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  • 1
    Electronic Resource
    Electronic Resource
    Sensory transduction in a locust multipolar joint receptor: The dynamic behaviour under a variety of stimulus conditions (1983)
    Springer
    Journal of comparative physiology 150 (1983), S. 207-215 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The dynamic behaviour of a multipolar mechanoreceptor in the locust femoro-tibial joint has been studied by linear systems analysis using both sinusoidal and pseudo-random mechanical stimuli. Experiments were performed at different mean positions of the joint and with a range of stimulating signal strengths. 2. The joint sensilla respond to increasing joint extension with increasing tonic firing of action potentials. Movements of the joint position produce modulation of the firing rate around the mean level which allows faithful reproduction of the input signal in the probability of action potential occurrence. However, at frequencies of about 1 Hz and above the response increasingly phase-locks to a repetitive signal. 3. For sinusoidal stimuli up to 1 Hz and for random stimuli up to 10 Hz the dynamic behaviour can be very well characterized as fractional differentiation. In the frequency domain this corresponds to a frequency response function which can be represented by the gain at a frequency of 1 radian/s and a fractional exponent of frequency. 4. The dynamic behaviour of these sensilla is discussed in terms of models of transduction for cuticular and multipolar sensilla.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00606370
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  • 2
    Electronic Resource
    Electronic Resource
    The effects of temperature on mechanotransduction in the cockroach tactile spine (1982)
    Springer
    Journal of comparative physiology 147 (1982), S. 251-258 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The dynamic behaviour of the cockroach femoral tactile spine can be characterised as fractional differentiation. In the frequency domain this corresponds to a frequency response function which can be completely represented by two parameters: the gain at a frequency of 1 radian/s and an exponent of frequency. 2. Frequency response functions for mechanotransduction in the tactile spine have been measured at temperatures in the range of 10–40 °C. Sensory transduction fails at temperatures a few degrees Celsius outside this range. 3. The effect of temperature upon sensory transduction is to multiply the entire response by a constant factor, independent of frequency, at each temperature. The multiplication factor increases with warming up to about 35 °C and then decreases rapidly. The data up to 35 °C is well fitted by an Arrhenius relationship with an activation energy of 18.6 kcal/ mole. 4. Changing the temperature has no effect upon the exponent of frequency which stays constant at approximately 0.5, corresponding to a system which performs semi-differentiation. 5. The possible sites of temperature sensitivity and sensory transduction in these mechanoreceptors are discussed. Possible origins of the semi-differentiation behaviour are reviewed and a visco-elastic travelling wave model of the tubular body is suggested. Comparisons are drawn throughout to the behaviour of Pacinian corpuscles, muscle spindle primary afférents and other cuticular mechanoreceptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609849
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  • 3
    Electronic Resource
    Electronic Resource
    Sensory transduction in an insect mechanoreceptor: extended bandwidth measurements and sensitivity to simulus strenght (1981)
    Springer
    Biological cybernetics 42 (1981), S. 87-94 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract The dynamic properties of sensory transduction in an insect mechanoreceptor, the femoral tactile spine of the cockroach, Periplaneta americana, have been studied by measurement of the frequency response function between randomly varying movement of the tactile spine and afferent action potentials from the sensory neuron which innervates it. The frequency response function of the mechanoreceptor has been characterized over a frequency range which is more than ten times larger than has previously been used for this preparation. Also the effects of varying the amplitude of the stimulating signal have been studied by the use of a range of input signal strengths from about 0.5 to 10 μm R.M.S. displacement. The measured frequency response functions can all be well fitted by a theoretical relationship which is a fractional exponent of complex frequency, provided that the time delay caused by conduction of the action potentials from the sensory dendrite to the recording electrodes is taken into account. Under small signal conditions the exponent of complex frequency is close to 0.5 but with larger displacements its value decreases to about half this value. The overall sensitivity of the receptor, as measured by the gain of the frequency response function at a natural frequency of 1 radian/s, is not significantly altered by changes in the input movement amplitude, so that the receptor behaves linearly in this respect. However, the mean rate of action potential occurrence is not linearly related to input movement amplitude. These results are discussed in terms of current theories of sensory transduction and the possible role of tubular bodies in the dynamic behaviour of insect cuticular mechanoreceptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336726
