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A new measure for the strength of electrical synapses.

Haas JS - Front Cell Neurosci (2015)

Bottom Line: Electrical synapses are typically quantified by subthreshold measurements of coupling, which fall short in describing their impact on spiking activity in coupled neighbors.This method, also applicable to neurotransmitter-based synapses, communicates the considerable strength of electrical synapses.For electrical synapses measured in rodent slices of the thalamic reticular nucleus and in simple model neurons, spike timing is modulated by tens of ms by activity in a coupled neighbor.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Lehigh University Bethlehem, PA, USA.

ABSTRACT
Electrical synapses, like chemical synapses, mediate intraneuronal communication. Electrical synapses are typically quantified by subthreshold measurements of coupling, which fall short in describing their impact on spiking activity in coupled neighbors. Here, we describe a novel measurement for electrical synapse strength that directly evaluates the effect of synaptically transmitted activity on spike timing. This method, also applicable to neurotransmitter-based synapses, communicates the considerable strength of electrical synapses. For electrical synapses measured in rodent slices of the thalamic reticular nucleus and in simple model neurons, spike timing is modulated by tens of ms by activity in a coupled neighbor.

No MeSH data available.


Related in: MedlinePlus

Subthreshold and suprathreshold measurements for the strength of an electrical synapse. (A) Coupling measured with current pulses. Coupling coefficients are a ratio of voltage deflections. Here, voltage deflections were initiated by a step in current delivered in one neuron (gray) that echoed in the coupled neuron (black). cc = 0.17 for the pair shown. Scale bar 1 mV, 50 ms. (B) Coupling coefficient measured by spike and spikelet amplitudes. Spikes were elicited in one neuron (gray) and spikelets in the coupled neighbor (black). Scale bar 2.5 mV (black,) 25 mV (gray), 25 ms. (C) Coupling coefficient measured by burst and burstlet amplitudes, for a longer burst event in one neuron (gray) and a burstlet in the coupled neighbor (black). Scale bar 2.5 mV (black), 25 mV (gray), 25 ms. (D) Coupling measured by latency changes. Modulation of spike latency δL was measured by comparing timing of spikes elicited in one cell alone (black; gray cell quiet), and with the coupled neighbor also driven to spike (gray). Scale bar 2 mV (gray), 20 mV (black), 25 ms. All data presented are from the same pair.
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Figure 1: Subthreshold and suprathreshold measurements for the strength of an electrical synapse. (A) Coupling measured with current pulses. Coupling coefficients are a ratio of voltage deflections. Here, voltage deflections were initiated by a step in current delivered in one neuron (gray) that echoed in the coupled neuron (black). cc = 0.17 for the pair shown. Scale bar 1 mV, 50 ms. (B) Coupling coefficient measured by spike and spikelet amplitudes. Spikes were elicited in one neuron (gray) and spikelets in the coupled neighbor (black). Scale bar 2.5 mV (black,) 25 mV (gray), 25 ms. (C) Coupling coefficient measured by burst and burstlet amplitudes, for a longer burst event in one neuron (gray) and a burstlet in the coupled neighbor (black). Scale bar 2.5 mV (black), 25 mV (gray), 25 ms. (D) Coupling measured by latency changes. Modulation of spike latency δL was measured by comparing timing of spikes elicited in one cell alone (black; gray cell quiet), and with the coupled neighbor also driven to spike (gray). Scale bar 2 mV (gray), 20 mV (black), 25 ms. All data presented are from the same pair.

Mentions: The strength of electrical synapses between gap junction-coupled neurons has traditionally been measured by the coupling coefficient (Bennett, 1966), which is the ratio of a steady, small voltage deflection transmitted from one cell to its neighbor across the synapse (Figure 1A). From the coupling coefficient, one can estimate the conductance of the synapse (Bennett, 1966; Fortier, 2010). Across the brain, average coupling coefficients measured from soma to soma vary from small (<0.05) in inferior olive (Devor and Yarom, 2002) and hippocampus (Zsiros and Maccaferri, 2005); to moderate, 0.1–0.15, in the thalamic reticular nucleus (Landisman et al., 2002) and cortex (Gibson et al., 1999); to even larger values, 0.2 in MesV (Curti et al., 2012). Coupling coefficients for physiological signals such as spikelets (Galarreta and Hestrin, 2001; Haas and Landisman, 2012) have been measured (Figures 1B,C), but are typically smaller than those measured for steady voltage deflections, due to their faster timecourses.


