ISSN:
1432-1106
Keywords:
Cerebellum
;
Cutaneous mechanoreceptors
;
Mossy fibers
;
Purkyně cells
;
Cat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary This paper gives an account of single Purkyně cell responses when three types of mechanical stimulation, as in the previous paper, are applied to the forefoot and hindfoot of the decerebrate unanesthetized cat. Attention was concentrated on the effects of brief mechanical pulses to the footpad. Recording was extracellular by glass microelectrodes and special precautions were taken in identifying the spike responses as being due to a single Purkyně cell and in securing its effective isolation for our computer averaging techniques, as described in the previous papers. All Purkyně cells were in the ipsilateral anterior lobe in the lateral vermis or pars intermedia of lobules III, IV, V, except for a few recordings in the extreme rostral zone of lobule VI. Mechanical pulses or taps evoked responses from many Purkyně cells which were pure excitatory, pure inhibitory or admixtures thereof. The latencies of onset were usually in the range of 12–20 msec from the onset of the tap, which tends to be a little longer than the observed latencies for mossy fiber responses described in the preceding paper. There was often a considerable difference in the sizes of the responses evoked from different pads of the same foot, and the usual threshold for response was below 0.2 mm amplitude. Durations of responses were usually 10–20 msec for excitation and 50–100 msec for inhibition. Pressure pulses to the central foot pads of 2 sec duration evoked a wide variety of responses: brief phasic at “on” and “off” that could be admixtures of excitation and inhibition; almost pure tonic excitations or inhibitions that were well maintained during the 2 sec; phasic-tonic responses in various relative degrees. Usually 500 g was maximally effective and the threshold was below 100 g. Hair receptors were stimulated preferentially by brief air jets, there being brief excitatory or inhibitory responses much as with taps, but with rather longer latency. The effective area was usually fairly extensive over the hairy skin of the foot. In general the effects on Purkyně cells by cutaneous mechanoreceptors acting via mossy fibers were in accord with the mossy fiber responses reported in the preceding paper and with the well-known excitatory and inhibitory effects that are exerted by mossy fiber inputs on Purkyně cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00235911
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