Biomedical subjects

A Bisazza

Publications and source records attributed to A Bisazza.

23 records · Page 2Linked to original sources

PubMed1997

Pawedness and motor asymmetries in toads.

Pawedness was investigated in three species of toads, Bufo bufo , Bufo viridis , and Bufo marinus. Samples from natural populations were collected in two successive years and tested during attempts to remove a strip of paper stuck onto the snout ( Bufo bufo and Bufo viridis ) or during attempts to remove an elastic balloon wrapped around the head ( Bufo bufo ). A preferential right forelimb use at the population level was observed in Bufo bufo in both tests, whereas no clear pawedness was observed in Bufo viridis. Bufo marinus also showed no laterality in the paper-strip test, but it appeared to be strongly lateralised in another test that investigated which side the toad rotated when turned on its back underwater. Preferentially turning to the toad's left side as part of a righting response, Bufo marinus released the left forelimb first, using the right forelimb to control the roll to the upright position, and push to the surface. These results suggest that preferential limb use has a long evolutionary history, which dates back to early tetrapods.

Journal Article↗

PubMed1996

Lateralization of displays during aggressive and courtship behaviour in the Siamese fighting fish (Betta splendens).

Evidence for right-left asymmetries in eye use at the individual level in the Siamese fighting fish, Betta splendens, is reported. When faced with their mirror image (in two daily trials of 10 min each), adult male Betta splendens showed consistency in their right or left eye use during threat lateral displays. Moreover, if one side was preferred by an individual to exhibit the lateral displays, then the duration of the displays on that side was longer than the duration of the displays on the other side. Similar findings were obtained when a sample of animals was tested for eye use during courtship displays in the presence of a female. Furthermore, consistency in eye use was observed in fish tested first with the mirror and then, 2 months later, with the female. Results are discussed with respect to the issue of the evolution of brain lateralization.

Aggression↗

PubMed1996

Rotational bias in mosquitofish (Gambusia holbrooki): the role of laterality and sun-compass navigation.

Spontaneous rotational preferences in swimming of mosquitofish (Gambusia holbrooki) were investigated. Females, but not males, swam in circular tanks preferentially anticlockwise in the afternoon but not in the morning. Females' rotational preferences appeared to be related to a sun-compass orientation mechanism, as they disappeared under diffuse lighting conditions and when using naive females (i.e. using individuals never exposed to sunlight). Under repeated testing, however, the bias produced by the sun-compass mechanism tended to disappear, but females still showed rotational preferences that became stable and consistent at the individual level. Males too showed consistent individual rotational preferences under repeated testing. It is concluded that rotational bias in mosquitofish is due to two independent phenomena: a sun-compass navigation mechanism, which is related to the intensity of predation, and a behavioural lateralisation at the individual level, which is likely to reflect neural asymmetries in motor or sensory systems.

Journal Article↗

PubMed1995

Lateralization of predator-evasion response in a teleost fish (Girardinus falcatus).

Evidence of lateral asymmetries in the direction of turning during escape behaviour in a species of poeciliid fish, Girardinus falcatus, is reported. When repeatedly faced with a simulated predator (in five successive sessions, spaced 7 days apart), immature Girardinus falcatus exhibited a significant population bias to turn right on the first session and a progressive bias to turn left in subsequent sessions. Mature Girardinus were then tested to check whether the shift in the direction of turn with repeated sessions depended on maturation or habituation. It was found that adult Girardinus showed a slight population bias to turn right in the first session and a strong subsequent bias to turn left after repeated sessions. The implications of these findings to our current understanding of the evolution of brain lateralization are discussed.

Animals↗

PubMedDate not supplied

Lateralization of response to social stimuli in fishes: a comparison between different methods and species.

We measured the time spent in monocular viewing during inspection of their own mirror images in females of three species of fish (Xenotoca eiseni, Gambusia holbrooki and Xenopoecilus sarasinorum) using a rectangular tank in which animals could observe their own reflections in two mirrors positioned along the major walls, and in females of five species of fish (X. eiseni, G. holbrooki, X. sarasinorum, Danio rerio and Gnatonemus petersii) using a quasi-circular tank in which fish could rotate clockwise or anticlockwise and observe their own reflections in a mirror positioned along the outer wall. Results revealed a consistent left-eye preference during initial sustained fixation in all species irrespective of the apparatus. However, in the quasi-circular tank, fish showed more variability of response. The asymmetry was apparent during the first 5 min of observation and tended to fade thereafter, probably as a result of habituation. These findings add to current evidence for a quite invariant pattern in the direction of lateralization in similar tasks in a variety of vertebrate species, with a preferential involvement of structures located to the right side of the brain in response to the viewing of images of conspecifics.

Animals↗