) and spike timing. The conductance increase is commonly attributed to synaptic conductance, but also includes the intrinsic conductances recruited during network activity. These two sources of conductance have contrasting dynamic properties at subthreshold membrane potentials. Synaptic transmitter gated conductance changes abruptly and briefly with each presynaptic action potential. If the spikes arrive at random times the changes in synaptic conductance are therefore stochastic and rapid during intense network activity. In comparison, subthreshold intrinsic conductances vary smoothly in time. In the present study this discrepancy is investigated using two conductance-based models: a 1-compartment model and a 2-compartment with realistic slow intrinsic conductances. We examine the effects of varying the relative contributions of non-fluctuating intrinsic conductance with fluctuating concurrent inhibitory and excitatory synaptic conductance. For given levels of correlation in the synaptic input we find that the magnitude of the membrane fluctuations uniquely determines the relative contribution of synaptic and intrinsic conductance. We also quantify how Vm-fluctuations vary with synaptic correlations for fixed ratios of synaptic and intrinsic conductance. Interestingly, the levels of Vm-fluctuations and conductance observed experimentally during functional network activity leave little room for intrinsic conductance to contribute. Even without intrinsic conductances the variance in Vm-fluctuations can only be explained by a high degree of correlated firing among presynaptic neurons.http://journal.frontiersin.org/Journal/10.3389/fncom.2012.00040/fullexcitationinhibitionnetworkfluctuationsintrinsic propertiesbalanced |
| spellingShingle | Jens eKolind Jorn eHounsgaard Rune W. Berg Opposing effects of intrinsic conductance and correlated synaptic input on Vm-fluctuations during network activity Frontiers in Computational Neuroscience excitation inhibition network fluctuations intrinsic properties balanced |
| title | Opposing effects of intrinsic conductance and correlated synaptic input on Vm-fluctuations during network activity |
| title_full | Opposing effects of intrinsic conductance and correlated synaptic input on Vm-fluctuations during network activity |
| title_fullStr | Opposing effects of intrinsic conductance and correlated synaptic input on Vm-fluctuations during network activity |
| title_full_unstemmed | Opposing effects of intrinsic conductance and correlated synaptic input on Vm-fluctuations during network activity |
| title_short | Opposing effects of intrinsic conductance and correlated synaptic input on Vm-fluctuations during network activity |
| title_sort | opposing effects of intrinsic conductance and correlated synaptic input on vm fluctuations during network activity |
| topic | excitation inhibition network fluctuations intrinsic properties balanced |
| url | http://journal.frontiersin.org/Journal/10.3389/fncom.2012.00040/full |
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