Summary
Intracellular microelectrode recording methods have been used to study the electrical properties and discharge characteristics of spinal gamma motoneurons (axonal conduction velocity in the range 21–55 m/sec) of the anaesthetised cat. Small hyperpolarising current pulses of long duration applied through the recording electrode were used to measure the input resistances and the time constants of the neurons. Input resistances in the range 1.3–4.9 MΩ (mean, 2.65 MΩ) were found, with principal time constants of 4.6–11.4 msec (mean, 8.8 msec). Long-lasting depolarising current pulses evoked maintained discharges of action potentials at a high rate. These discharges began at a very high rate but then adapted over about 150 msec to reach a steady discharge. The relationship between steady discharge rate and injected current lay in the range 23–61 imp/sec/nA.
These properties are discussed in relation to the properties of alpha motoneurons, and also in relation to the functions of gamma motoneurons in activating intrafusal muscle fibres in muscle spindles.
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Westbury, D.R. (1981). Electrophysiological characteristics of spinal gamma motoneurons in the cat. In: Taylor, A., Prochazka, A. (eds) Muscle Receptors and Movement. Palgrave Macmillan, London. https://doi.org/10.1007/978-1-349-06022-1_10
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DOI: https://doi.org/10.1007/978-1-349-06022-1_10
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