Summary
Changes in the frequency of motoneurons innervating the right medial region of the longitudinal portion of the ventral superficial muscles were studied under chronic conditions. Extracellular potentials were correlated with intracellularly recorded EJP's; these varied in frequency from zero to 20 Hz. When animals carried different weights on their shells, the frequency increased with the load. The frequency was unrelated to the magnitude of the weights hung on the abdomen of a restrained animal or to its position. It is suggested that load compensation is produced by stimulation of phasic mechanoreceptors located in the abdominal surface and that no mechanism for maintaining a constant shell position above the substrate exists.
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I would like to thank Dr. Alan Wachtel, Dr. Richard Norman, Dr. Guillermo Pilar, and Mr. Jack Marelli for reading the manuscript, Ms. Wendy Wood for technical assistance, and Mr. Robert Ferris for participating in the initial phase of this work during the tenure of an NSF undergraduate summer fellowship. The research was supported by a grant GB-12368 to the author from the National Science Foundation.
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Chappie, W.D. Changes in abdominal motoneuron frequency correlated with changes of shell position in the hermit crabPagurus pollicarus . J. Comp. Physiol. 87, 49–64 (1973). https://doi.org/10.1007/BF00699295
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DOI: https://doi.org/10.1007/BF00699295