A new measure for the strength of electrical synapses.

Haas JS - Front Cell Neurosci (2015)

Subthreshold and suprathreshold measurements for the strength of an electrical synapse. (A) Coupling measured with current pulses. Coupling coefficients are a ratio of voltage deflections. Here, voltage deflections were initiated by a step in current delivered in one neuron (gray) that echoed in the coupled neuron (black). cc = 0.17 for the pair shown. Scale bar 1 mV, 50 ms. (B) Coupling coefficient measured by spike and spikelet amplitudes. Spikes were elicited in one neuron (gray) and spikelets in the coupled neighbor (black). Scale bar 2.5 mV (black,) 25 mV (gray), 25 ms. (C) Coupling coefficient measured by burst and burstlet amplitudes, for a longer burst event in one neuron (gray) and a burstlet in the coupled neighbor (black). Scale bar 2.5 mV (black), 25 mV (gray), 25 ms. (D) Coupling measured by latency changes. Modulation of spike latency δL was measured by comparing timing of spikes elicited in one cell alone (black; gray cell quiet), and with the coupled neighbor also driven to spike (gray). Scale bar 2 mV (gray), 20 mV (black), 25 ms. All data presented are from the same pair.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585165&req=5

Figure 1: Subthreshold and suprathreshold measurements for the strength of an electrical synapse. (A) Coupling measured with current pulses. Coupling coefficients are a ratio of voltage deflections. Here, voltage deflections were initiated by a step in current delivered in one neuron (gray) that echoed in the coupled neuron (black). cc = 0.17 for the pair shown. Scale bar 1 mV, 50 ms. (B) Coupling coefficient measured by spike and spikelet amplitudes. Spikes were elicited in one neuron (gray) and spikelets in the coupled neighbor (black). Scale bar 2.5 mV (black,) 25 mV (gray), 25 ms. (C) Coupling coefficient measured by burst and burstlet amplitudes, for a longer burst event in one neuron (gray) and a burstlet in the coupled neighbor (black). Scale bar 2.5 mV (black), 25 mV (gray), 25 ms. (D) Coupling measured by latency changes. Modulation of spike latency δL was measured by comparing timing of spikes elicited in one cell alone (black; gray cell quiet), and with the coupled neighbor also driven to spike (gray). Scale bar 2 mV (gray), 20 mV (black), 25 ms. All data presented are from the same pair.
Mentions: The strength of electrical synapses between gap junction-coupled neurons has traditionally been measured by the coupling coefficient (Bennett, 1966), which is the ratio of a steady, small voltage deflection transmitted from one cell to its neighbor across the synapse (Figure 1A). From the coupling coefficient, one can estimate the conductance of the synapse (Bennett, 1966; Fortier, 2010). Across the brain, average coupling coefficients measured from soma to soma vary from small (<0.05) in inferior olive (Devor and Yarom, 2002) and hippocampus (Zsiros and Maccaferri, 2005); to moderate, 0.1–0.15, in the thalamic reticular nucleus (Landisman et al., 2002) and cortex (Gibson et al., 1999); to even larger values, 0.2 in MesV (Curti et al., 2012). Coupling coefficients for physiological signals such as spikelets (Galarreta and Hestrin, 2001; Haas and Landisman, 2012) have been measured (Figures 1B,C), but are typically smaller than those measured for steady voltage deflections, due to their faster timecourses.

Bottom Line: Electrical synapses are typically quantified by subthreshold measurements of coupling, which fall short in describing their impact on spiking activity in coupled neighbors.This method, also applicable to neurotransmitter-based synapses, communicates the considerable strength of electrical synapses.For electrical synapses measured in rodent slices of the thalamic reticular nucleus and in simple model neurons, spike timing is modulated by tens of ms by activity in a coupled neighbor.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Lehigh University Bethlehem, PA, USA.

ABSTRACT
Electrical synapses, like chemical synapses, mediate intraneuronal communication. Electrical synapses are typically quantified by subthreshold measurements of coupling, which fall short in describing their impact on spiking activity in coupled neighbors. Here, we describe a novel measurement for electrical synapse strength that directly evaluates the effect of synaptically transmitted activity on spike timing. This method, also applicable to neurotransmitter-based synapses, communicates the considerable strength of electrical synapses. For electrical synapses measured in rodent slices of the thalamic reticular nucleus and in simple model neurons, spike timing is modulated by tens of ms by activity in a coupled neighbor.

No MeSH data available.


Related in: MedlinePlus