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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.


Fish response depends on the closed-loop stimulus time delay.IPI distributions of 4 different experiments are shown for control (dashed lines) and closed-loop stimulation sessions (solid lines), each panel represents the data of a single fish subjected to a single delay for 30 min, the IPIs used to build the histograms were defined in Fig 1B. Top-left–For the stimulus session with time delay d = 10 ms (full line) fish increased the discharges of shorter IPIs, specially around 60 ms IPIs and decreased the probability of firing longer IPIs (> 300 ms) when compared to those of the control session (dashed line). There were also changes in the overall shape of the IPI distribution (50% Pearson's corr., Kolmogorov-Smirnov (KS) p = 0.004). Bottom-left–When stimulated with pulses with time delay d = 12 ms (solid line), fish shortened its IPIs from 5 ms to 200 ms, that is, there was an increase in the frequency of the electric organ as compared to those for the control session (dashed line). For longer IPIs (>200ms) no changes were observed between control and stimulus sessions, i.e., the shape of the IPI distribution remained the same in both sessions with a shift of ~20 ms (52% Pearson's corr., KS p = 0.07). Top-right–For the time delay d = 102 ms (full line), fish increased the probability of firing shorter IPIs of ~20 ms and also longer IPIs (> 300 ms), and decreased the probability of discharging IPIs around 140 ms as compared to those of the control session (dashed line). There were slight changes in the shape of the IPI distribution (89% Pearson's corr. KS p = 0.8). Bottom-right—For stimulus session with time delay d = 172 ms (solid line), fish discharged with high probability 140 ms IPIs and 300 ms IPIs and the shape of the IPI distribution did not change (97% Pearson's corr. KS p = 0.4).
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pone.0141007.g002: Fish response depends on the closed-loop stimulus time delay.IPI distributions of 4 different experiments are shown for control (dashed lines) and closed-loop stimulation sessions (solid lines), each panel represents the data of a single fish subjected to a single delay for 30 min, the IPIs used to build the histograms were defined in Fig 1B. Top-left–For the stimulus session with time delay d = 10 ms (full line) fish increased the discharges of shorter IPIs, specially around 60 ms IPIs and decreased the probability of firing longer IPIs (> 300 ms) when compared to those of the control session (dashed line). There were also changes in the overall shape of the IPI distribution (50% Pearson's corr., Kolmogorov-Smirnov (KS) p = 0.004). Bottom-left–When stimulated with pulses with time delay d = 12 ms (solid line), fish shortened its IPIs from 5 ms to 200 ms, that is, there was an increase in the frequency of the electric organ as compared to those for the control session (dashed line). For longer IPIs (>200ms) no changes were observed between control and stimulus sessions, i.e., the shape of the IPI distribution remained the same in both sessions with a shift of ~20 ms (52% Pearson's corr., KS p = 0.07). Top-right–For the time delay d = 102 ms (full line), fish increased the probability of firing shorter IPIs of ~20 ms and also longer IPIs (> 300 ms), and decreased the probability of discharging IPIs around 140 ms as compared to those of the control session (dashed line). There were slight changes in the shape of the IPI distribution (89% Pearson's corr. KS p = 0.8). Bottom-right—For stimulus session with time delay d = 172 ms (solid line), fish discharged with high probability 140 ms IPIs and 300 ms IPIs and the shape of the IPI distribution did not change (97% Pearson's corr. KS p = 0.4).

Mentions: Fish reacted differently, increasing/decreasing their IPIs depending on the delay d used to deliver the stimulus. In Fig 2 we show representative examples of 4 experiments where one can observe different IPI responses to different delays as compared to the control sessions: increase of frequency (shorter IPIs) and change in the IPI distribution shape (50% Pearson's corr., kolmogorov-smirnov (KS) p = 0.004; 10 ms delay; Fig 2 –top left), increase in frequency, but no changes in the shape of IPI distribution (52% Pearson's corr., KS p = 0.07; 12 ms delay; Fig 2 –bottom left), slight decrease/increase of frequency changing the shape of distribution (89% Pearson's corr. KS p = 0.8; 102 ms delay; Fig 2 –top right) and slight changes in frequency and similar IPI distributions (97% Pearson's corr. KS p = 0.4; 172 ms delay; Fig 2 –bottom right). Each panel represents the data from a single fish subjected to a single delay for 30 min, the IPIs are shown in Fig 1B.


