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Gerhard Von Der Emde - One of the best experts on this subject based on the ideXlab platform.
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Distance and shape: perception of the 3-dimensional world by weakly Electric Fish.
Journal of physiology Paris, 2020Co-Authors: Gerhard Von Der EmdeAbstract:Weakly Electric Fish orient at night in complete darkness by employing their active electrolocation system. They emit short Electric signals and perceive the consequences of these emissions with epidermal electroreceptors. Objects are detected by analyzing the Electric images which they project onto the animal's electroreceptive skin surface. This process corresponds to similar processes during vision, where visual images are cast onto the retinas of eyes. Behavioral experiments have shown that Electric Fish can measure the distance of objects during active electrolocation, thus possessing three-dimensional depth perception of their surroundings. The fundamental mechanism for distance determination differs from stereopsis used during vision by two-eyed animals, but resembles some supplementary mechanisms for distance deduction in humans. Weakly Electric Fish can also perceive the three-dimensional shape of objects. The Fish can learn to identify certain objects and discriminate them from all other objects. In addition, they spontaneously categorize objects according to their shapes and not according to object size or material properties. There is good evidence that some fundamental types of perceptional invariances during visual object recognition in humans are also found in Electric Fish during active electrolocation. These include size invariance (maybe including size constancy), rotational invariance, and translational invariance. The mechanisms of shape detection during electrolocation are still unknown, and their discoveries require additional experiments.
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evidence for mutual allocation of social attention through interactive signaling in a mormyrid weakly Electric Fish
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Martin Worm, Frank Kirschbaum, Tim Landgraf, Hai Nguyen, Julia Prume, Gerhard Von Der EmdeAbstract:Mormyrid weakly Electric Fish produce Electric organ discharges (EODs) for active electrolocation and electrocommunication. These pulses are emitted with variable interdischarge intervals (IDIs) resulting in temporal discharge patterns and interactive signaling episodes with nearby conspecifics. However, unequivocal assignment of interactive signaling to a specific behavioral context has proven to be challenging. Using an ethorobotical approach, we confronted single individuals of weakly Electric Mormyrus rume proboscirostris with a mobile Fish robot capable of interacting both physically, on arbitrary trajectories, as well as Electrically, by generating echo responses through playback of species-specific EODs, thus synchronizing signals with the Fish. Interactive signaling by the Fish was more pronounced in response to a dynamic echo playback generated by the robot than in response to playback of static random IDI sequences. Such synchronizations were particularly strong at a distance corresponding to the outer limit of active electrolocation, and when Fish oriented toward the Fish replica. We therefore argue that interactive signaling through echoing of a conspecific’s EODs provides a simple mechanism by which weakly Electric Fish can specifically address nearby individuals during electrocommunication. Echoing may thus enable mormyrids to mutually allocate social attention and constitute a foundation for complex social behavior and relatively advanced cognitive abilities in a basal vertebrate lineage.
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social interactions between live and artificial weakly Electric Fish electrocommunication and locomotor behavior of mormyrus rume proboscirostris towards a mobile dummy Fish
PLOS ONE, 2017Co-Authors: Martin Worm, Frank Kirschbaum, Gerhard Von Der EmdeAbstract:Mormyrid weakly Electric Fish produce short, pulse-type Electric organ discharges for actively probing their environment and to communicate with conspecifics. Animals emit sequences of pulse-trains that vary in overall frequency and temporal patterning and can lead to time-locked interactions with the discharge activity of other individuals. Both active electrolocation and electrocommunication are additionally accompanied by stereotypical locomotor patterns. However, the concrete roles of Electrical and locomotor patterns during social interactions in mormyrids are not well understood. Here we used a mobile Fish dummy that was emitting different types of Electrical playback sequences to study following behavior and interaction patterns (Electrical and locomotor) between individuals of weakly Electric Fish. We confronted single individuals of Mormyrus rume proboscirostris with a mobile dummy Fish designed to attract Fish from a shelter and recruit them into an open area by emitting Electrical playbacks of natural discharge sequences. We found that Fish were reliably recruited by the mobile dummy if it emitted Electrical signals and followed it largely independently of the presented playback patterns. While following the dummy, Fish interacted with it spatially by displaying stereotypical motor patterns, as well as Electrically, e.g. through discharge regularizations and by synchronizing their own discharge activity to the playback. However, the overall emission frequencies of the dummy were not adopted by the following Fish. Instead, social signals based on different temporal patterns were emitted depending on the type of playback. In particular, double pulses were displayed in response to Electrical signaling of the dummy and their expression was positively correlated with an animals' rank in the dominance hierarchy. Based on additional analysis of swimming trajectories and stereotypical locomotor behavior patterns, we conclude that the reception and emission of Electrical communication signals play a crucial role in mediating social interactions in mormyrid weakly Electric Fish.
