Surface species of the nematic mixture E7 obtained by electrochemical insertion of Li+ ions.

We studied here the influence of Li+ ions on the benzene rings of nematic mixture E7, which is electrochemically adsorbed onto gold electrode surface, to highlight the ability of this mixture for the applications in the field of the rechargeable Li+-ion batteries. Raman spectra support the changes observed in electrochemical analyses while contact angle measurements show that wetting properties of E7 layer were modified after deposition of this mixture onto gold support and the doping with Li+ ions. Contact angle of acetonitrile drops and Raman spectrum of the film of E7 nematic mixture are two main properties which show deep modifications into the film by electro chemical deposition.

Prenatal maternal stress is associated with behavioural and epigenetic changes in Japanese quail.

Prenatal maternal stress (PMS) influences many facets of offspring's phenotype including morphology, behaviour and cognitive abilities. Recent research suggested that PMS also induced epigenetic modifications. In the present study, we analysed, in the Japanese quail, the effects of PMS on the emotional reactivity and cognitive abilities of the F1 offspring. We also investigated in the hippocampus, the paraventricular hypothalamic nucleus and subnuclei of the arcopallium/amygdala the level of two histone post-translational modifications, H3K4me2 and H3K27me3, known to be impacted by stress. We found that PMS does not affect F1 quail's learning abilities but increases their emotional reactivity. Moreover, we demonstrated that PMS induced an increased density of H3K27me3 positive cells, in the hippocampus, paraventricular hypothalamic nucleus and dorsal nucleus of the amygdala, but not variations of H3K4me2. As these brain regions are involved in the control of vertebrates' emotional responses, the effect of PMS on the epigenetic mark H3K27me3 could possibly be a mechanism involved in the behavioural effects we observed in F1 quail.

Microbiota and stress: a loop that impacts memory.

Chronic stress and the gut microbiota appear to comprise a feed-forward loop, which contributes to the development of depressive disorders. Evidence suggests that memory can also be impaired by either chronic stress or microbiota imbalance. However, it remains to be established whether these could be a part of an integrated loop model and be responsible for memory impairments. To shed light on this, we used a two-pronged approach in Japanese quail: first stress-induced alterations in gut microbiota were characterized, then we tested whether this altered microbiota could affect brain and memory function when transferred to a germ-free host. The cecal microbiota of chronically stressed quails was found to be significantly different from that of unstressed individuals with lower α and ß diversities and increased Bacteroidetes abundance largely represented by the Alistipes genus, a well-known stress target in rodents and humans. The transfer of this altered microbiota into germ-free quails decreased their spatial and cue-based memory abilities as previously demonstrated in the stressed donors. The recipients also displayed increased anxiety-like behavior, reduced basal plasma corticosterone levels and differential gene expression in the brain. Furthermore, cecal microbiota transfer from a chronically stressed individual was sufficient to mimic the adverse impact of chronic stress on memory in recipient hosts and this action may be related to the Alistipes genus. Our results provide evidence of a feed-forward loop system linking the microbiota-gut-brain axis to stress and memory function and suggest that maintaining a healthy microbiota could help alleviate memory impairments linked to chronic stress.

Tetragonal-Cubic Phase Transition and Low-Field Dielectric Properties of CH3NH3PbI3 Crystals.

The frequency and temperature dependence of dielectric properties of CH3NH3PbI3 (MAPI) crystals have been studied and analyzed in connection with temperature-dependent structural studies. The obtained results bring arguments for the existence of ferroelectricity and aim to complete the current knowledge on the thermally activated conduction mechanisms, in dark equilibrium and in the presence of a small external a.c. electric field. The study correlates the frequency-dispersive dielectric spectra with the conduction mechanisms and their relaxation processes, as well as with the different transport regimes indicated by the Nyquist plots. The different energy barriers revealed by the impedance spectroscopy highlight the dominant transport mechanisms in different frequency and temperature ranges, being associated with the bulk of the grains, their boundaries, and/or the electrodes' interfaces.

Training level reveals a dynamic dialogue between stress and memory systems in birds.