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

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

Fish response depends on the closed-loop stimulus time delay.IPI distributions of 4 different experiments are shown for control (dashed lines) and closed-loop stimulation sessions (solid lines), each panel represents the data of a single fish subjected to a single delay for 30 min, the IPIs used to build the histograms were defined in Fig 1B. Top-left–For the stimulus session with time delay d = 10 ms (full line) fish increased the discharges of shorter IPIs, specially around 60 ms IPIs and decreased the probability of firing longer IPIs (> 300 ms) when compared to those of the control session (dashed line). There were also changes in the overall shape of the IPI distribution (50% Pearson's corr., Kolmogorov-Smirnov (KS) p = 0.004). Bottom-left–When stimulated with pulses with time delay d = 12 ms (solid line), fish shortened its IPIs from 5 ms to 200 ms, that is, there was an increase in the frequency of the electric organ as compared to those for the control session (dashed line). For longer IPIs (>200ms) no changes were observed between control and stimulus sessions, i.e., the shape of the IPI distribution remained the same in both sessions with a shift of ~20 ms (52% Pearson's corr., KS p = 0.07). Top-right–For the time delay d = 102 ms (full line), fish increased the probability of firing shorter IPIs of ~20 ms and also longer IPIs (> 300 ms), and decreased the probability of discharging IPIs around 140 ms as compared to those of the control session (dashed line). There were slight changes in the shape of the IPI distribution (89% Pearson's corr. KS p = 0.8). Bottom-right—For stimulus session with time delay d = 172 ms (solid line), fish discharged with high probability 140 ms IPIs and 300 ms IPIs and the shape of the IPI distribution did not change (97% Pearson's corr. KS p = 0.4).
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Related In: Results  -  Collection

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pone.0141007.g002: Fish response depends on the closed-loop stimulus time delay.IPI distributions of 4 different experiments are shown for control (dashed lines) and closed-loop stimulation sessions (solid lines), each panel represents the data of a single fish subjected to a single delay for 30 min, the IPIs used to build the histograms were defined in Fig 1B. Top-left–For the stimulus session with time delay d = 10 ms (full line) fish increased the discharges of shorter IPIs, specially around 60 ms IPIs and decreased the probability of firing longer IPIs (> 300 ms) when compared to those of the control session (dashed line). There were also changes in the overall shape of the IPI distribution (50% Pearson's corr., Kolmogorov-Smirnov (KS) p = 0.004). Bottom-left–When stimulated with pulses with time delay d = 12 ms (solid line), fish shortened its IPIs from 5 ms to 200 ms, that is, there was an increase in the frequency of the electric organ as compared to those for the control session (dashed line). For longer IPIs (>200ms) no changes were observed between control and stimulus sessions, i.e., the shape of the IPI distribution remained the same in both sessions with a shift of ~20 ms (52% Pearson's corr., KS p = 0.07). Top-right–For the time delay d = 102 ms (full line), fish increased the probability of firing shorter IPIs of ~20 ms and also longer IPIs (> 300 ms), and decreased the probability of discharging IPIs around 140 ms as compared to those of the control session (dashed line). There were slight changes in the shape of the IPI distribution (89% Pearson's corr. KS p = 0.8). Bottom-right—For stimulus session with time delay d = 172 ms (solid line), fish discharged with high probability 140 ms IPIs and 300 ms IPIs and the shape of the IPI distribution did not change (97% Pearson's corr. KS p = 0.4).
Mentions: Fish reacted differently, increasing/decreasing their IPIs depending on the delay d used to deliver the stimulus. In Fig 2 we show representative examples of 4 experiments where one can observe different IPI responses to different delays as compared to the control sessions: increase of frequency (shorter IPIs) and change in the IPI distribution shape (50% Pearson's corr., kolmogorov-smirnov (KS) p = 0.004; 10 ms delay; Fig 2 –top left), increase in frequency, but no changes in the shape of IPI distribution (52% Pearson's corr., KS p = 0.07; 12 ms delay; Fig 2 –bottom left), slight decrease/increase of frequency changing the shape of distribution (89% Pearson's corr. KS p = 0.8; 102 ms delay; Fig 2 –top right) and slight changes in frequency and similar IPI distributions (97% Pearson's corr. KS p = 0.4; 172 ms delay; Fig 2 –bottom right). Each panel represents the data from a single fish subjected to a single delay for 30 min, the IPIs are shown in Fig 1B.

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.