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investigation of collective behaviour and electrocommunication in the weakly Electric Fish mormyrus rume through a biomimetic robotic dummy Fish
Bioinspiration & Biomimetics, 2016Co-Authors: Elisa Donati, Gerhard Von Der Emde, Martin Worm, Stefano Mintchev, Marleen Van Der Wiel, Giovanni Benelli, Cesare StefaniniAbstract:A robotic Fish has been developed to create a mixed bio-hybrid system made up of weakly Electric Fish and a mobile dummy Fish. Weakly Electric Fish are capable of interacting with each other via sequences of self-generated Electric signals during electrocommunication. Here we present the design of an artificial dummy Fish, which is subsequently tested in behavioural experiments. The robot consists of two parts: a flexible tail that can move at different frequencies and amplitudes, performing a carangiform oscillation, and a rigid head containing the motor for the tail oscillation. The dummy Fish mimics the weakly Electric Fish Mormyrus rume in morphology, size and Electric signal generation. In order to study Electrical interactions, the dummy Fish is equipped with ten electrodes that record Electric signals of nearby real Fish and generate Electric dipole fields around itself that are similar to those produced by real Fish in both waveform and sequence. Behavioural experiments demonstrate that the dummy Fish is able to recruit both single individuals and groups of M. rume from a shelter into an exposed area. The development of an artificial dummy Fish may help to understand fundamental aspects of collective behaviour in weakly Electric Fish and the properties necessary to initiate and sustain it in closed-loop feedback experiments based on electrocommunication.
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Living Machines - Electro-communicating Dummy Fish Initiate Group Behavior in the Weakly Electric Fish Mormyrus rume
Biomimetic and Biohybrid Systems, 2014Co-Authors: Martin Worm, Tim Landgraf, Hai Nguyen, Gerhard Von Der EmdeAbstract:The mechanisms that underlie collective behavior in groups of Fish have been the subject of numerous quantitative and theoretical studies. We use a robotic platform to investigate social interactions in weakly Electric Fish by exploiting their unique electro-sensory modality for animal-robot communication. Our results demonstrate that weakly Electric Fish interact with a mobile dummy Fish based on species-specific Electrical playback signals and are therefore proposed to be a promising model organism for establishing a mixed-society of real and artificial Fish.
Maurice J Chacron - One of the best experts on this subject based on the ideXlab platform.
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electrosensory processing in apteronotus albifrons implications for general and specific neural coding strategies across wave type weakly Electric Fish species
Journal of Neurophysiology, 2016Co-Authors: Diana Martinez, Michael G Metzen, Maurice J ChacronAbstract:To understand the general principles by which the brain processes sensory input thereby giving rise to behavior, it is often advantageous to compare results obtained across multiple species. Here we examined hindbrain pyramidal neuron responses in the weakly Electric Fish Apteronotus albifrons. While our results show that pyramidal neurons in A. albifrons display electrophysiological properties that are similar to those of other wave-type species, there were some important differences.
