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Electric Organ (0):
Recent article
Electric Organ
Journal of Comparative Neurology (518)14 2010
Abstract
We show that the electric fish Apteronotus leptorhynchus can learn to recognize individual conspecifics based on a simple cue, the beat frequency of their summed sinusoidal electric organ discharges (EOD). Male fish produce transient communication signals (chirps) in response to mimic EODs. The chir...
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PMID: 20506470
PDF is available here.
PDF is available here.
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Hormones and Behavior (56)2 2009
Abstract
We investigated the role of androgens in potentiating circadian, pharmacological, and socially-induced plasticity in the amplitude and duration of electric organ discharges (EODs) of female gymnotiform fish. We first challenged female fish with injections of serotonin (5-HT) and adrenocorticotropic...
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PMID: 19450600
PDF is available here.
PDF is available here.
Biophysical Journal (97)1 2009
Abstract
We demonstrate the application of the technique to liposomes reconstituted with the peptide cation channel gramicidin, vesicles from native tissue containing the nicotinic acetylcholine receptor, and membranes from a recombinant cell line expressing the ionotropic P2X2 receptor. It is shown that sta...
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PMID: 19580777
PDF is available here.
PDF is available here.
Abstract
We review how the occurrence of multiple sodium channel paralogs has influenced the evolutionary history of three groups of fishes: pufferfish, gymnotiform and mormyriform electric fish. Pufferfish (tetraodontidae) produce a neurotoxin, tetrodotoxin, that binds to and blocks the pore of sodium chann...
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PMID: 21392277
PDF is available here.
PDF is available here.
Abstract
We have very few examples of chemical camouflage, and even these contain some ambiguity in deciding whether they are best seen as examples of background matching or mimicry. There are many examples of organisms that are adaptively silent at times or in locations when or where predation risk is highe...
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PMID: 19000976
PDF is available here.
PDF is available here.
Abstract
We transiently over-expressed S. macrurus MyoD (SmMyoD) and myogenin (SmMyoG) in mouse C3H/10T1/2 and NIH3T3 embryonic cells. RT-PCR and immunolabeling studies showed that SmMyoD and SmMyoG can efficiently convert these two cell lines into multinucleated myotubes which expressed differentiated muscl...
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PMID: 19598116
PDF is available here.
PDF is available here.
Journal of Neuroscience (28)37 2008
Abstract
We have been studying the regulation of Na(+) current inactivation in an electric fish model in which systematic variation in the rate of inactivation of the electric organ Na(+) current shapes the electric organ discharge (EOD), a sexually dimorphic, androgen-sensitive communication signal. Here, w...
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PMID: 18784298
PDF is available here.
PDF is available here.
Journal of Experimental Biology (211)Pt 13 2008
Abstract
We examined their expression in the electrocytes of the gymnotiform Sternopygus macrurus. We estimated the number of MRF genes in the S. macrurus genome and our Southern blot analyses revealed a single MyoD, myogenin, myf5 and MRF4 gene. Quantitative RT-PCR showed that muscle and EO transcribe all M...
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PMID: 18552307
PDF is available here.
PDF is available here.
Biological Cybernetics (98)6 2008
Abstract
The electric sense of mormyrids is often regarded as an adaptation to conditions unfavourable for vision and in these fish it has become the dominant sense for active orientation and communication tasks. With this sense, fish can detect and distinguish the electrical properties of the close environm...
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PMID: 18491164
PDF is available here.
PDF is available here.
Biological Cybernetics (98)6 2008
Abstract
We have created a biophysically realistic model of a wave-type weakly electric fish by using a genetic algorithm to calibrate the parameters to the electric field of a real fish. We use the model to study a pair of fish and compute the electric images of one fish onto the other at three representati...
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PMID: 18491161
PDF is available here.
PDF is available here.
Biological Cybernetics (98)6 2008
Abstract
We suggest that the differences in the types of sensory objects may drive the differences in the anatomical and physiological characteristics of these two cerebellum-like structures....
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PMID: 18491162
PDF is available here.
PDF is available here.
