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Delay-Dependent Response in Weakly Electric Fish under Closed-Loop Pulse Stimulation.

Forlim CG, Pinto RD, Varona P, Rodríguez FB - PLoS ONE (2015)

Bottom Line: In this paper, we apply a real time activity-dependent protocol to study how freely swimming weakly electric fish produce and process the timing of their own electric signals.Specifically, we address this study in the elephant fish, Gnathonemus petersii, an animal that uses weak discharges to locate obstacles or food while navigating, as well as for electro-communication with conspecifics.We also discuss the implications of these findings in the context of information processing in weakly electric fish.

View Article: PubMed Central - PubMed

Affiliation: Laboratório Fenômenos Não-Lineares, Instituto de Física, Universidade de São Paulo, São Paulo, Brazil.

ABSTRACT
In this paper, we apply a real time activity-dependent protocol to study how freely swimming weakly electric fish produce and process the timing of their own electric signals. Specifically, we address this study in the elephant fish, Gnathonemus petersii, an animal that uses weak discharges to locate obstacles or food while navigating, as well as for electro-communication with conspecifics. To investigate how the inter pulse intervals vary in response to external stimuli, we compare the response to a simple closed-loop stimulation protocol and the signals generated without electrical stimulation. The activity-dependent stimulation protocol explores different stimulus delivery delays relative to the fish's own electric discharges. We show that there is a critical time delay in this closed-loop interaction, as the largest changes in inter pulse intervals occur when the stimulation delay is below 100 ms. We also discuss the implications of these findings in the context of information processing in weakly electric fish.

No MeSH data available.


Global IPI changes differences for 2 clusters.Mean simple IPI differences between control (X) and stimulus sessions (Y). For the 11 experiments in each cluster in Fig 4, we calculated individually the Tukey mean-difference (Y-X), took the average integrating them in steps of 3 ms and the mean standard deviation (error bars). For cluster A (blue circles), time delays < 100 ms, IPIs discharged during the stimulus sessions were, in average, 90.8 ms shorter than those of the control sessions (blue line), average IPIs from 187 ms to 235 ms presented maximum differences. For cluster B (red triangles), time delays > 100 ms, IPIs discharged during the stimulus sessions were, in average, 3 ms shorter than those of the control sessions (red line). IPIs from 118 ms to 151 ms and from 199 ms to 319 ms were not altered by delays above 100 ms, although IPIs in the last interval had large deviations from the mean. The maximum change in IPIs happened in a range from 157 ms to 196 ms, where fish fired IPIs ~36 ms shorter in the stimulus sessions compared to those in the control sessions. Fish discharged longer IPIs during the stimulus sessions in the IPI ranges from 322 ms to 376 ms. IPIs up to 25 ms were altered independently of time delay.
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pone.0141007.g005: Global IPI changes differences for 2 clusters.Mean simple IPI differences between control (X) and stimulus sessions (Y). For the 11 experiments in each cluster in Fig 4, we calculated individually the Tukey mean-difference (Y-X), took the average integrating them in steps of 3 ms and the mean standard deviation (error bars). For cluster A (blue circles), time delays < 100 ms, IPIs discharged during the stimulus sessions were, in average, 90.8 ms shorter than those of the control sessions (blue line), average IPIs from 187 ms to 235 ms presented maximum differences. For cluster B (red triangles), time delays > 100 ms, IPIs discharged during the stimulus sessions were, in average, 3 ms shorter than those of the control sessions (red line). IPIs from 118 ms to 151 ms and from 199 ms to 319 ms were not altered by delays above 100 ms, although IPIs in the last interval had large deviations from the mean. The maximum change in IPIs happened in a range from 157 ms to 196 ms, where fish fired IPIs ~36 ms shorter in the stimulus sessions compared to those in the control sessions. Fish discharged longer IPIs during the stimulus sessions in the IPI ranges from 322 ms to 376 ms. IPIs up to 25 ms were altered independently of time delay.

Mentions: To further analyze the impact of the closed-loop stimulation on the behavior of fish's EOD, we divided the 22 experiments into 2 clusters, one with datasets from experiments with delays shorter than 100 ms (cluster A) and other with the datasets from delays longer than 100ms (cluster B). For this analysis we used the Tukey mean-difference (Y-X) [35], which accounts for the simple differences between control session IPIs (X) and the stimulation session ones (Y), and computed the average for each cluster (Fig 5 –cluster A–blue circles and cluster B–red circles) and mean standard deviation (error bars in Fig 5). This figure shows the average changes in the IPIs discharged during the closed-loop stimulation sessions as compared to the IPIs discharged during the control sessions. The Tukey mean-difference [35] is the difference between the 2 data sets (Y-X) and it is calculated for each point in the quantile-quantile plot. If the stimulus does not alter the fish's EODs, the sets X and Y will be very similar and, the Tukey mean-difference values will be close to 0. If the data lie on the zero line, it means that there were no changes in IPIs due to the closed-loop stimuli.


