AutoEPG: Software for the Analysis of Electrical Activity in the Microcircuit Underpinning Feeding Behaviour of Caenorhabditis elegans

Abstract

BackgroundThe pharyngeal microcircuit of the nematode Caenorhabditis elegans serves as a model for analysing neural network activity and is amenable to electrophysiological recording techniques. One such technique is the electropharyngeogram (EPG) which has provided insight into the genetic basis of feeding behaviour, neurotransmission and muscle excitability. However, the detailed manual analysis of the digital recordings necessary to identify subtle differences in activity that reflect modulatory changes within the underlying network is time consuming and low throughput. To address this we have developed an automated system for the high-throughput and discrete analysis of EPG recordings (AutoEPG).Methodology/Principal FindingsAutoEPG employs a tailor made signal processing algorithm that automatically detects different features of the EPG signal including those that report on the relaxation and contraction of the muscle and neuronal activity. Manual verification of the detection algorithm has demonstrated AutoEPG is capable of very high levels of accuracy. We have further validated the software by analysing existing mutant strains with known pharyngeal phenotypes detectable by the EPG. In doing so, we have more precisely defined an evolutionarily conserved role for the calcium-dependent potassium channel, SLO-1, in modulating the rhythmic activity of neural networks.Conclusions/SignificanceAutoEPG enables the consistent analysis of EPG recordings, significantly increases analysis throughput and allows the robust identification of subtle changes in the electrical activity of the pharyngeal nervous system. It is anticipated that AutoEPG will further add to the experimental tractability of the C. elegans pharynx as a model neural circuit.

Selective Toxicity of the Anthelmintic Emodepside Revealed by Heterologous Expression of Human KCNMA1 inCaenorhabditis elegans

“…Thus, although the pattern of pharyngeal pumping in wildtype worms consists of pumps that occur predominantly in groups of 1 to 3, in slo-1(js379), this pattern is disrupted, and pumps occur in larger groups (Dillon et al, 2009). This is consistent with the idea that SLO-1 has a role in regulating the excitability of neural networks and thus, in its absence, the stability of the network activity is disturbed, leading to bursts of activity.…”

“…The pharyngeal preparation was transferred to the recording chamber (volume, ϳ1 ml). EPG recordings were made using methods described previously (Dillon et al, 2009). Recordings were made in the presence of perfusion at a constant rate of 5 ml/min.…”

“…Basal pumping of N2 wild-type C. elegans typically includes pump groups of 1, 2, or 3. In contrast, slo-1(js379) mutants pump mainly in groups of higher than 3, displaying "bursting" pumping (Dillon et al, 2009). To evaluate rescue of this slo-1(js379) pharyngeal phenotype, transgenic C. elegans expressing either slo-1 or kcnma1 behind the native pslo-1 promoter were analyzed for the behavior of pumping in groups using AutoEPG software (Dillon et al, 2009).…”

“…For each experiment, 10-min recording of basal pharyngeal pumping was acquired. This was subjected to analysis with AutoEPG (Dillon et al, 2009), which counted the number of pumps that occurred as single pumps and the number of pumps that occurred in groups of three or more. The data are expressed as the number of pumps that occurred in groups of one to three (open bars) or more than three (hatched bars) as a percentage of the total number of pumps.…”

Chemical activation of a food deprivation signal extends lifespan

“…Briefly, the worms were placed in the device in Dent's solution supplemented with 5 m m 5‐HT (to stimulate pumping) and recorded for 2–5 min. Recorded EPG traces were analyzed using the AutoEPG software (Dillon et al ., 2009), which annotates and compiles individual features of the traces such as P spikes. Two‐way ANOVA within GraphPad Prism ™ software was used to test significance.…”