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  • 1
    Electronic Resource
    Electronic Resource
    An electronic model of neuroelectric point processes (1968)
    Springer
    Biological cybernetics 5 (1968), S. 30-46 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Zusammenfassung Eine umfassende Darstellung der Nervenzellmembran wird durch eine Kombination von Hodgkin-Huxley-Beschreibung der elektrisch erregbaren Leitwerte und Eccles-Beschreibung der synaptisch induzierten Leitwerte wiedergegeben. Diese Darstellung wird in einem elektronischen Modell veranschaulicht. Nichtlineare aktive Schaltungen werden benützt, um Leistungen zu entwickeln, die in ihrer Form mit den zeit- und spannungsabhängigen Leitwerten der Beschreibungen übereinstimmen. Die Leistungen werden mit Hilfe von Multiplikatoren in äquivalente Leitwerte umgewandelt. Das elektrische Modell enthält 24 kontrollierbare Parameter, von denen jeder mit einem in der Beschreibung übereinstimmt. Zur Einstellung der Parameter sollte man eine Strategie benützen, die soweit wie möglich die Werte von Hodgkin und Huxley (s. Tafel) als Parameter verwendet. Kleine Abweichungen von diesen Werten werden als mindere Störungen der grundliegenden Zusammenstellung betrachtet. Als Beispiel einer systematischen Untersuchung des Einflusses einer Veränderung verschiedener Parameter wurden die Spannungsschwingungen gewählt. Die Frequenz der ungedämpften Schwingungen beträgt ungefähr 50 Hertz. Verschiedene andere kleine Änderungen der Parameter können Schwingungsfrequenzen von 4 Hertz hervorrufen. Mit großen Störungen der Grundwerte kann man auch Schwingungsfrequenzen im Werte l Hertz erlangen. Es wird vorgeschlagen, daß die kombinierten Eccles- und Hodgkin-Huxley-Beschreibungen die Mehrzahl der neuroelektrischen Vorgänge einzelner Nervenzellen darstellen könnten. Dieser Vorschlag wird durch weitere Ergebnisse bestätigt. Die Beobachtung wird jedoch ausgedrückt, daß die zusammenfassende Darstellung in wenigstens einem Falle, den Nervenzellen des Hummer-Herznervenknotens, nicht zulänglich ist.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00288896
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Seismic communication between the burrows of kangaroo rats, Dipodomys spectabilis (1997)
    Springer
    Journal of comparative physiology 181 (1997), S. 525-531 
    Details
    ISSN: 1432-1351
    Keywords: Key words Kangaroo rat ; Footdrum ; Seismic ; Communication ; D. spectabilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Banner-tailed kangaroo rats, Dipodomys spectabilis, footdrum to produce substrate-borne and airborne acoustic energy. Previous studies show that they communicate territorial ownership via airborne footdrumming signals. The research reported here used simulated footdrum patterns generated by an artificial `thumper' to address the question of whether kangaroo rats communicate through seismic components of these acoustic signals. With microphones suspended in sealed burrows, we found that airborne sounds were attenuated by approximately 40 dB as they passed through the burrow wall into the burrow chamber. The substrate-borne vibrations from the thumper yielded sound approximately 40 dB greater in peak amplitude than the attenuated airborne sound. Thus, 99.9% of the peak power of the thumper was transmitted directly through the substrate into the burrow. The rats in sealed burrows timed their responses to playbacks of footdrums from the thumper and a loudspeaker so they did not initiate a drumming sequence during either the seismic or airborne signals. When these signals were masked by loud noise, the rats continued to drum to the seismic signal but drummed randomly during the airborne playback. These results suggest that the sealed burrow provides a quiet place in which D. spectabilis can listen for substrate-borne communications from conspecifics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590050136
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Scanning electron microscope observations of saccular ultrastructure in the mudpuppy (Necturus maculosus) (1972)
    Springer
    Cell & tissue research 123 (1972), S. 441-457 
    Details
    ISSN: 1432-0878
    Keywords: Sacculus ; Otolith ; Receptors ; Hair cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning electron microscopy revealed two types of hair cells in the sacculus of an amphibian, the mudpuppy (Necturus maculosus). Both types were surrounded by microvilli-covered sustentacular cells. The peripheral hair cells have shorter, thinner stereocilia and longer kinocilia than the hair cells in the central macula. The hair cells generally were found to be oriented with their stereocilia gradient directed toward the periphery of the macula. A nearly semicircular stria separated those directed forward and outward from those directed rearward and outward. Two basic types of otoconia were found in the otolith, and X-ray analysis revealed the entire otolith to be composed of aragonite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335541
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Evidence concerning the morphogenesis of saccular receptors in the bullfrog (Rana catesbeiana)Research sponsored by the Joint Services Electronics Program, Contract F44620-71-C-0087 and the United States Public Health Service, National Institute of Health, grant GM-17523-02. (1973)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973), S. 351-361 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A dichotomy of hair-cell types has been found in the bullfrog sacculus, and considerable evidence supports the view that one type (“peripheral”) is transformed during macular growth to the other type (“central”). Between the periphery and the center of the macula, one finds a gradation of form from “peripheral” to “central” type. Occasionally in adults and more often in stage-26 tadpoles one finds the presumably younger peripheral type of hair cell occurring well beyond the limits of the macula proper. The apparent morphogenic sequence for saccular hair cells is (1) development of a kinocillum on an endolymphatic epithelial cell, (2) gradual transformation of microvilli into stereocilia, (3) growth of the stereocilia and development of kinociliary bulb, (4) achievement of final size and form.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051390305
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    Paper (German National Licenses)
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