Attentional Processing in C57BL/6J Mice Exposed to Developmental Vitamin D Deficiency

Epidemiological evidence suggests that Developmental Vitamin D (DVD) deficiency is associated with an increased risk of schizophrenia. DVD deficiency in mice is associated with altered behaviour, however there has been no detailed investigation of cognitive behaviours in DVD-deficient mice. The aim of this study was to determine the effect of DVD deficiency on a range of cognitive tasks assessing attentional processing in C57BL/6J mice. DVD deficiency was established by feeding female C57BL/6J mice a vitamin D-deficient diet from four weeks of age. After six weeks on the diet, vitamin D-deficient and control females were mated with vitamin D-normal males and upon birth of the pups, all dams were returned to a diet containing vitamin D. The adult offspring were tested on a range of cognitive behavioural tests, including the five-choice serial reaction task (5C-SRT) and five-choice continuous performance test (5C-CPT), as well as latent inhibition using a fear conditioning paradigm. DVD deficiency was not associated with altered attentional performance on the 5C-SRT. In the 5C-CPT DVD-deficient male mice exhibited an impairment in inhibiting repetitive responses by making more perseverative responses, with no changes in premature or false alarm responding. DVD deficiency did not affect the acquisition or retention of cued fear conditioning, nor did it affect the expression of latent inhibition using a fear conditioning paradigm. DVD-deficient mice exhibited no major impairments in any of the cognitive domains tested. However, impairments in perseverative responding in DVD-deficient mice may indicate that these animals have specific alterations in systems governing compulsive or reward-seeking behaviour

Relative importance of odour and taste in the one-trial passive avoidance learning bead task

The relative importance of taste and odour cues in a one-trial passive avoidance learning (PAL) task was examined. One-day-old chicks were presented with a small bead and different combinations of the taste and odour of methyl anthranilate (MeA). The chicks had received three consecutive pretraining trials where they were presented with white, red, and blue beads. They were then trained with a red bead presented in one of four possible conditions: dry and unscented, with the odour but not the taste of MeA, with the bitter taste but not the odour of MeA (the chicks' nostrils were occluded with a wax preparation), or with the taste and odour of MeA. Recall was tested 10 min after training by presenting a red and then a blue bead with no odour or taste added. The number of pecks made at the bead and the number of bouts of head shaking during each of the trials were scored. During testing, chicks that were trained with the odour of MeA alone pecked less at a red bead than at a blue bead, compared with chicks trained with a dry and unscented bead, indicating that they discriminated between the training bead and a bead of a different colour. There was no significant difference between the discrimination ratio of chicks trained with the odour, taste, or taste and odour of MeA. These results demonstrate that chicks can perform PAL using taste and/or odour cues. (C) 1997 Elsevier Science Inc

Effects of training procedure on memory formation using a weak passive avoidance learning paradigm

One-day-old chicks will learn, in one trial, to avoid pecking a bead that tastes aversive. This procedure is used widely as a model for learning and memory, although a variety of training procedures and bead types are used in different laboratories. Here we report that the decay of memory following training on a weak (10% methylanthranilate) avoidance task is dependent on the training procedure rather than the characteristics of the beads or the strain of chick used. Chicks that have been presented with a bead in pretraining and a similar bead coated in MeA during training fail to avoid the bead when tested 2 h posttraining, whereas chicks presented with a bead of particular color and size for the first time at training demonstrate high levels of avoidance at 2 h posttraining. These results resolve the differences in the time course of memory formation for a weak passive avoidance task described by the groups at Monash University (Crowe, Ng, & Gibbs, 1989) and the Open University (Sandi & Rose, 1994). (C) 1997 Academic Press

Responses to odorants by the domestic chick

We have developed a method to measure responses to graded concentrations of volatile chemicals by domestic chicks (Gallus gallus domesticus). Concentration-response curves were obtained, from which 50% effective concentration (EC(50)) values were determined. One-day-old chicks were presented with a 4-mm diameter colored bead, at which they pecked readily, affixed to a tube containing log dilutions of odorant. The chick was exposed to the odorant when it pecked at the bead. Various methods of presentation were tried. The method preferred minimized the number of chicks required by allowing repeated testing. Habituation to visual cues was prevented by changing the color of the bead on each presentation. The number of pecks directed at the bead and the amount of head shaking that occurred while the chick was exposed to the stimulus during the 10-s trial were scored from video recordings. Chicks demonstrated increased amounts of head shaking with increasing concentrations of isoamyl acetate or allyl sulfide; low concentrations stimulated pecking and higher concentrations suppressed it. Coincident EC(50) values for pecking and head shaking (approximately 1% for isoamyl acetate and allyl sulfide) indicate that they may be controlled by the same mechanism, albeit inversely. There was no relationship between the amount of pecking and the concentration of eugenol, but the EC(50) value for head shaking was at the 30% concentration. The results demonstrate that one-day-old chicks show graded responses to graded concentrations of odors and that they demonstrate differential sensitivity to different odorants. Possible involvement of the trigeminal system in these responses is considered. Copyright (C) 1996 Elsevier Science Inc

Changes in olfactory responsiveness by the domestic chick after early exposure to odorants

