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Synaptic representation of locomotion in single cerebellar granule cells.

Powell K, Mathy A, Duguid I, Häusser M - Elife (2015)

Bottom Line: Here, we use in vivo patch-clamp recordings to show that locomotion can be directly read out from mossy fiber synaptic input and spike output in single granule cells.The increase in granule cell spiking during locomotion is enhanced by glutamate spillover currents recruited during movement.Thus, synaptic input delivers remarkably rich information to single neurons during locomotion.

View Article: PubMed Central - PubMed

Affiliation: Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.

ABSTRACT
The cerebellum plays a crucial role in the regulation of locomotion, but how movement is represented at the synaptic level is not known. Here, we use in vivo patch-clamp recordings to show that locomotion can be directly read out from mossy fiber synaptic input and spike output in single granule cells. The increase in granule cell spiking during locomotion is enhanced by glutamate spillover currents recruited during movement. Surprisingly, the entire step sequence can be predicted from input EPSCs and output spikes of a single granule cell, suggesting that a robust gait code is present already at the cerebellar input layer and transmitted via the granule cell pathway to downstream Purkinje cells. Thus, synaptic input delivers remarkably rich information to single neurons during locomotion.

No MeSH data available.


Related in: MedlinePlus

Synaptic charge transfer with and without spillover.The synaptic charge transfer over 100 ms as a function of EPSC frequency with and without spillover.DOI:http://dx.doi.org/10.7554/eLife.07290.007
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fig2s1: Synaptic charge transfer with and without spillover.The synaptic charge transfer over 100 ms as a function of EPSC frequency with and without spillover.DOI:http://dx.doi.org/10.7554/eLife.07290.007

Mentions: To isolate the putative spillover components, we fit the fast EPSCs and separated them from the underlying slow current recorded at −70 mV (Figure 2A). The amplitude of the slow current was correlated with the EPSC frequency (Figure 2E shows this for an individual cell; Figure 2F for the population of n = 9 cells), such that the proportion of the total current carried by the fast EPSCs vs the slow current diminished with EPSC rate (Figure 2B), similar to what has been shown in vitro in response to trains of synaptic stimulation (Sargent et al., 2005). Since spillover results from synaptic accumulation of neurotransmitter, a delay would be expected between the peak of the EPSCs and that of the putative spillover current. Indeed, a cross-correlation between the instantaneous frequency of fast EPSCs and the slow currents showed a peak with a lag of 40 ms (Figure 2C), with the slow current lagging the fast events. Similarly, aligning the slow current on a burst of at least 5 EPSCs at 200 Hz or above exhibited a negative peak at positive delay (31 ms latency; 729 bursts from the 9 cells, Figure 2D). We further plotted the synaptic charge transfer over 100 ms as a function of EPSC rate with and without spillover (Figure 2—figure supplement 1). The spillover dramatically affects the slope of this curve.


Synaptic representation of locomotion in single cerebellar granule cells.

Powell K, Mathy A, Duguid I, Häusser M - Elife (2015)

Synaptic charge transfer with and without spillover.The synaptic charge transfer over 100 ms as a function of EPSC frequency with and without spillover.DOI:http://dx.doi.org/10.7554/eLife.07290.007
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4499793&req=5

fig2s1: Synaptic charge transfer with and without spillover.The synaptic charge transfer over 100 ms as a function of EPSC frequency with and without spillover.DOI:http://dx.doi.org/10.7554/eLife.07290.007
Mentions: To isolate the putative spillover components, we fit the fast EPSCs and separated them from the underlying slow current recorded at −70 mV (Figure 2A). The amplitude of the slow current was correlated with the EPSC frequency (Figure 2E shows this for an individual cell; Figure 2F for the population of n = 9 cells), such that the proportion of the total current carried by the fast EPSCs vs the slow current diminished with EPSC rate (Figure 2B), similar to what has been shown in vitro in response to trains of synaptic stimulation (Sargent et al., 2005). Since spillover results from synaptic accumulation of neurotransmitter, a delay would be expected between the peak of the EPSCs and that of the putative spillover current. Indeed, a cross-correlation between the instantaneous frequency of fast EPSCs and the slow currents showed a peak with a lag of 40 ms (Figure 2C), with the slow current lagging the fast events. Similarly, aligning the slow current on a burst of at least 5 EPSCs at 200 Hz or above exhibited a negative peak at positive delay (31 ms latency; 729 bursts from the 9 cells, Figure 2D). We further plotted the synaptic charge transfer over 100 ms as a function of EPSC rate with and without spillover (Figure 2—figure supplement 1). The spillover dramatically affects the slope of this curve.

Bottom Line: Here, we use in vivo patch-clamp recordings to show that locomotion can be directly read out from mossy fiber synaptic input and spike output in single granule cells.The increase in granule cell spiking during locomotion is enhanced by glutamate spillover currents recruited during movement.Thus, synaptic input delivers remarkably rich information to single neurons during locomotion.

View Article: PubMed Central - PubMed

Affiliation: Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.

ABSTRACT
The cerebellum plays a crucial role in the regulation of locomotion, but how movement is represented at the synaptic level is not known. Here, we use in vivo patch-clamp recordings to show that locomotion can be directly read out from mossy fiber synaptic input and spike output in single granule cells. The increase in granule cell spiking during locomotion is enhanced by glutamate spillover currents recruited during movement. Surprisingly, the entire step sequence can be predicted from input EPSCs and output spikes of a single granule cell, suggesting that a robust gait code is present already at the cerebellar input layer and transmitted via the granule cell pathway to downstream Purkinje cells. Thus, synaptic input delivers remarkably rich information to single neurons during locomotion.

No MeSH data available.


Related in: MedlinePlus