Chronic stress profoundly affects forms of declarative memory, such as spatial memory, while it may spare non-declarative memory, such as cue-based memory. It is known, however, that the effects of chronic stress on memory systems may vary according to the level of training of an individual was submitted. Here, we investigated, in birds, how chronic stress impact spatial and cue-based memories according to training level. For that, control and chronically stressed Japanese quail were trained in a task that could be solved using spatial and cue-based memory and tested for their memory performance after 5 and 15 training days (initial training and overtraining, respectively) and following an emotional challenge (exposure to an open field). Our results showed that, compared to control quail, chronic stress impacted negatively spatial memory performances in stressed birds after initial training, but these differences were lowered after overtraining. Control birds seemed to shift from spatial to cue-based memory to solve the task across overtraining. However, an emotional challenge before testing reinstated the negative impact of chronic stress on spatial memory performances between the groups, revealing that chronic stress/overtraining did not eliminate the spatial memory and differences caused by stressors can reemerge depending on the individual's immediate psychological state. Contrary to spatial memory, cue-based memory was not affected in chronically stressed birds compared to control birds in any test occasion, confirming its resistance against the negative effects of chronic stress. Altogether these findings reveal a dynamic dialogue between stress, training level, and memory systems in birds.

Emotionality modulates the impact of chronic stress on memory and neurogenesis in birds.

Chronic stress is a strong modulator of cognitive processes, such as learning and memory. There is, however, great within-individual variation in how an animal perceives and reacts to stressors. These differences in coping with stress modulate the development of stress-induced memory alterations. The present study investigated whether and how chronic stress and individual emotionality interrelate and influence memory performances and brain neurogenesis in birds. For that, we used two lines of Japanese quail (Coturnix japonica) with divergent emotionality levels. Highly (E+) and less (E-) emotional quail were submitted to chronic unpredictable stress (CUS) for 3 weeks and trained in a spatial task and a discrimination task, a form of cue-based memory. E + and E- birds were also used to assess the impact of CUS and emotionality on neurogenesis within the hippocampus and the striatum. CUS negatively impacted spatial memory, and cell proliferation, and survival in the hippocampus. High emotionality was associated with a decreased hippocampal neurogenesis. CUS improved discrimination performances and favored the differentiation of newborn cells into mature neurons in the striatum, specifically in E+ birds. Our results provide evidence that CUS consequences on memory and neural plasticity depends both on the memory system and individual differences in behavior.

Research Note: Role of the hippocampus in spatial memory in Japanese quail.

The Japanese quail is a powerful model to characterize behavioral, physiological, and neurobiological processes in Galliformes. Behavioral tests have already been adapted for quail to assess memory systems, but despite the pivotal role of the hippocampus in this cognitive process, its involvement in spatial memory has not been demonstrated in this species. In this study, lesions were created in the hippocampus of Japanese quail, and both lesioned and control quail were tested for spatial and cue-based learning performances. These hippocampal lesions specifically impacted spatial learning performance, but spared learning performance when birds could solve the task using their cue-based memory. These findings, thus, highlight that the hippocampus plays a crucial role and is essential for spatial declarative memory. Future studies could aim to elucidate the cellular or molecular mechanisms involved in this form of memory.

Object and food novelty induce distinct patterns of c-fos immunoreactivity in amygdala and striatum in domestic male chicks (Gallus gallus domesticus).

Avoidance of novelty, termed neophobia, protects animals from potential dangers but can also impair their adaptation to novel environments or food resources. This behaviour is particularly well described in birds but the neurobiological correlates remain unexplored. Here, we measured neuronal activity in the amygdala and the striatum, two brain regions believed to be involved in novelty detection, by labelling the early gene c-fos following chicks exposure to a novel food (NF), a novel object (NO) or a familiar food (FF). NF and NO chicks showed significantly longer latencies to touch the food, less time eating and emitted more fear-vocalizations than control chicks. Latency to touch the food was also longer for NO than for NF chicks. Significantly higher densities of c-fos positive cells were present in all the nuclei of the arcopallium/amygdala of NF and NO chicks compared to FF chicks. Also, NO chicks showed higher positive cell densities than NF chicks in the posterior amygdaloid, the intermediate and the medial arcopallium. Exposure to novel food or object induced a similar increase in c-fos expression in the nucleus accumbens and the medial striatum. Our data provide evidence activation of the arcopallium/amygdala is specific of the type of novelty. The activation of striatum may be more related to novelty seeking.

Incidence and risk factors for gangrene in patients with systemic sclerosis from the EUSTAR cohort.

