Human handling and presentation of a novel object evoke independent dimensions of fear in Japanese quail.

Fear is a concept comprising several dimensions, but the nature of these dimensions and the relationships between them remain elusive. To investigate these dimensions in birds, we have used two genetic lines of quail divergently selected on tonic immobility duration, a behavioural index of fear. These two lines differ in their behavioural response to some, but not all, fear-inducing situations. In the present study, we investigated the contribution of human intervention in the differentiation between the two lines. To do this, fear responses towards a novel object were compared between lines in three conditions: (1) in the home cage without any human intervention, (2) in the home cage after human handling and (3) after placement in a novel environment by human handling. Fear behaviour differed between lines after human handling, with or without placement in a novel environment, but presentation of a novel object in the home cage without any human intervention induced similar fear responses in the two lines of quail. These results lead us to suggest that in quail, human intervention evokes a dimension of fear that differs from that evoked by sudden presentation of a novel object, in that these two dimensions may be selected independently.

Subdivisions of the arcopallium/posterior pallial amygdala complex are differentially involved in the control of fear behaviour in the Japanese quail.

Growing evidence suggests that the arcopallium/posterior pallial amygdala plays a major role in the control of fear behaviour in birds. This brain region comprises several subdivisions, but no direct evidence is available about its functional parcellation. The aim of the present study was to investigate the relative involvement of two subdivisions of the arcopallium/posterior pallial amygdala complex in four classical tests of fear in quail: the presentation of a novel object, the 'hole-in-the-wall', 'open-field' and tonic immobility tests. Bilateral electrolytic lesions damaging the posterior part of the arcopallium/posterior pallial amygdala resulted in an increase in fear behaviour in the 'open-field' test, whereas quail with lesions damaging the anterior part of the arcopallium displayed a decrease in an 'overall fear score', compared to quail with bilateral nidopallium or sham lesions. The differential involvement of the anterior and posterior parts of the arcopallium/posterior pallial amygdala in fear behaviour is discussed in view of the known connections between the arcopallium/posterior pallial amygdala complex and brain regions considered to be limbic in nature.

Behavioural and endocrine fear responses in Japanese quail upon presentation of a novel object in the home cage.

Most tests used to study fear in birds involve transferring them to a novel environment, which constitutes a bias in studies aiming at identifying the neural correlates of a specific fear-inducing situation. In order to investigate fear in birds with minimum interference by humans, behavioural and endocrine responses to the presentation of a novel object in the home cage were investigated in two lines of Japanese quail divergently selected for long or short duration of tonic immobility, a behavioural index of fear. Presentation of the novel object induced typical fear responses (avoidance of the object, increased pacing and increased plasma corticosterone levels) that were similar in the two lines of quail. Presentation of a novel object in the home cage thus appears to be a suitable stimulus to induce fear reactions in quail, with minimum interference from other motivational systems. The fact that quail of both lines reacted similarly in this test, while they are known to differ greatly in their behavioural responses to other fear-inducing tests, illustrates the multidimensional nature of fear.

Influence of the mother in the development of flavored-food preference in lambs.

The aim of the study was to determine the influence of the mother in the development of flavored-food preference in lambs. First, we demonstrated that lambs that ate flavored food in the presence of their mothers before weaning ate more of this food 1 month after weaning than lambs that ate flavored food with other ewes or lambs exposed to nonflavored food with their mothers. Second, lambs that could only see their mothers eating the flavored food and had access to the food's olfactory cues before weaning, showed similar preference for flavored food 1 month after weaning to lambs that ate the flavored food with their mothers. However, lambs that were separated from their mothers while their mothers consumed flavored food did not reveal a preference for it. Overall these results suggest that development of food preference in lambs depends mainly on observation of the mother, provided there is also access to olfactory cues characterizing the food.