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neural correlations enable invariant coding and perception of natural stimuli in weakly Electric Fish
eLife, 2016Co-Authors: Michael G Metzen, Volker Hofmann, Maurice J ChacronAbstract:We can effortlessly recognize an object – a car, for example – in many different contexts such as when seen from behind, under different lighting levels or even from different viewpoints. This phenomenon is known as perceptual invariance: objects are correctly recognized, despite variations in exactly what is seen (or otherwise sensed). However, it is still not clear how the brain processes perceptual information to recognize the same object under a wide variety of contexts. Some Fish, such as the brown ghost knifeFish, produce a weak Electric signal that they can alter to communicate with other members of their species. A communication call may be produced in a variety of contexts that alter which aspects of the signal nearby Fish detect. Despite this, Fish tend to respond to a given communication call in the same way regardless of its context; this suggests that these Fish also have perceptual invariance. The communication calls of weakly Electric Fish can be easily mimicked in a laboratory and produce reliable behavioral responses, which makes these Fish a good model for understanding how perceptual invariance might be coded in the brain. Therefore, Metzen et al. recorded the activity of the receptor neurons that first respond to communication calls in weakly Electric Fish. The results revealed that a given communication signal made the firing patterns of all receptor neurons in the Fish’s brain more similar to each other, regardless of the signal’s context. This occurs despite the changes in context causing single receptor neurons to respond in different ways. At each stage of the process by which information is transmitted from the receptor neurons to neurons deeper in the brain, the similarity in the neurons’ firing patterns is refined, thereby giving rise to perceptual invariance. While perceptual invariance to a given object in different contexts is desirable, it is also important to be able to distinguish between different objects. This implies that neurons should respond similarly to stimuli associated with the same object and differently to stimuli associated with different objects. Further studies are now needed to confirm whether this is the case.
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weakly Electric Fish display behavioral responses to envelopes naturally occurring during movement implications for neural processing
The Journal of Experimental Biology, 2014Co-Authors: Michael G Metzen, Maurice J ChacronAbstract:How the brain processes natural sensory input remains an important and poorly understood problem in neuroscience. The efficient coding hypothesis asserts that the brain’s coding strategies are adapted to the statistics of natural stimuli in order to efficiently process them, thereby optimizing their perception by the organism. Here we examined whether gymnotiform weakly Electric Fish displayed behavioral responses that are adapted to the statistics of the natural electrosensory envelopes. Previous studies have shown that the envelopes resulting from movement tend to consist of low ( 1 Hz) temporal frequencies that can thus mask more behaviorally relevant signals. We found that the self-generated Electric organ discharge frequency follows the detailed time course of the envelope around a mean value that is positively offset with respect to its baseline value for temporal frequencies between 0.001 Hz and 1 Hz. The frequency-following component of this behavioral response decreased in magnitude as a power law as a function of the envelope frequency and was negligible for envelope frequencies above 1 Hz. In contrast, the offset component was relatively constant and somewhat increased for envelope frequencies above 1 Hz. Thus, our results show that weakly Electric Fish display behavioral responses that track the detailed time course of low but not high frequency envelope stimuli. Furthermore, we found that the magnitude of the frequency-following behavioral response matches, in a one-to-one fashion, the spectral power of natural second-order stimulus attributes observed during movement. Indeed, both decayed as a power law with the same exponent for temporal frequencies spanning three orders of magnitude. Thus, our findings suggest that the neural coding strategies used by weakly Electric Fish perceive the detailed time course of movement envelopes and are adapted to their statistics as found in the natural environment. They also suggest that weakly Electric Fish might take advantage of the differential frequency content of movement and social envelopes in order to give appropriate behavioral responses during encounters between two or more conspecifics.
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neuromodulation of early electrosensory processing in gymnotiform weakly Electric Fish
The Journal of Experimental Biology, 2013Co-Authors: Brenda Toscano Marquez, Rüdiger Krahe, Maurice J ChacronAbstract:Sensory neurons continually adapt their processing properties in response to changes in the sensory environment or the brain's internal state. Neuromodulators are thought to mediate such adaptation through a variety of receptors and their action has been implicated in processes such as attention, learning and memory, aggression, reproductive behaviour and state-dependent mechanisms. Here, we review recent work on neuromodulation of electrosensory processing by acetylcholine and serotonin in the weakly Electric Fish Apteronotus leptorhynchus . Specifically, our review focuses on how experimental application of these neuromodulators alters excitability and responses to sensory input of pyramidal cells within the hindbrain electrosensory lateral line lobe. We then discuss current hypotheses on the functional roles of these two neuromodulatory pathways in regulating electrosensory processing at the organismal level and the need for identifying the natural behavioural conditions that activate these pathways. * Abbreviations: 4-AP : 4-aminopyridine 5-HT : serotonin ACh : acetylcholine AHP : afterhyperpolarization CLS : centrolateral segment CMS : centromedial segment EGp : eminentia granularis posterior ELL : electrosensory lateral line lobe EOD : Electric organ discharge LS : lateral segment Pd : nucleus praeeminentialis dorsalis SK : small-conductance calcium-activated potassium (channel) TSd : torus semicircularis dorsalis
Andre Longtin - One of the best experts on this subject based on the ideXlab platform.