OBJECTIVE: In patients with SSc, peripheral vasculopathy can promote critical ischaemia and gangrene. The aim of this study was to investigate the prevalence, incidence and risk factors for gangrene in the EUSTAR cohort. METHODS: We included patients from the EUSTAR database fulfilling the ACR 1980 or the ACR/EULAR 2013 classification criteria for SSc, with at least one visit recording data on gangrene. Centres were asked for supplementary data on traditional cardiovascular risk factors. We analysed the cross-sectional relationship between gangrene and its potential risk factors by univariable and multivariable logistic regression. Longitudinal data were analysed by Cox proportional hazards regression. RESULTS: 1757 patients were analysed (age 55.9 [14.5] years, disease duration 7.9 [10.3] years, male sex 16.7%, 24.6% diffuse cutaneous subset [dcSSc]). At inclusion, 8.9% of patients had current or previous digital gangrene, 16.1% had current digital ulcers (DUs) and 42.7% had ever had DUs (current or previous). Older age, DUs ever and dcSSc were statistically significant risk factors for gangrene in the cross-sectional multivariable model. During a median follow-up of 13.1 months, 16/771 (0.9%) patients developed gangrene. All 16 patients who developed gangrene had previously had DUs and gangrene. Further risk factors for incident gangrene were the dcSSc subset and longer disease duration. CONCLUSION: In unselected SSc patients, gangrene occurs in about 9% of SSc patients. DUs ever and, to a lesser extent, the dcSSc subset are strongly and independently associated with gangrene, while traditional cardiovascular risk factors could not be identified as risk factors.

Brain mapping of the gonadotropin-inhibitory hormone-related peptide 2 with a novel antibody suggests a connection with emotional reactivity in the Japanese quail (Coturnix japonica, Temminck & Schlegel, 1849).

Gonadotropin-inhibitory hormone (GnIH) is a neuropeptide first discovered in the quail brain that is involved in the control of reproductive physiology and behaviors, and stress response. GnIH gene encodes a second peptide, GnIH-related peptide-2 (RP2), the distribution and function of which remain unknown. We therefore studied GnIH-RP2 distribution by immunohistochemistry using a novel antibody capable of discriminating between GnIH and GnIH-RP2. The overall distribution of GnIH-RP2 is similar to that of GnIH. The vast majority of labeled neurons is located in the paraventricular nucleus (PVN) of the hypothalamus. Labeling of fibers is conspicuous in the diencephalon, but present also in the mesencephalon and telencephalon. Several regions involved in the control of reproduction and stress response (the PVN, septum, bed nucleus of the stria terminalis and nucleus commissura pallii) showed a dense network of immunolabeled fibers. To investigate the potential function of GnIH-RP2 we compared its expression in two quail lines genetically selected for divergence in their emotional reactivity. A quantitative analysis in the above-mentioned brain regions showed that the density of fibers was similar in the two lines. However, the number of GnIH-RP2 labeled neurons was higher in the median portion of the PVN in birds with higher emotional reactivity. These results point to a possible involvement of GnRH-RP2 in modulating stress response and/or emotional reactivity.

A trait for a high emotionality favors spatial memory to the detriment of cue-based memory in Japanese quail.

Recent studies provided evidence that a personality trait such as a trait for a high or a low emotionality can either promotes or impairs learning and memory performances. This variability can be partly explained because this trait may have opposite effect on memory performances depending on the memory system involved. The present study investigated in Japanese quail the relationships between emotionality and two forms of memory, spatial- memory and cue-based memory. We showed that birds with a high emotionality trait (E+), compared with birds with a low emotionality trait (E-), reached slowly but more accurately the spatial location of a rewarded cup in an arena that contains 8 identical cups. Then a second cohort of E + and E- quails was trained to solve a dual spatial/cued task in which they could use either their spatial or cue-based memory. Whereas E + birds predominantly solved the task using their spatial memory, E- birds preferentially used their cue-based memory. These findings demonstrate that a trait for a high emotionality, can influence spatial memory performances but also contributes to favor the selection of this form of memory.

In situ anticaries efficacy of dentifrices with different formulations - A pooled analysis of results from three randomized clinical trials.