There is increasing evidence that odorants are important in the formation of attachments by the domestic chick, Gallus gallus domesticus. We investigated whether early exposure to nonaversive odorants altered the responses of 1-day-old chicks to a number of odorants from naturalistic sources, including feathers and faeces of adult chickens, wood litter and food (chick starter mash). The odorants were delivered by dynamic olfactometry, in which air containing different concentrations of each odorant was presented separately to individually housed chicks together with a small, coloured bead at which they could peck. When tested with a faecal odorant, but not the other odorants, control chicks, incubated and reared under standard conditions, shook their heads more but their pecking responses did not vary for any of the odorants tested. Chicks that had been exposed to a moist-food odorant from embryonic day 20 to 18 h posthatching and tested with odorants from either moist or dry food pecked less than controls but shook their heads the same amount. Early exposure to the moist-food odorant did not affect responses to the odorants of feathers or faeces. Chicks apparently learn about their olfactory environment during the later part of incubation and in the early posthatching period and the memory formed alters behaviour on day 1 posthatching. (C) 1999 The Association for the Study of Animal Behaviour

Chemosensory input and lateralization of brain function in the domestic chick

One-day old domestic chicks ('Gallus gallus domesticus') show concentration-dependent behavioural responses to olfactory cues. In the present study we investigated the lateralized olfactory responses of 1-day-old chicks to the odours of eugenol and iso-amyl acetate. In experiment 1 different concentrations of each odour were presented in repeated trials to chicks housed individually. The odours were presented together with a small coloured bead at which the chick pecked. When tested with the highest concentration of eugenol (100% v/v), the chicks demonstrated more head shaking when their left nostril was occluded (RN; right nostril in use) than when their right nostril was occluded (LN; left nostril in use). No such lateralization occurred in response to iso-amyl acetate. This result was confirmed in a second experiment in which the chicks were tested with unscented stimuli, 100% eugenol and 100% isoamyl acetate. In experiment 3 we found that occluding both the chicks' nostrils abolished the head shaking response to eugenol and to iso-amyl acetate. Thus, the chicks' head shaking responses to the odorants eugenol and iso-amyl acetate are mediated primarily by inputs from within the nasal cavity, and not by oral or occular inputs. The present results are consistent with the hypothesis that there is lateralization to olfactory cues and that it is dependent on the involvement of receptors inside the nasal cavity. We suggest that differences in lateralized olfactory responses to different odours are affected by the relative involvement of intranasal olfactory and trigeminal chemoreceptors

Chemosensory input and lateralization of brain function in the domestic chick

One-day old domestic chicks (Gallus gallus domesticus) show concentration-dependent behavioural responses to olfactory cues. In the present study we investigated the lateralized olfactory responses of 1-day-old chicks to the odours of eugenol and iso-amyl acetate. In experiment I different concentrations of each odour were presented in repeated trials to chicks housed individually. The odours were presented together with a small coloured bead at which the chick pecked. When tested with the highest concentration of eugenol (100% v/v), the chicks demonstrated more head shaking when their left nostril was occluded (RN; right nostril in use) than when their right nostril was occluded (LN; left nostril in use). No such lateralization occurred in response to iso-amyl acetate. This result was confirmed in a second experiment in which the chicks were tested with unscented stimuli, 100% eugenol and 100% iso amyl acetate. In experiment 3 we found that occluding both the chicks' nostrils abolished the head shaking response to eugenol and to iso amyl acetate. Thus, the chicks' head shaking responses to the odorants eugenol and iso-amyl acetate are mediated primarily by inputs from within the nasal cavity, and not by oral or occular inputs. The present results are consistent with the hypothesis that there is lateralization to olfactory cues and that it is dependent on the involvement of receptors inside the nasal cavity. We suggest that differences in lateralized olfactory responses to different odours are affected by the relative involvement of intranasal olfactory and trigeminal chemoreceptors. (C) 2002 Elsevier Science B.V. All rights reserved

c-fos mRNA expression associated with PGF(2 alpha)-induced nest-building behaviour in female pigs

Domestic pigs, Sus scrofa, build a maternal nest on the day before parturition. A model for nest building has been established in pigs, in which exogenously administered prostaglandin (PG) F-2alpha. may be used to elicit nesting behaviour in cyclic, pseudopregnant and pregnant pigs. The central mechanisms mediating this response are unknown. The present study determined regional brain activity using semi-quantitative analysis of c-fos mRNA, after induction of nest-building behaviour by PGF(2alpha) in Large White pseudopregnant pigs. Oestradiol valerate injections (5 mg/day) were given on days 11-15 of the oestrous cycle to induce pseudopregnancy. The pigs were housed individually in pens (2.8 x 1.7 m) containing straw. On the test day (day 46 or 47 of pseudopregnancy) animals were injected with 3 ml saline (n=5) or 15 mg of PGF(2alpha) (Lutalyse, Upjohn; n=6) intramuscularly. Pigs treated with PGF(2alpha), but not saline, displayed bouts of rooting, pawing and gathering straw, which we interpret as nest building behaviour. The pigs were killed 65 min after treatment, which was 30 min after peak nest building activity, and the brain, uterus and ovaries removed for processing using in situ hybridisation. Saline-treated pigs had elevated levels of c-fos mRNA, compared to background, in the pituitary, corpus luteum and uterus, and a lower, but elevated, level of expression in cerebellum, cortex, hippocampus and olfactory bulb. PGF(2alpha)-treated pigs had significantly higher levels of c-fos mRNA expression than saline-treated pigs in the parvocellular and magnocellular regions of the hypothalamic paraventricular nucleus, the supraoptic nucleus (including the pars dorso-medial is), the neural lobe of the pituitary gland and the cerebellum. PGF(2alpha)-treated pigs also had significantly higher c-fos induction in corpus luteum. These data show that the pattern of c-fos mRNA expression in specific brain areas is different between pigs that show PGF(2alpha)-induced nest building and saline-injected controls. (C) 2002 Elsevier Science B.V. All rights reserved