Journal of Experimental Biology (211)Pt 12 2008
Abstract
We contrasted the shortest playback pulse with simultaneous playback of one of four longer ones (424, 524, 628 and 716 micros). Pooled responses for all experimental subjects were stronger for the dipole playing back the longer pulse in a pulse pair. The difference in the number of head butts (Delta...
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PMID: 18515728
PDF is available here.
PDF is available here.
Abstract
We have developed a highly alpha7-selective alpha-conotoxin radioligand by iodination of a naturally occurring histidine. Both mono- and diiodo derivatives were generated and purified (specific activities were 2200 and 4400 Ci mmol(-1), respectively). The properties of the mono- and diiodo derivativ...
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PMID: 18323456
PDF is available here.
PDF is available here.
Journal of Experimental Biology (211)Pt 10 2008
Abstract
We found that in addition to chirps, the fish commonly produce a second signal type, a type of frequency rise called abrupt frequency rises, AFRs. By quantifying the behaviours associated with signal production, we find that Type 2 chirps tend to be produced when the fish are apart, following period...
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PMID: 18456893
PDF is available here.
PDF is available here.
Abstract
We characterize correlated activity in response to two biologically relevant classes of sensory stimuli in the primary electrosensory nuclei, the electrosensory lateral line lobe, of the weakly electric fish Apteronotus leptorhynchus. Our results show that these neurons can display significant corre...
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PMID: 18256161
PDF is available here.
PDF is available here.
Hormones and Behavior (53)3 2008
Abstract
We present evidence that two sets of serotonin receptors modulate the EOD in opposite directions. We found that the 5HT1AR agonist 8-OH-DPAT diminishes EOD duration and amplitude while the 5HT1AR antagonist WAY100635 increases these parameters. In contrast, the 5HT2R agonist alpha-Me-5-HT increases...
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PMID: 18206154
PDF is available here.
PDF is available here.
Journal of Experimental Biology (211)Pt 6 2008
Abstract
We must quantify their costs, including their energetic costs, the regulation of these costs, and the difference between the costs for the sexes. Here, we provide the first direct measurements of the relative energy expended on electric signals and show for the focal species Brachyhypopomus pinnicau...
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PMID: 18310126
PDF is available here.
PDF is available here.
Journal of Experimental Biology (211)Pt 6 2008
Abstract
We focus on Gnathonemus petersii (Günther 1862), an African fish of the family Mormyridae with a characteristic chin appendix, the Schnauzenorgan. Behavioural and anatomical results suggest that the mobile Schnauzenorgan and the nasal region serve special functions in electroreception, and can ther...
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PMID: 18310118
PDF is available here.
PDF is available here.
Journal of Neuroscience (28)7 2008
Abstract
We compared the ability of electroreceptors and ELL efferent neurons to encode the position of moving objects in the presence and absence of self-generated electrosensory signals caused by tail movements. Tail movements had strong effects on the responses of electroreceptors, substantially reducing...
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PMID: 18272681
PDF is available here.
PDF is available here.
Abstract
We demonstrate directly that each Torpedo nAChR carries at least four binding sites for the potent neuronal nAChR agonist, epibatidine, i.e., twice as many sites as for alpha-bungarotoxin. Using radiolabeled ligand binding techniques, we show that the binding of [(3)H]-(+/-)-epibatidine is heterogen...
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PMID: 18083118
PDF is available here.
PDF is available here.
Mathematical Biosciences (214)1-2 2008
Abstract
We consider the processing of narrowband signals that modulate carrier waveforms in sensory systems. The tuning of sensory neurons to the carrier frequency results in a high sensitivity to the amplitude modulations of the carrier. Recent work has revealed how specialized circuitry can extract the lo...
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PMID: 18514744
PDF is available here.
PDF is available here.
Biological Cybernetics (97)5-6 2007
Abstract
Computer simulations show that these phenomena can be explained by the presence of delayed feedback where the internal voltage is part of the feedback loop....
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PMID: 17926062
PDF is available here.
PDF is available here.
Abstract
Weakly electric fish react to resistance and capacitance of objects that locally amplify and distort their self-generated Electric Organ Discharge (EOD) received by their skin receptors. The successive-layer structure of tissues gives certain biological materials a kind of electrical anisotropy. A p...