OBJECTIVES: Data generated from three similar in situ caries crossover studies presented the opportunity to conduct a pooled analysis to investigate how dentifrice formulations with different fluoride salts and combinations at concentrations of 1400-1450 ppm F, different abrasive systems and in some cases, carbomer (Carb), affect enamel caries lesion remineralization and fluoridation. METHODS: Subjects continuously wore modified partial dentures holding two gauze-covered partially-demineralized human enamel specimens for 14 days and brushed 2×/day with their assigned dentifrice: Study 1: sodium fluoride (NaF)/Carb/silica, NaF/silica, NaF + monofluorophosphate (MFP)/chalk; Study 2: NaF/Carb/silica, NaF + MFP/dical, amine fluoride (AmF)/silica; Study 3: NaF/Carb/silica, NaF + stannous fluoride (SnF2)/silica/hexametaphosphate (HMP). All studies included Placebo (0 ppm F) and/or dose-response controls (675 ppm F as NaF [675F-NaF]) ±Carb. Specimens were evaluated for percentage surface microhardness recovery (SMHR) and enamel fluoride uptake (EFU). RESULTS: All 1400-1450 ppm F dentifrices except NaF + SnF2/silica/HMP provided significantly greater lesion remineralization than Placebo (p < 0.0001): differences in SMHR ranged from 17.46% (NaF + MFP/dical) to 26.66% (AmF/silica). For EFU (back-transformed log EFU), all 1400-1450 ppm F dentifrices gave significant fluoride uptake compared to Placebo (p < 0.0001): increases in EFU ranged from 4.95 µg F/cm2 (NaF + SnF2/silica/HMP) to 16.32 µg F/cm2 (NaF/carb/silica). Dentifrices containing NaF or AmF as sole fluoride source provided the greatest remineralization and fluoridation; Carb addition did not alter fluoride efficacy; some excipients appeared to interfere with the cariostatic action of fluoride. Treatments were generally well-tolerated with ≤4 treatment-related adverse events per study. CONCLUSION: Commercially available fluoride dentifrices varied greatly in their ability to remineralize and fluoridate early caries lesions. CLINICAL SIGNIFICANCE: Fluoride dentifrices are the most impactful anticaries modality worldwide. While clinical caries trials have not consistently shown the superiority of one formulation over another, these findings using a sensitive in situ caries model indicated that dentifrices containing NaF or AmF as the sole fluoride source provided the greatest remineralization and fluoridation benefits.

Electrical properties of a liquid crystal dispersed in an electrospun cellulose acetate network.

Electro-optical devices that work in a similar fashion as PDLCs (polymer-dispersed liquid crystals), produced from cellulose acetate (CA) electrospun fibers deposited onto indium tin oxide coated glass and a nematic liquid crystal (E7), were studied. CA and the CA/liquid crystal composite were characterized by multiple investigation techniques, such as polarized optical microscopy, dielectric spectroscopy and impedance measurements. Dielectric constant and electric energy loss were studied as a function of frequency and temperature. The activation energy was evaluated and the relaxation time was obtained by fitting the spectra of the dielectric loss with the Havriliak-Negami functions. To determine the electrical characteristics of the studied samples, impedance measurements results were treated using the Cole-Cole diagram and the three-element equivalent model.

Dielectric properties of a bisimidazolium salt with dodecyl sulfate anion doped with carbon nanotubes.

A new bisimidazolium salt with dodecyl sulfate as counterion has been designed and prepared. This salt shows a SmA phase that is stable at room temperature. The new ionic liquid crystal (ILC) was characterized by 1H NMR, 13C NMR and IR spectroscopy. Its liquid crystalline properties were analyzed by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD) studies. The dielectric spectra of the ILC doped with different concentrations of carbon nanotubes (CNT) were recorded over a wide frequency and temperature range of 10-1 to 107 Hz and 293-338 K, respectively. The values of the activation energy were found in the range of 0.46-0.61 eV; the characteristic time was obtained by fitting the spectra of the dielectric loss with the Havriliak-Negami functions. As a result of doping the ILC with CNT, the electric conductivity increases significantly. Ionic conductivity is dominant and it was indirectly observed through the electrode polarization (EP) effect. The very high dielectric permittivity values and the decrease of the electric conductivity at low frequencies confirm the presence of EP.

Efficacy of an experimental 3% potassium nitrate mouthwash in providing long-term relief from dentin hypersensitivity: An 8-week randomized controlled study (Study 2).