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active sensing associated with spatial learning reveals memory based attention in an Electric Fish
Journal of Neurophysiology, 2016Co-Authors: Andre Longtin, Leonard MalerAbstract:Active sensing behaviors reveal what an animal is attending to and how it changes with learning. Gymnotus sp., a gymnotiform weakly Electric Fish, generates an Electric organ discharge (EOD) as dis...
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enhanced sensory sampling precedes self initiated locomotion in an Electric Fish
The Journal of Experimental Biology, 2014Co-Authors: Andre Longtin, Leonard MalerAbstract:Cortical activity precedes self-initiated movements by several seconds in mammals; this observation has led into inquiries on the nature of volition. Preparatory neural activity is known to be associated with decision making and movement planning. Self-initiated locomotion has been linked to increased active sensory sampling; however, the precise temporal relationship between sensory acquisition and voluntary movement initiation has not been established. Based on long-term monitoring of sensory sampling activity that is readily observable in freely behaving pulse-type Electric Fish, we show that heightened sensory acquisition precedes spontaneous initiation of swimming. Gymnotus sp. revealed a bimodal distribution of Electric organ discharge rate (EODR) demonstrating down- and up-states of sensory sampling and neural activity; movements only occurred during up-states and up-states were initiated before movement onset. EODR during voluntary swimming initiation exhibited greater trial-to-trial variability than the sound-evoked increases in EODR. The sampling variability declined after voluntary movement onset as previously observed for the neural variability associated with decision making in primates. Spontaneous movements occurred randomly without a characteristic timescale, and no significant temporal correlation was found between successive movement intervals. Using statistical analyses of spontaneous exploratory behaviours and associated preparatory sensory sampling increase, we conclude that Electric Fish exhibit key attributes of volitional movements, and that voluntary behaviours in vertebrates may generally be preceded by increased sensory sampling. Our results suggest that comparative studies of the neural basis of volition may therefore be possible in pulse-type Electric Fish, given the substantial homologies between the telencephali of teleost Fish and mammals.
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cellular and circuit properties supporting different sensory coding strategies in Electric Fish and other systems
Current Opinion in Neurobiology, 2012Co-Authors: Gary Marsat, Andre Longtin, Leonard MalerAbstract:Neural codes often seem tailored to the type of information they must carry. Here we contrast the encoding strategies for two different communication signals in Electric Fish and describe the underlying cellular and network properties that implement them. We compare an aggressive signal that needs to be quickly detected, to a courtship signal whose quality needs to be evaluated. The aggressive signal is encoded by synchronized bursts and a predictive feedback input is crucial in separating background noise from the communication signal. The courtship signal is accurately encoded through a heterogenous population response allowing the discrimination of signal differences. Most importantly we show that the same strategies are used in other systems arguing that they evolved similar solutions because they faced similar tasks.
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Signal cancellation in neural systems: encoding sensory input in the weakly Electric Fish
2012 11th International Conference on Information Science Signal Processing and their Applications (ISSPA), 2012Co-Authors: Gary Marsat, Leonard Maler, Jorge F. Mejias, Erik Harvey-girard, Andre LongtinAbstract:We present a biologically plausible mechanism to cancel simple redundant signals, i.e. sinusoidal waves, in neural circuits. Our mechanism involves the presence of: 1) stimulus-driven feedback to the neurons acting as detectors, 2) a large variety of temporal delays in the pathways transmitting such feedback, and 3) burst-induced long-term plasticity, all these factors being present in a wide set of neural systems. As an example, we consider the electrosensory lateral-line lobe of the weakly Electric Fish, which has been recently reported to employ this mechanism for the cancellation of redundant information in vivo. The cancellation is shown to be maintained for signals with different strengths of amplitude modulations.