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PMID: 17968555
PDF is available here.
PDF is available here.
Journal of Experimental Biology (210)Pt 23 2007
Abstract
We compared the electrocommunication signals of 13 species in the largest gymnotiform family, Apteronotidae. Playback stimuli were used to elicit chirps and rises. We analyzed EOD frequency and waveform and the production and structure of chirps and rises. Species diversity in these signals was char...
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PMID: 18025011
PDF is available here.
PDF is available here.
Journal of Experimental Biology (210)Pt 24 2007
Abstract
We investigated the influence of parallel fiber feedback onto pyramidal neurons of the electrosensory lateral line lobe (ELL) in weakly electric fish under open loop conditions. We mimicked naturalistic parallel fiber inputs in an ELL brain slice by implementing an experimentally based model of this...
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PMID: 18055632
PDF is available here.
PDF is available here.
Abstract
We demonstrate that the electrosensory space for prey detection has an unusual, omnidirectional shape. We compare this sensory volume with the animal's motor volume--the volume swept out by the body over selected time intervals and over the time it takes to come to a stop from typical hunting veloci...
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PMID: 18001151
PDF is available here.
PDF is available here.
Abstract
We propose that afferent bursting may mediate close-range tracking of planktonic prey....
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PMID: 17855580
PDF is available here.
PDF is available here.
Abstract
In spinal anesthesia, the effects of local anesthetics (LAs) are not completely explained by sodium channel inhibition. Other targets include neuronal nicotinic acetylcholine receptors (nAChRs). LA affinities for the Torpedo californica nAChR were measured by inhibition of [(3)H]TCP binding and corr...
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PMID: 17600837
PDF is available here.
PDF is available here.
Abstract
We tested the hypothesis that these behavioral responses result from non-jamming stimuli being misperceived as jamming stimuli. Responses to non-jamming stimuli were similar to JARs as measured by modulation rate tuning, sensitivity, and temporal dynamics. There was a smooth transition between the m...
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PMID: 17609965
PDF is available here.
PDF is available here.
Scientific American (297)2 2007
Abstract
Abstract
We identify a mechanism whereby the GABA(B) component of a feedback pathway to the electrosensory lobe is recruited to regulate the intrinsic burst dynamics and coding properties of pyramidal cells for these behaviorally relevant input signals. Through recordings in an in vitro slice preparation and...
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PMID: 17581845
PDF is available here.
PDF is available here.
Toxicology (236)3 2007
Abstract
Closing the gap between adverse health effects of aluminum and its mechanisms of action still represents a huge challenge. Cholinergic dysfunction has been implicated in neuronal injury induced by aluminum. Previously reported data also indicate that in vivo and in vitro exposure to aluminum inhibit...
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PMID: 17560001
PDF is available here.
PDF is available here.
Abstract
The wave-type African weakly electric fish Gymnarchus niloticus produces electric organ discharges (EODs) from an electric organ in the tail that is driven by a pacemaker complex in the medulla, which consists of a pacemaker nucleus, two lateral relay nuclei and a medial relay nucleus. The prepacema...
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PMID: 17406874
PDF is available here.
PDF is available here.
Neuroscience (145)2 2007
Abstract
We used an in vitro preparation to determine if the complex EOD of Gymnotus carapo was related to the membrane properties of electrocytes. We discovered that in addition to the three Na(+)-mediated conductances described in a recent paper [Sierra F, Comas V, Buño W, Macadar O (2005) Sodium-dependen...
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PMID: 17222982
PDF is available here.
PDF is available here.
Abstract
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 tha...
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PMID: 17335346
PDF is available here.
PDF is available here.
Physiology & Behavior (90)2-3 2007
Abstract
We investigate the effects of water temperature and day-night cycle upon EOD rate in this species during the breeding and non-breeding seasons. During the non-breeding season, EOD rate is a linear function of water temperature and exhibits counterclockwise hysteresis. During breeding, a thermal resi...
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PMID: 17178133
PDF is available here.
PDF is available here.
Abstract
We studied the physiology of deep and superficial granular cells in a slice preparation with whole cell patch recording and electrical stimulation of afferent fibers. Afferent stimulation evoked large all-or-none electrical excitatory postsynaptic potentials (EPSPs) and large all or none GABAergic i...