PURPOSE: To evaluate the efficacy of an experimental mouthwash containing 3% potassium nitrate (KNO3) in the relief of dentin hypersensitivity when used as an adjunct to brushing with fluoride toothpaste compared with the use of the same toothpaste alone. METHODS: This was a randomized, two-treatment, examiner-blind, parallel-design single-center, 8-week study in healthy subjects with self-reported and clinically diagnosed dentin hypersensitivity. Subjects were randomized to receive either fluoride toothpaste plus 3.0% KNO2 mouthwash or the same fluoride toothpaste alone, and instructed to use their allocated treatment twice daily for the next 8 weeks. Dentin hypersensitivity was evaluated at baseline and following 4 and 8 weeks of treatment through assessment of responses to evaporative (air) and tactile stimuli [measured by the Schiff sensitivity scale/a visual rating scale (VRS) and tactile threshold, respectively], and using the Dentin Hypersensitivity Experience Questionnaire (DHEQ, a validated quality-of-life instrument for dentin hyper-sensitivity). RESULTS: A total of 135 subjects were randomized and all completed the study. Both treatment groups demonstrated statistically significant improvements in sensitivity from baseline for each clinical measure of sensitivity (P< 0.0001) at Week 4 and Week 8. The toothpaste plus mouthwash group showed greater reductions in sensitivity at both timepoints for all clinical measures; between-treatment differences were only statistically significant for responses to an evaporative (air) stimulus (Schiff sensitivity score and VRS) at Week 4. There was evidence of an improvement in dentin hypersensitivity-associated quality of life as measured by changes from baseline in several DHEQ parameters for both treatment groups, but there were no statistically significant differences between treatments. CLINICAL SIGNIFICANCE: Although in the current study adjunctive use of a 3% KNO2 mouthwash did not provide statistically significant improvements in dentin hypersensitivity for all clinical measures at all timepoints compared with use of fluoride toothpaste alone, the reductions in sensitivity observed in this study are compatible with the findings of a previous study that showed adjunctive use of a 3% KNO2 mouthwash to be effective in providing relief from dentin hypersensitivity after 8 weeks' twice-daily use.

Digital ulcers predict a worse disease course in patients with systemic sclerosis.

OBJECTIVE: Systemic sclerosis (SSc) is a systemic autoimmune disease with high morbidity and significant mortality. There is a great need of predictors that would allow risk stratification of patients with SSc and ultimately initiation of treatment early enough to ensure optimal clinical results. In this study, we evaluated whether a history of digital ulcers (HDU) at presentation may be a predictor of vascular outcomes and of overall clinical worsening and death in patients with SSc. METHODS: Patients from the EULAR Scleroderma Trials and Research (EUSTAR) database, satisfying at inclusion the 1980 American College of Rheumatology classification criteria for SSc, who had a follow-up of at least 3 years since baseline or who have died, were included in the analysis. HDU at presentation as a predictor of disease worsening or death was evaluated by Cox proportional hazards regression analysis. RESULTS: 3196 patients matched the inclusion criteria (male sex 13.2%, 33.4% diffuse subset). At presentation, 1092/3196 patients had an HDU (34.1%). In multivariable analysis adjusting for age, gender and all parameters considered potentially significant, HDU was predictive for the presence of active digital ulcers (DUs) at prospective visits (HR (95% CI)): 2.41 (1.91 to 3.03), p<0.001, for an elevated systolic pulmonary arterial pressure on heart ultrasound (US-PAPs):1.36 (1.03 to 1.80), p=0.032, for any cardiovascular event (new DUs, elevated US-PAPs or LV failure): 3.56 (2.26 to 5.62), p<0.001, and for death (1.53 (1.16 to 2.02), p=0.003). CONCLUSIONS: In patients with SSc, HDU at presentation predicts the occurrence of DUs at follow-up and is associated with cardiovascular worsening and decreased survival.

Yolk hormones influence in ovo chemosensory learning, growth, and feeding behavior in domestic chicks.

