Asymmetry of Motor Behavior of the Goldfish in a Narrow Channel

Abstract

We studied swimming of goldfish fries about 3 cm long in a narrow channel by calculating the numbers of spontaneous turns on different sides. The ratio of fishes preferring to turn to the right vs to the left was 1.5: 1.0, respectively; two-thirds of the fishes demonstrated an ambilateral behavior. Experiments with compulsory 10-min-long rotation of the fishes (clockwise around the longitudinal body axis for fishes preferring right-side turns and anticlockwise for fishes preferring left-side turns) showed that the behavioral asymmetry smoothed somewhat after such a procedure, and a greater number of the fishes became ambilateral in their preference to turn to one side or another. After a one-or two-day-long test, the initial asymmetry of motor behavior completely recovered. Compulsory rotation of similar fishes in the opposite direction exerted no influence on the asymmetry in the choice of the turning direction. Adaptation-induced training of the fishes (using fatiguing long-lasting vestibular stimulation) resulted in some smoothing of motor asymmetry but did not change its general pattern. Thus, our findings allow us to believe that a noticeable proportion of the goldfish individuals (similarly to other animals and humans) is characterized by an innate asymmetry of the motor function with a clear preference for either right-or left-side turnings. These relations can be smoothed under experimental influences but are recovered later on, i.e., they are stable and are not fundamentally transformed. We assume that the asymmetry of motor behavior of fishes in a narrow channel can be an adequate pre-requisite for further examination of the asymmetry of the brain and motor centers controlling changes in locomotion (body turnings)

Morphofunctional effects of applications of glutamate and dopamine on the goldfish Mauthner neurons

“…Applications of the neurotransmitters were always performed at the right side of the fish's head, and the preferred side of turning is determined by the functioning of the contralateral MN [20]; this is why we used in the morphological part of the study mostly fishes preferably turning to the left, with domination of the right MN. The functional state of MNs in these experiments was estimated by separate calculation of rightward and leftward turnings in a straight channel and characterized by the motor asymmetry coefficient (MAC), i.e., by the ratio of the number of turnings toward the preferred side to the number of turnings toward both sides [21,22].…”

“…When studying the effects of applications of neurotransmitters, we combined these applications in a few cases with natural long-lasting stimulation of MNs (bilateral stimulation for estimation of the systemic function of both neurons and unilateral one for estimation of the function of an individual neuron) [21]. Sensory rotational stimulation was fulfilled by putting fishes into special drums rotated simultaneously in two planes (bilateral stimulation) or rotated in one plane around the longitudinal axis of the fish's body (unilateral stimulation) [22].…”

Stabilization of motor asymmetry in the goldfish under the influence of optokinetic stimulation

“…Before the beginning of the experiments, all fishes were divided into two groups, dextrals and sinistrals, according to their individually expressed preference of the side of turning manifested in the course of locomotion (i.e., motor asymmetry). The phenotypic motor asymmetry was estimated in a narrow straight chamber using the technique described earlier [7] and quantitatively characterized by calculation of the motor asymmetry coefficient (MAC), i.e., ratio of the number of full (90 deg or greater) turnings toward the preferred side and the total number of turnings toward both sides performed within a 5-min-long test period [11]. The level of integral functional activity of MNs of the fishes was estimated according to the total number of turnings realized within a 10-min-long interval [7].…”

“…Individual levels of receptivity of each dendrite and certain MN as a whole observed in each definite time moment also influence the selection of the turning direction. They are, to a considerable extent, determined, on the one hand, by the morphofunctional asymmetry of MNs that is manifested in behavior as the motor asymmetry of the fish [7,8] and, on the other hand, by variations of this asymmetry depending on the preceding loading on one afferent input or another. It was found that experimental adequate stimulation or unilateral elimination of one input selectively influences the structure and function of the individual MN; this leads to a change in the inborn motor asymmetry of the fish [9,10].…”

“…A direct mode of innervation of MNs fibers coming from the vestibular apparatus allows experimenters to influence these cells using simple adequate (natural) vestibular stimulations, e.g., rotation of the fish in a chamber (drum) around the longitudinal body axis. Estimation of the effects of such sensory stimulation on the fish's behavior and morphological parameters of MNs meets no serious difficulties [1,7,11]. To a great regret, changes related to vestibular stimulation and adaptation develop in this case exclusively in the lateral dendrite and soma of the MN.…”