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  • 4
    Electronic Resource
    Electronic Resource
    Changes in the dynamic properties of locust photoreceptors at three levels of light adaptation (1985)
    Springer
    Biological cybernetics 52 (1985), S. 333-337 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract The frequency response function of phototransduction was studied in the locust compound eye at three levels of dim light adaptation. The eyes were stimulated with light from a green light emitting diode (LED) and the resulting changes in membrane potential were measured with intracellular electrodes. Absolute sensitivities and light adaptation levels were established by counting the arrivals of single photons in dark adapted eyes. Frequency response functions for phototransduction could be well fitted by a model developed earlier for fly compound eyes, which includes underdamped second order poles and a pure time delay. However, the locust data requires longer time constants for the poles and a longer delay than were used to fit the fly data, reflecting the slower response characteristics of the locust. Changing the level of light adaptation at dim levels caused changes in both the sensitivity and the dynamic properties of the photoreceptors. Sensitivity was reduced and significant decreases were seen in the delay and several time constants. The behavior also became much more damped, with one of the second order poles decomposing into first order poles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00355755
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  • 5
    Electronic Resource
    Electronic Resource
    Fine structure of the compound eyes and interfacetal mechanoreceptors of Cicindela tranquebarica Herbst (Coleoptera: Cicindelidae) (1980)
    Springer
    Cell & tissue research 206 (1980), S. 123-138 
    Details
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Sense organs ; Compound eyes ; Interfacetal mechanoreceptor ; Coleoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the compound eyes of adult Cicindela tranquebarica Herbst was examined by use of light, scanning, and transmission electron microscopy. Each ommatidium of these photopic eyes is eucone and has a “subcorneal layer” situated between the corneal lens and crystalline cone. A distal rhabdomere consisting only of microvilli from retinula cell seven, a more proximal, rectangular, fused rhabdom formed from six retinula cells, and a basal, eighth retinula cell with a spherical rhabdomere comprise the light sensitive portions of the ommatidium. The “subcorneal layer” consists of lamellae of endocuticular microfibrils and, in surface view, shows 11 concave polygons. Proximal extensions of the crystalline thread form inter-retinular fibres containing microtubules between retinula cells 1/2, 3/4, 5/6, and 7/1. The primary pigment cells are devoid of pigment granules, but are rich in rough endoplasmic reticulum. Proximal to each retinula cell nucleus are two basal bodies, one perpendicular to the other. The more proximal basal body extends two fibrillar feet proximally which fuse to form a horizontally-banded ciliary rootlet extending the length of the retinula peripheral to the rhabdom. Each ommatidium is surrounded by 16 secondary pigment cells. Interfacetal mechanoreceptors between some adjacent lenses each have a single bipolar neuron, with a dendritic sheath, tubular body, cilium, outer and inner sheath cells, and an axon surrounded by a neurilemma sheath cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233613
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  • 6
    Electronic Resource
    Electronic Resource
    Duplication of a peripheral sensory neuron in the cockroach Periplaneta americana (1984)
    Springer
    Cell & tissue research 236 (1984), S. 129-131 
    Details
    ISSN: 1432-0878
    Keywords: Neurobiology ; Sensillum ; Duplication ; Mechanoreceptors ; Periplaneta americana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We have recently examined the electrophysiology and ultrastructure of approximately 100 tactile spines from the metathoracic legs of adult cockroaches. In only one animal the single sensory neuron that innervates the spine was replaced with a pair of apparently identical neurons which we believe were both functional. As far as we are aware this is the first reported study of unprovoked duplication in a peripherally-located insect sensory neuron.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216522
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