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PMID: 17229820
PDF is available here.
PDF is available here.
Abstract
We describe the effects of the GABA(A) receptor potentiating anesthetic etomidate on sensory processing, studied in a cerebellum-like structure, the electrosensory lateral line lobe (ELL) of mormyrid fish, in vitro. Previous studies have shown that the ELL integrates sensory input and removes predic...
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PMID: 17202233
PDF is available here.
PDF is available here.
Journal of Experimental Biology (210)Pt 5 2007
Abstract
Some fish emit electric fields generated by the coordinated activation of electric organs. Such discharges are used for exploring the environment and for communication. This article deals with the development of the electric organ and its discharge in Gymnotus, a pulse genus in which brief discharge...
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PMID: 17297140
PDF is available here.
PDF is available here.
Journal of Neuroscience (27)7 2007
Abstract
We provide evidence for corollary discharge-evoked inhibition that exerts potent control over the timing and probability of B spikes with little apparent effect on N spikes. The timing of this inhibition corresponds to the period during which repeated occurrence of B spikes causes depression of coro...
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PMID: 17301164
PDF is available here.
PDF is available here.
Proteomics (7)4 2007
Abstract
We took a combined cDNA sequencing and proteomic approach to define the molecular constituents of the T. californica electric organ. For soluble proteins, 2-DE was used and 224 protein spots were mapped. Plasma membrane fractions were analyzed using the shotgun approach (LC-MS/MS). A Torpedo cDNA li...
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PMID: 17309107
PDF is available here.
PDF is available here.
Abstract
Our results showed in the three electric organs that CS was the main sulfated GAG species detected, accompanied by small and diminutive amounts of CS/dermatan sulfate hybrid chains and heparan sulfate (HS), respectively. However, HS was not detected in the Sach's organ. CS was predominantly detected...
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PMID: 17161641
PDF is available here.
PDF is available here.
Physiology & Behavior (90)1 2007
Abstract
We show that the day-night oscillations in the EODs of the neotropical gymnotiform fish Brachyhypopomus pinnicaudatus free-run for over a week under constant photic and thermal conditions, and randomized food provisioning. Sex differences were apparent in strength and magnitude of the circadian osci...
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PMID: 16996093
PDF is available here.
PDF is available here.
Biosystems (87)2-3 2007
Abstract
We use a model of electrosensory perception with electrodynamics and explore a possible approach mechanism based on the sensory landscape distributed on electroreceptors. This paper presents that elasmobranchs can estimate the direction of the electric field by swaying their head, which will be a ba...
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PMID: 17045390
PDF is available here.
PDF is available here.
Abstract
Morphological and physiological changes produced by the intracellular localization of an alkyl long-chain tetraphenylporphyrin photosensitizer in Psammobatis extenta electrocytes were studied by means of SEM-EDS. Immediately after photosensitizer penetration, electrocytes swell and their convex face...
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PMID: 17145183
PDF is available here.
PDF is available here.
Abstract
We describe the cloning and molecular characterization of the cDNA for an NTPDase from Torpedo marmorata electric organ. The clone, obtained using the RACE-PCR technique, contains and open-reading frame of 1506bp and encodes a 502 amino acids protein that exhibits high homology with other NTPDases1...
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PMID: 17030469
PDF is available here.
PDF is available here.
Abstract
The electrosensory system is used for both spatial navigation tasks and communication. An electric organ generates a sinusoidal electric field and cutaneous electroreceptors respond to this field. Objects such as prey or rocks cause a local low-frequency modulation of the electric field; this cue is...
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PMID: 17925244
PDF is available here.
PDF is available here.
Biosystems (89)1-3 2007
Abstract
Afferent fibres of ampullary electroreceptor organs in electrosensitive fish fire spontaneously, that is, they fire without external stimulus. In the past it has been postulated that the spontaneous activity originates from a sustained level of neurotransmitter release delivered by the electrorecept...
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PMID: 17194525
PDF is available here.
PDF is available here.