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spatial acuity and prey detection in weakly Electric Fish
PLOS Computational Biology, 2007Co-Authors: David Babineau, John E Lewis, Andre LongtinAbstract:It is well-known that weakly Electric Fish can exhibit extreme temporal acuity at the behavioral level, discriminating time intervals in the submicrosecond range. However, relatively little is known about the spatial acuity of the electrosense. Here we use a recently developed model of the Electric field generated by Apteronotus leptorhynchus to study spatial acuity and small signal extraction. We show that the quality of sensory information available on the lateral body surface is highest for objects close to the Fish's midbody, suggesting that spatial acuity should be highest at this location. Overall, however, this information is relatively blurry and the electrosense exhibits relatively poor acuity. Despite this apparent limitation, weakly Electric Fish are able to extract the minute signals generated by small prey, even in the presence of large background signals. In fact, we show that the Fish's poor spatial acuity may actually enhance prey detection under some conditions. This occurs because the Electric image produced by a spatially dense background is relatively “blurred” or spatially uniform. Hence, the small spatially localized prey signal “pops out” when Fish motion is simulated. This shows explicitly how the back-and-forth swimming, characteristic of these Fish, can be used to generate motion cues that, as in other animals, assist in the extraction of sensory information when signal-to-noise ratios are low. Our study also reveals the importance of the structure of complex electrosensory backgrounds. Whereas large-object spacing is favorable for discriminating the individual elements of a scene, small spacing can increase the Fish's ability to resolve a single target object against this background.
Cesare Stefanini - One of the best experts on this subject based on the ideXlab platform.
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investigation of collective behaviour and electrocommunication in the weakly Electric Fish mormyrus rume through a biomimetic robotic dummy Fish
Bioinspiration & Biomimetics, 2016Co-Authors: Elisa Donati, Gerhard Von Der Emde, Martin Worm, Stefano Mintchev, Marleen Van Der Wiel, Giovanni Benelli, Cesare StefaniniAbstract:A robotic Fish has been developed to create a mixed bio-hybrid system made up of weakly Electric Fish and a mobile dummy Fish. Weakly Electric Fish are capable of interacting with each other via sequences of self-generated Electric signals during electrocommunication. Here we present the design of an artificial dummy Fish, which is subsequently tested in behavioural experiments. The robot consists of two parts: a flexible tail that can move at different frequencies and amplitudes, performing a carangiform oscillation, and a rigid head containing the motor for the tail oscillation. The dummy Fish mimics the weakly Electric Fish Mormyrus rume in morphology, size and Electric signal generation. In order to study Electrical interactions, the dummy Fish is equipped with ten electrodes that record Electric signals of nearby real Fish and generate Electric dipole fields around itself that are similar to those produced by real Fish in both waveform and sequence. Behavioural experiments demonstrate that the dummy Fish is able to recruit both single individuals and groups of M. rume from a shelter into an exposed area. The development of an artificial dummy Fish may help to understand fundamental aspects of collective behaviour in weakly Electric Fish and the properties necessary to initiate and sustain it in closed-loop feedback experiments based on electrocommunication.
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Electrolocation Sensors in Conducting Water Bio-Inspired by Electric Fish
IEEE Sensors Journal, 2013Co-Authors: Noël Servagent, Cesare Stefanini, Brahim Jawad, Stéphane Bouvier, Frédéric Boyer, Alexis Girin, Francesco Gomez, Vincent Lebastard, Pol-bernard GossiauxAbstract:This article presents the first research into designing an active sensor inspired by Electric Fish. It is notable for its potential for robotics underwater navigation and exploration tasks in conditions where vision and sonar would meet difficulty. It could also be used as a complementary omnidirectional, short range sense to vision and sonar. Combined with a well defined engine geometry, this sensor can be modeled analytically. In this article, we focus on a particular measurement mode where one electrode of the sensor acts as a current emitter and the others as current receivers. In spite of the high sensitivity required by Electric sense, the first results show that we can obtain a detection range of the order of the sensor length, which suggests that this sensor principle can be used for robotics obstacle avoidance as it is illustrated at the end of the article.
Leonard Maler - One of the best experts on this subject based on the ideXlab platform.
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active sensing associated with spatial learning reveals memory based attention in an Electric Fish
Journal of Neurophysiology, 2016Co-Authors: Andre Longtin, Leonard MalerAbstract:Active sensing behaviors reveal what an animal is attending to and how it changes with learning. Gymnotus sp., a gymnotiform weakly Electric Fish, generates an Electric organ discharge (EOD) as dis...
