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Robustness effect of gap junctions between Golgi cells on cerebellar cortex oscillations.

Simões de Souza FM, De Schutter E - Neural Syst Circuits (2011)

Bottom Line: Conversely, when GoCs were synaptically connected in the granular layer, gap junctions increased the power of the oscillations, but the oscillations were primarily driven by the synaptic feedback loop between GoCs and GCs, and the gap junctions did not change oscillation frequency or the mean firing rate of either GoCs or GCs.Our modeling results suggest that gap junctions between GoCs increase the robustness of cerebellar cortex oscillations that are primarily driven by the feedback loop between GoCs and GCs.The robustness effect of gap junctions on synaptically driven oscillations observed in our model may be a general mechanism, also present in other regions of the brain.

View Article: PubMed Central - HTML - PubMed

Affiliation: Computational Neuroscience Unit, Okinawa Institute of Science and Technology, Okinawa 904-0411, Japan. erik@oist.jp.

ABSTRACT

Background: Previous one-dimensional network modeling of the cerebellar granular layer has been successfully linked with a range of cerebellar cortex oscillations observed in vivo. However, the recent discovery of gap junctions between Golgi cells (GoCs), which may cause oscillations by themselves, has raised the question of how gap-junction coupling affects GoC and granular-layer oscillations. To investigate this question, we developed a novel two-dimensional computational model of the GoC-granule cell (GC) circuit with and without gap junctions between GoCs.

Results: Isolated GoCs coupled by gap junctions had a strong tendency to generate spontaneous oscillations without affecting their mean firing frequencies in response to distributed mossy fiber input. Conversely, when GoCs were synaptically connected in the granular layer, gap junctions increased the power of the oscillations, but the oscillations were primarily driven by the synaptic feedback loop between GoCs and GCs, and the gap junctions did not change oscillation frequency or the mean firing rate of either GoCs or GCs.

Conclusion: Our modeling results suggest that gap junctions between GoCs increase the robustness of cerebellar cortex oscillations that are primarily driven by the feedback loop between GoCs and GCs. The robustness effect of gap junctions on synaptically driven oscillations observed in our model may be a general mechanism, also present in other regions of the brain.

No MeSH data available.


Mean firing rate of the neurons in the network. (A, B) Golgi cell (GoC) layer mean firing rate; (C, D) GC layer mean firing rate. (A, C) network without gap junctions between GoCs; (B, D) network with gap junctions between GoCs. The x axis = MF input rate (Hz); y axis = parallel fiber (PF) synaptic weight (%); and z axis = mean firing frequency (Hz).
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Figure 5: Mean firing rate of the neurons in the network. (A, B) Golgi cell (GoC) layer mean firing rate; (C, D) GC layer mean firing rate. (A, C) network without gap junctions between GoCs; (B, D) network with gap junctions between GoCs. The x axis = MF input rate (Hz); y axis = parallel fiber (PF) synaptic weight (%); and z axis = mean firing frequency (Hz).

Mentions: After studying the responses of the network to sinusoidal waves, the network was stimulated directly by synaptic inputs with varying rates of MF input on GoCs and GCs. We also investigated the influence of the strength of the PFs on the network activity in the presence and absence of gap junctions between GoCs. Initially, we tested the influence of the synaptic inputs on the MFRs of GoCs and GCs. MFRs increased with increasing MF rates and PF strengths (Figure 5A, C), and gap junctions did not affect the MFRs of the neurons in the network (Figure 5B, D; see Additional file 1, Figure S7). GC MFRs were 0.5 to 3 Hz and GoC firing rates were 20 to 120 Hz (see Methods). In vivo, GC and GoC MFRs are 2 to 7 Hz [6,63-65].


Robustness effect of gap junctions between Golgi cells on cerebellar cortex oscillations.

Simões de Souza FM, De Schutter E - Neural Syst Circuits (2011)

Mean firing rate of the neurons in the network. (A, B) Golgi cell (GoC) layer mean firing rate; (C, D) GC layer mean firing rate. (A, C) network without gap junctions between GoCs; (B, D) network with gap junctions between GoCs. The x axis = MF input rate (Hz); y axis = parallel fiber (PF) synaptic weight (%); and z axis = mean firing frequency (Hz).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3278348&req=5

Figure 5: Mean firing rate of the neurons in the network. (A, B) Golgi cell (GoC) layer mean firing rate; (C, D) GC layer mean firing rate. (A, C) network without gap junctions between GoCs; (B, D) network with gap junctions between GoCs. The x axis = MF input rate (Hz); y axis = parallel fiber (PF) synaptic weight (%); and z axis = mean firing frequency (Hz).
Mentions: After studying the responses of the network to sinusoidal waves, the network was stimulated directly by synaptic inputs with varying rates of MF input on GoCs and GCs. We also investigated the influence of the strength of the PFs on the network activity in the presence and absence of gap junctions between GoCs. Initially, we tested the influence of the synaptic inputs on the MFRs of GoCs and GCs. MFRs increased with increasing MF rates and PF strengths (Figure 5A, C), and gap junctions did not affect the MFRs of the neurons in the network (Figure 5B, D; see Additional file 1, Figure S7). GC MFRs were 0.5 to 3 Hz and GoC firing rates were 20 to 120 Hz (see Methods). In vivo, GC and GoC MFRs are 2 to 7 Hz [6,63-65].

Bottom Line: Conversely, when GoCs were synaptically connected in the granular layer, gap junctions increased the power of the oscillations, but the oscillations were primarily driven by the synaptic feedback loop between GoCs and GCs, and the gap junctions did not change oscillation frequency or the mean firing rate of either GoCs or GCs.Our modeling results suggest that gap junctions between GoCs increase the robustness of cerebellar cortex oscillations that are primarily driven by the feedback loop between GoCs and GCs.The robustness effect of gap junctions on synaptically driven oscillations observed in our model may be a general mechanism, also present in other regions of the brain.

View Article: PubMed Central - HTML - PubMed

Affiliation: Computational Neuroscience Unit, Okinawa Institute of Science and Technology, Okinawa 904-0411, Japan. erik@oist.jp.

ABSTRACT

Background: Previous one-dimensional network modeling of the cerebellar granular layer has been successfully linked with a range of cerebellar cortex oscillations observed in vivo. However, the recent discovery of gap junctions between Golgi cells (GoCs), which may cause oscillations by themselves, has raised the question of how gap-junction coupling affects GoC and granular-layer oscillations. To investigate this question, we developed a novel two-dimensional computational model of the GoC-granule cell (GC) circuit with and without gap junctions between GoCs.

Results: Isolated GoCs coupled by gap junctions had a strong tendency to generate spontaneous oscillations without affecting their mean firing frequencies in response to distributed mossy fiber input. Conversely, when GoCs were synaptically connected in the granular layer, gap junctions increased the power of the oscillations, but the oscillations were primarily driven by the synaptic feedback loop between GoCs and GCs, and the gap junctions did not change oscillation frequency or the mean firing rate of either GoCs or GCs.

Conclusion: Our modeling results suggest that gap junctions between GoCs increase the robustness of cerebellar cortex oscillations that are primarily driven by the feedback loop between GoCs and GCs. The robustness effect of gap junctions on synaptically driven oscillations observed in our model may be a general mechanism, also present in other regions of the brain.

No MeSH data available.