FASEB Journal (20)14 2006
Abstract
We examined the expression patterns of several genes associated with multiple functions of skeletal muscle in mature electrocytes of S. macrurus. Our expression analyses detected transcripts for alpha-actin, alpha-acetylcholine (ACh) receptor (alpha-AChR), desmin, muscle creatine kinase (MCK), myosi...
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PMID: 17077280
PDF is available here.
PDF is available here.
Stimulus selectivity is enhanced by voltage-dependent conductances in combination-sensitive neurons.
Abstract
We know little about the underlying cellular mechanisms. The weakly electric fish Gymnarchus discriminates the sign of the frequency difference (Df) between a neighbor's electric organ discharge (EOD) and its own EOD by comparing temporal patterns of amplitude modulation (AM) and phase modulation (P...
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PMID: 17005607
PDF is available here.
PDF is available here.
Global electrosensory oscillations enhance directional responses of midbrain neurons in eigenmannia.
Abstract
We examined the differences in intracellularly recorded responses of midbrain neurons in awake, behaving fish to moving electrosensory images under electrosensory conditions that mimic solitary fish and fish in groups. In solitary conditions, moving objects elicited Gaussian or sinusoidal postsynapt...
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PMID: 16790600
PDF is available here.
PDF is available here.
Abstract
We show, the electrosensory system are signals that contain power in a narrow range of temporal (or spatial) frequencies. Characteristic of this class of signals is a slower variation in their amplitude, otherwise known as an envelope. There is evidence suggesting that, in the visual cortex, both na...
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PMID: 16983081
PDF is available here.
PDF is available here.
Journal of Neuroscience (26)36 2006
Abstract
We used a stimulus estimation technique to quantify the ability of P- and T-units to encode random modulations in amplitude and phase. As expected, P-units exhibited a clear preference for encoding amplitude modulations, whereas T-units exhibited a clear preference for encoding phase modulations. Su...
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PMID: 16957074
PDF is available here.
PDF is available here.
Journal of Neuroscience (26)32 2006
Abstract
We examined the effects of sensing behavior on a spike latency code in the active electrosensory system of mormyrid fish. These fish actively probe their environment by emitting brief electric organ discharge (EOD) pulses. Nearby objects alter the spatial pattern of current flowing through the skin....
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PMID: 16899717
PDF is available here.
PDF is available here.
Journal of Neurobiology (66)9 2006
Abstract
We used immunohistochemistry with six different antibodies raised against specific mammalian Kv1 alpha subunits (Kv1.1-Kv1.6) to characterize the distribution of Kv1-like channels in electromotor and electrosensory structures. Each Kv1 antibody labeled a distinct subset of neurons, fibers, and/or de...
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PMID: 16779822
PDF is available here.
PDF is available here.
Abstract
We explore the possible involvement of the TSd and of the GABA-ergic system in the modulation of the electric and skeletomotor displays. For this purpose, different doses of bicuculline (0.98, 0.49, 0.245, and 0.015 mM) and muscimol (15.35 mM) were microinjected (0.1 microL) in the TSd of the awake...
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PMID: 16862286
PDF is available here.
PDF is available here.
Abstract
We expected unidirectional coupling, whereby epithelial oscillations synaptically influence the spiking oscillators of afferent neurons. Using directionality analysis we confirmed unidirectional coupling of oscillators embedded in electroreceptors. We studied the performance of directionality algori...
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PMID: 16822043
PDF is available here.
PDF is available here.
Abstract
We show the following. (1) The internal low resistance of the fish's body shapes the image in two different ways: by funneling the current generated by the electric organ to the sensory surface, it increases the fields rostrally, thus enhancing the perturbation produced by nearby objects; and by inc...
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PMID: 16501980
PDF is available here.
PDF is available here.
Abstract
Weakly electric fish orient at night by employing active electrolocation. South American and African species emit 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 anima...
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PMID: 16645886
PDF is available here.
PDF is available here.
Abstract
We review here the distribution and function of a high-threshold potassium channel (Kv3.3) in the electrosensory lateral line lobe of the weakly electric fish Apteronotus leptorhynchus, with particular focus on the pyramidal cells in this brain structure. These cells contain both high-threshold Kv3....
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PMID: 16425062
PDF is available here.
PDF is available here.