Imidacloprid-induced facilitation of the proboscis extension reflex habituation in the honeybee.

Imidacloprid is a new insecticide from the family of the neonicotinoids, which interact with the insect nicotinic acetylcholine receptor. The effects of imidacloprid at a dose that does not affect sensory or motor functions are studied on non-associative learning abilities in the honeybee. The behavioral procedure is the habituation of the proboscis extension reflex (PER). Imidacloprid topically applied on the thorax (1 microl) at the doses of 5, 10, and 20 ng/bee induces an increase of the gustatory threshold defined as the lowest concentration of a sucrose solution applied to the antennae able to elicit the PER. The ability of the honeybee to move in an open-field-like apparatus is impaired at the doses of 2.5, 5, 10, and 20 ng/bee. These effects are amplified with time and reach a maximum 60 min after application. The lowest dose of 1.25 ng/bee has no effect on the gustatory function but increases the motor activity and facilitates the PER habituation independently of time. This result fits our hypothesis that a slight activation of the cholinergic system with a low dose of imidacloprid can facilitate a simple form of learning in the honeybee.

The ethological method as a means for evaluating stress in children two to three years of age during a dental examination.

A dental examination could be perceived by small children as an "at-risk" situation. The behaviors observed in these children during a dental examination depend not only on the examination situation but also on other factors, such as the sex of the child or the sex of the accompanying parent. The ethological method provided a means for evaluating behavioral differences due to the sex of the child and that of the accompanying parent. Results showed that girls appeared better able to master the examination situation than did boys, regardless of the sex of the accompanying parent. The girls appeared more secure, and exhibited more exploratory behavior than did the boys. The boys, on the other hand, appeared less secure than did the girls especially when the father was the accompanying parent.

Preliminary analysis of sensory disturbances and behavioral modifications of astronauts in space.

Behavioral modifications of astronauts over time spent in microgravity conditions was investigated according to an ethological approach based on video recordings during the Spacelab-1 mission. The method consisted of a description and a quantification of motor activity of a subject (movement and orientation) while performing working tasks. Each period of observation lasted 20 min, on days 1, 2, 3, 4, 7, 9, and 10. This provided a rather consistent frequency for behavioral sampling. The data were correlated with the findings of physiological experiments performed during the same spaceflight. Results revealed an increase in frequencies of certain motor outputs (e.g., yaw head and body movements, hand gripping, feet anchoring) which favored several specific sensory inputs (visual and tactile information). In addition to the appearance of head-down orientations while manipulating floating objects and during periods of body free-floating, the astronaut developed a new representation of the space and the objects around him in microgravity. These behavioral interpretations are discussed in the light of sensorimotor interactions and cognitive events.

[Not Available]. / Effets de la privation précoce de lumière sur l'orientation visuo-guidée chez un grillon Gryllus bimaculatus.

Visually guided orientation is studied during ontogeny in field crickets (Gryllus bimaculatus) bred into complete darkness from egg stage. It is compared to control animals bred in normal 12L 12D light cycle conditions. Control animals are strongly scototactic: whatever their age, 85% of them step towards low reflecting targets. On the contrary, for the experimental group (visually deprived), only 20% of the first larval instar crickets orientate towards vertical black stripes on a white background. A frame by frame analysis of video recordings allows to measure more accurate parameters of the orientation trails. Results show that experimental animals, already at the fifth larval instar, are able to orientate towards the targets as many as the control ones, nevertheless, they still present strong, permanent impairments of exploratory behaviour and visual fixation.

A method for identifying the nearby spatial cues used by animals during transverse orientation.

A method was proposed to locate the nearby cues used by an animal in the case of transverse orientation, where the animal keeps a constant angle with a spatial cue. By studying the value constancy of the angles formed by a moving animal and the direction of all spatial points (constancy being expressed through more or less strong variances), we set up a cartography of the neighbouring space of this animal during a path. Relatively to the area where a low variance is found for angular values, the animal maintains the best angular constancy. The orientating cue used during this path is probably included in this area. The method efficiency is first tested on path models, and then applied to filmed walking crickets. Its heuristic value is established whenever the observer do not want a priori assess the cues the animal is supposed to choose. The practical interest of the method lies in the knowledge it provides of the relative role played by the body axis translations and rotations in the visual fixation and retinal scanning of crickets.

[Electrophysiology of the retina and peripheral vision of Nemobius sylvestris]. / Données électrophysiologiques sur la rétine et le système visuel périphérique chez Nemobius sylvestrís.

1. Intracellular recordings were made from the retinula units of the cricket Nemobius sylvestris. The half width of the angular sensitivity function was estimated at 4,4 degrees. This mean acceptance angle is slightly smaller than the interommatidial angle. In these conditions of light adapted state and for ommatidia of the central eye region, an overlapping between adjacent ommatidia occurs, but only below the 50% sensitivity level. 2. Extracellular positive responses with the waveform of a smoothed retinula receptor potential were recorded and their origin from lamina is postulated. They were strongly influenced by lateral interactions with the neighbouring ommatidia, and it was concluded that a lateral inhibition in the first optic ganglion of the cricket does exist.

[A contribution to the study of ovarian cancer during pregnancy and the puerperium. 3 case histories (author's transl)]. / Contribution à l'étude du cancer de l'ovaire au cours de la gravido-puerpéralité. A propos de 3 cas.

The authors have seen three cancers out of 27 organic ovarian tumours which were diagnosed and operated on during pregnancy and the puerperium in 16790 deliveries. They recall the circumstances under which the condition was discovered and the difficulties in diagnosing it. They point out particularly the value of ultrasound and frozen section histological examination. They point out the therapeutic problems which are often of a dramatic nature because of the association of the two conditions and the prognosis which in turn depends mainly on the stage of the lesion and the operability of the tumour. Poor maternal prognosis in cases of ovarian cancer is an indication for operation before the 20th week of pregnancy of all tumours of the ovary which have been clinically diagnosed and confirmed by ultrasound.