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enhanced sensory sampling precedes self initiated locomotion in an Electric Fish
The Journal of Experimental Biology, 2014Co-Authors: Andre Longtin, Leonard MalerAbstract:Cortical activity precedes self-initiated movements by several seconds in mammals; this observation has led into inquiries on the nature of volition. Preparatory neural activity is known to be associated with decision making and movement planning. Self-initiated locomotion has been linked to increased active sensory sampling; however, the precise temporal relationship between sensory acquisition and voluntary movement initiation has not been established. Based on long-term monitoring of sensory sampling activity that is readily observable in freely behaving pulse-type Electric Fish, we show that heightened sensory acquisition precedes spontaneous initiation of swimming. Gymnotus sp. revealed a bimodal distribution of Electric organ discharge rate (EODR) demonstrating down- and up-states of sensory sampling and neural activity; movements only occurred during up-states and up-states were initiated before movement onset. EODR during voluntary swimming initiation exhibited greater trial-to-trial variability than the sound-evoked increases in EODR. The sampling variability declined after voluntary movement onset as previously observed for the neural variability associated with decision making in primates. Spontaneous movements occurred randomly without a characteristic timescale, and no significant temporal correlation was found between successive movement intervals. Using statistical analyses of spontaneous exploratory behaviours and associated preparatory sensory sampling increase, we conclude that Electric Fish exhibit key attributes of volitional movements, and that voluntary behaviours in vertebrates may generally be preceded by increased sensory sampling. Our results suggest that comparative studies of the neural basis of volition may therefore be possible in pulse-type Electric Fish, given the substantial homologies between the telencephali of teleost Fish and mammals.
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neural maps in the electrosensory system of weakly Electric Fish
Current Opinion in Neurobiology, 2014Co-Authors: Rüdiger Krahe, Leonard MalerAbstract:The active electrosense of weakly Electric Fish is evolutionarily and developmentally related to passive electrosensation and the lateral line system. It shows the most highly differentiated topographic maps of the receptor array of all these senses. It is organized into three maps in the hindbrain that are, in turn, composed of columns, each consisting of six pyramidal cell classes. The cells in each column have different spatiotemporal processing properties yielding a total of 18 topographic representations of the body surface. The differential filtering by the hindbrain maps is used by superimposed maps in the multi-layered midbrain electrosensory region to extract specific stimulus features related to communication and foraging. At levels beyond the midbrain, topographic mapping of the body surface appears to be lost.
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cellular and circuit properties supporting different sensory coding strategies in Electric Fish and other systems
Current Opinion in Neurobiology, 2012Co-Authors: Gary Marsat, Andre Longtin, Leonard MalerAbstract:Neural codes often seem tailored to the type of information they must carry. Here we contrast the encoding strategies for two different communication signals in Electric Fish and describe the underlying cellular and network properties that implement them. We compare an aggressive signal that needs to be quickly detected, to a courtship signal whose quality needs to be evaluated. The aggressive signal is encoded by synchronized bursts and a predictive feedback input is crucial in separating background noise from the communication signal. The courtship signal is accurately encoded through a heterogenous population response allowing the discrimination of signal differences. Most importantly we show that the same strategies are used in other systems arguing that they evolved similar solutions because they faced similar tasks.
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Signal cancellation in neural systems: encoding sensory input in the weakly Electric Fish
2012 11th International Conference on Information Science Signal Processing and their Applications (ISSPA), 2012Co-Authors: Gary Marsat, Leonard Maler, Jorge F. Mejias, Erik Harvey-girard, Andre LongtinAbstract:We present a biologically plausible mechanism to cancel simple redundant signals, i.e. sinusoidal waves, in neural circuits. Our mechanism involves the presence of: 1) stimulus-driven feedback to the neurons acting as detectors, 2) a large variety of temporal delays in the pathways transmitting such feedback, and 3) burst-induced long-term plasticity, all these factors being present in a wide set of neural systems. As an example, we consider the electrosensory lateral-line lobe of the weakly Electric Fish, which has been recently reported to employ this mechanism for the cancellation of redundant information in vivo. The cancellation is shown to be maintained for signals with different strengths of amplitude modulations.