Chapter 13 Dynamic response characteristics of the ampullae of Lorenzini to thermal and electrical stimuli

Wissing, Heimo; Braun, Hans; Schäfer, Klaus

doi:10.1016/s0079-6123(08)63004-6

Cited by 15 publications

(7 citation statements)

References 8 publications

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“…The elastic gel may simply maintain the geometry of the canals or serve to prevent infection, but Brown et al (2002) suggest that a gel-lled canal may also function as a low frequency antenna that is too sluggish to respond to frequencies above 1 kHz and sluggish enough to allow stimulation of the afferent nerve. As the glycoprotein-based gel possesses electrical characteristics similar to those of a semiconductor , the gel is likely able to translate subtle changes in temperature into an electrical stimulus (Sand, 1938;Wissing et al, 1988;Brown, 2003). However, these studies of temperature sensitivity were all performed on gel extracted from ampullary canals and studied in vitro.…”

Section: The Biochemical Nature Of the Ampullary Gelmentioning

confidence: 99%

The functional roles of passive electroreception in non-electric fishes

Collin¹,

Whitehead²

2004

Animal Biol

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Passive electroreception is a complex and specialised sense found in a large range of aquatic vertebrates primarily designed for the detection of weak bioelectric elds. Particular attention has traditionally focused on cartilaginous shes, but a range of teleost and non-teleost shes from a diversity of habitats have also been examined. As more species are investigated, it has become apparent that the role of electroreception in shes is not restricted to locating prey, but is utilised in other complex behaviours. This paper presents the various functional roles of passive electroreception in non-electric shes, by reviewing much of the recent research on the detection of prey in the context of differences in species' habitat (shallow water, deep-sea, freshwater and saltwater). A special case study on the distribution and neural groupings of ampullary organs in the omnihaline bull shark, Carcharhinus leucas, is also presented and reveals that prey-capture, rather than navigation, may be an important determinant of pore distribution. The discrimination between potential predators and conspeci cs and the role of bioelectric stimuli in social behaviour is discussed, as is the ability to migrate over short or long distances in order to locate environmentally favourable conditions. The various theories proposed regarding the importance and mediation of geomagnetic orientation by either an electroreceptive and/or a magnetite-based sensory system receives particular attention. The importance of electroreception to many species is emphasised by highlighting what still remains to be investigated, especially with respect to the physical, biochemical and neural properties of the ampullary organs and the signals that give rise to the large range of observed behaviours.

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Section: The Biochemical Nature Of the Ampullary Gelmentioning

confidence: 99%

The functional roles of passive electroreception in non-electric fishes

Collin¹,

Whitehead²

2004

Animal Biol

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“…An example is seen in the interval plot and in the return map of Fig. 2 at the temperature step from 15 • C to 10 • C. We assume that such irregularities occur when the operating range of both sets of nonlinearities approach each other, which might be expected especially during strong excitatory stimuli such as fast cooling of cold receptors (see [Braun et al, 1980;Wissing et al, 1988]). …”

Section: Continuous Transitions From Bursting To Subthreshold Oscillamentioning

confidence: 99%

Computer Simulations of Neuronal Signal Transduction: The Role of Nonlinear Dynamics and Noise

Braun

Huber

Dewald

et al. 1998

Int. J. Bifurcation Chaos

145

117

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Nonlinear ionic interactions at the nerve cell membrane can account for oscillating membrane potentials and the generation of periodic neuronal impulse activity. In combination with noise, external modulation of the endogenous oscillations allows for continuous transitions between a variety of impulse patterns. Such "noisy oscillators" afford, thereby, an important mechanism of neuronal encoding as is demonstrated here with experimental data from peripheral cold receptors and corresponding computer simulations.

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“…The top plot denotes the ambient temperature, while the bottom plot shows the corresponding average firing rate from an associated primary afferent nerve. The ambient temperature dependence has been discussed elsewhere; 11,12 we speculate here that a gel thermopower mechanism could help explain the sharp transient response.…”

Section: Figurementioning

confidence: 58%

“…9 The underlying firing rate per se is mildly sensitive to ambient temperature, but the ampullae also show dramatic, voltage-like, transient responses to abrupt temperature changes. 10,11,12 In fact, the transient responses leave the ampullae of Lorenzini unsurpassed in both their temperature and electrical sensitivity. The use of these organs in the sensory world of elasmobranchs is partially understood.…”

Section: The Electrosensorsmentioning

confidence: 99%

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Extracellular signal fluctuations in shark electrosensors

Brown

Hughes

Hutchison

2003

Fluctuations and Noise in Biological, Biophysical, and Biomedical Systems

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We examine the roll of an extracellular gel in the functioning of the electrosensors of elasmobranchs (sharks, skates, and rays). Here we focus on physical characteristics of the gel and their mechanistic relevance to the observed functioning of the electrosensors. The electrosensitive organs show sharp transient responses to both tiny electrical fluctuations and temperature fluctuations. We present a thermoelectric characterization of the gel. The data suggest a gel-mediated mechanism of transducing thermal fluctuations to electrical fluctuations in the electrosensor, independent of the sensing cells. We also present frequency-dependent electrical properties of the gel collected using electrical impedance spectroscopy. From these measurements we try to extract characteristic relaxation times. We analyze these results within the context of the electrosensors' bandwidth, as demonstrated in previous behavioral experiments.

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Chapter 13 Dynamic response characteristics of the ampullae of Lorenzini to thermal and electrical stimuli

Cited by 15 publications

References 8 publications

The functional roles of passive electroreception in non-electric fishes

The functional roles of passive electroreception in non-electric fishes

Computer Simulations of Neuronal Signal Transduction: The Role of Nonlinear Dynamics and Noise

Extracellular signal fluctuations in shark electrosensors

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