INTEGRATION OF LOCOMOTOR BEHAVIOR PATTERNS OF THE HAGFISH

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Abstract
The California hagfish, Polistotrema stoutii, was subjected to operational procedures designed to illustrate the nature of the locomotor behavior patterns. Visual impressions of the deficiencies produced were used for interpreting the results. Simple cord section produces a disintegration of the total behavior pattern which can be re-established under strong external stimulation. That the behavior studied is a total pattern is indicated by the fact that isolation of a segment of the cord causes an immediate formation of a new site of initiation of the waves and also in that the wave length of the undulations integrated by isolated segments varies with the length of the segments. The undulatory waves represent moving sites of nervous integration and their speed and direction may be experimentally altered. Stimulation of the posterior end of the body and particularly of the tail results in the usual head-to-head undulations. Stimulation of the gill region initiates waves of reverse direction. Single hemisections of the cord do not incapacitate the animal for forward locomotion, though backward swimming seems impossible. Paired contralateral hemisections act as complete sections except that with strong stimulation, the pattern was more easily restored to normal. It is possible, with properly placed hemisections, to dissociate the undulatory pattern into right and left sided halves. Direct faradic stimulation of the sides of the cord also produced this fractionation.

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