Delay-Dependent Response in Weakly Electric Fish under Closed-Loop Pulse Stimulation.

Forlim CG, Pinto RD, Varona P, Rodríguez FB - PLoS ONE (2015)

Global IPI changes differences for 2 clusters.Mean simple IPI differences between control (X) and stimulus sessions (Y). For the 11 experiments in each cluster in Fig 4, we calculated individually the Tukey mean-difference (Y-X), took the average integrating them in steps of 3 ms and the mean standard deviation (error bars). For cluster A (blue circles), time delays < 100 ms, IPIs discharged during the stimulus sessions were, in average, 90.8 ms shorter than those of the control sessions (blue line), average IPIs from 187 ms to 235 ms presented maximum differences. For cluster B (red triangles), time delays > 100 ms, IPIs discharged during the stimulus sessions were, in average, 3 ms shorter than those of the control sessions (red line). IPIs from 118 ms to 151 ms and from 199 ms to 319 ms were not altered by delays above 100 ms, although IPIs in the last interval had large deviations from the mean. The maximum change in IPIs happened in a range from 157 ms to 196 ms, where fish fired IPIs ~36 ms shorter in the stimulus sessions compared to those in the control sessions. Fish discharged longer IPIs during the stimulus sessions in the IPI ranges from 322 ms to 376 ms. IPIs up to 25 ms were altered independently of time delay.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4608794&req=5

pone.0141007.g005: Global IPI changes differences for 2 clusters.Mean simple IPI differences between control (X) and stimulus sessions (Y). For the 11 experiments in each cluster in Fig 4, we calculated individually the Tukey mean-difference (Y-X), took the average integrating them in steps of 3 ms and the mean standard deviation (error bars). For cluster A (blue circles), time delays < 100 ms, IPIs discharged during the stimulus sessions were, in average, 90.8 ms shorter than those of the control sessions (blue line), average IPIs from 187 ms to 235 ms presented maximum differences. For cluster B (red triangles), time delays > 100 ms, IPIs discharged during the stimulus sessions were, in average, 3 ms shorter than those of the control sessions (red line). IPIs from 118 ms to 151 ms and from 199 ms to 319 ms were not altered by delays above 100 ms, although IPIs in the last interval had large deviations from the mean. The maximum change in IPIs happened in a range from 157 ms to 196 ms, where fish fired IPIs ~36 ms shorter in the stimulus sessions compared to those in the control sessions. Fish discharged longer IPIs during the stimulus sessions in the IPI ranges from 322 ms to 376 ms. IPIs up to 25 ms were altered independently of time delay.
Mentions: To further analyze the impact of the closed-loop stimulation on the behavior of fish's EOD, we divided the 22 experiments into 2 clusters, one with datasets from experiments with delays shorter than 100 ms (cluster A) and other with the datasets from delays longer than 100ms (cluster B). For this analysis we used the Tukey mean-difference (Y-X) [35], which accounts for the simple differences between control session IPIs (X) and the stimulation session ones (Y), and computed the average for each cluster (Fig 5 –cluster A–blue circles and cluster B–red circles) and mean standard deviation (error bars in Fig 5). This figure shows the average changes in the IPIs discharged during the closed-loop stimulation sessions as compared to the IPIs discharged during the control sessions. The Tukey mean-difference [35] is the difference between the 2 data sets (Y-X) and it is calculated for each point in the quantile-quantile plot. If the stimulus does not alter the fish's EODs, the sets X and Y will be very similar and, the Tukey mean-difference values will be close to 0. If the data lie on the zero line, it means that there were no changes in IPIs due to the closed-loop stimuli.

Bottom Line: In this paper, we apply a real time activity-dependent protocol to study how freely swimming weakly electric fish produce and process the timing of their own electric signals.Specifically, we address this study in the elephant fish, Gnathonemus petersii, an animal that uses weak discharges to locate obstacles or food while navigating, as well as for electro-communication with conspecifics.We also discuss the implications of these findings in the context of information processing in weakly electric fish.

View Article: PubMed Central - PubMed

Affiliation: Laboratório Fenômenos Não-Lineares, Instituto de Física, Universidade de São Paulo, São Paulo, Brazil.

ABSTRACT
In this paper, we apply a real time activity-dependent protocol to study how freely swimming weakly electric fish produce and process the timing of their own electric signals. Specifically, we address this study in the elephant fish, Gnathonemus petersii, an animal that uses weak discharges to locate obstacles or food while navigating, as well as for electro-communication with conspecifics. To investigate how the inter pulse intervals vary in response to external stimuli, we compare the response to a simple closed-loop stimulation protocol and the signals generated without electrical stimulation. The activity-dependent stimulation protocol explores different stimulus delivery delays relative to the fish's own electric discharges. We show that there is a critical time delay in this closed-loop interaction, as the largest changes in inter pulse intervals occur when the stimulation delay is below 100 ms. We also discuss the implications of these findings in the context of information processing in weakly electric fish.

No MeSH data available.