In this study, we assessed whether prenatal exposure to elevated yolk steroid hormones can influence in ovo chemosensory learning and the behavior of domestic chicks. We simulated a maternal environmental challenge by experimentally enhancing yolk progesterone, testosterone, and estradiol concentrations in hen eggs prior to incubation. The embryos from these hormones-treated eggs (HO) as well as sham embryos (O) that had received the vehicle-only were exposed to the odor of fish oil (menhaden) between embryonic Days 11 and 20. An additional group of control embryos (C) was not exposed to the odor. All chicks were tested following hatching for their feeding preferences between foods that were or were not odorized with the menhaden odor. In the 3-min choice tests, the behavior of O chicks differed significantly according to the type of food whereas C and HO chicks showed no preference between odorized and non-odorized food. Our result suggests weaker response in HO chicks. In addition, HO chicks showed impaired growth and reduced intake of an unfamiliar food on the 24-h time scale compared to controls. Our data suggest that embryonic exposure to increased yolk hormone levels can alter growth, chemosensory learning, and the development of feeding behaviors.

Artificially Increased Yolk Hormone Levels and Neophobia in Domestic Chicks.

In birds there is compelling evidence that the development and expression of behavior is affected by maternal factors, particularly via variation in yolk hormone concentrations of maternal origin. In the present study we tested whether variation in yolk hormone levels lead to variation in the expression of neophobia in young domestic chicks. Understanding how the prenatal environment could predispose chicks to express fear-related behaviors is essential in order to propose preventive actions and improve animal welfare. We simulated the consequences of a maternal stress by experimentally enhancing yolk progesterone, testosterone and estradiol concentrations in hen eggs prior to incubation. The chicks from these hormone-treated eggs (H) and from sham embryos (C) that received the vehicle-only were exposed to novel food, novel object and novel environment tests. H chicks approached a novel object significantly faster and were significantly more active in a novel environment than controls, suggesting less fearfulness. Conversely, no effect of the treatment was found in food neophobia tests. Our study highlights a developmental influence of yolk hormones on a specific aspect of neophobia. The results suggest that increased yolk hormone levels modulate specifically the probability of exploring novel environments or novel objects in the environment.

Emotionality modulates the effect of chronic stress on feeding behaviour in birds.

Chronic stress is a long-lasting negative emotional state that induces negative consequences on animals' psycho-physiological state. This study aimed at assessing whether unpredictable and repeated negative stimuli (URNS) influence feeding behaviour in quail. Sixty-four quail were exposed to URNS from day 17 to 40, while 64 quail were undisturbed. Two lines divergently selected on their inherent emotionality were used to assess the effect of genetic factors on the sensitivity to URNS. All quail were submitted to a sequential feeding procedure (using two diets of different energetic values) which placed them in a contrasting situation. Behavioural tests were performed to assess the emotional reactivity of the two lines. Results confirmed that differences exist between them and that their emotional reactivity was enhanced by URNS. Diet preferences, motivation and daily intake were also measured. URNS did not change the preferences for the hypercaloric diet compared to the hypocaloric diet in choice tests, but they reduced daily intakes in both lines. Motivations for each diet were differently affected by URNS: they decreased the motivation to eat the hypercaloric diet in quail selected for their low inherent fearfulness whereas they increased the motivation to eat the hypocaloric diet in quail selected for their high inherent fearfulness, which suggested a devaluation process in the former and a compensatory behaviour in the later. Growth was furthermore reduced and laying delayed by URNS in both lines. In conclusion, the exposure to URNS induced interesting changes in feeding behaviour added with an increase in emotional reactivity and an alteration of production parameters. This confirms that both lines of quail experienced a chronic stress state. However differences in feed motivation and emotional reactivity between lines under chronic stress suggested that they experienced different emotional state and use different ways to cope with it depending on their genetic background.

Effect of one week of stress on emotional reactivity and learning and memory performances in Japanese quail.

Chronic stress is known to induce long term alterations of emotional behaviours as well as cognitive performances leading thereby to welfare or husbandry problems. These stress-induced consequences are observed following long periods of stress lasting from several weeks to several years. The current study examined whether a shorter period of stress (one week) produced similar impairing effects. Two-week old Japanese quail were either submitted to a series of aversive events over consecutive 8 days, at unpredictable times each day (treated animals) or left undisturbed (controls). Following the treatment period, animals were weighed and basal as well as aversive events-induced levels of plasma corticosterone were quantified. Quail were also tested for emotional reactivity in three tests (the tonic immobility test, the hole-in-the-wall and novel object tests) and for spatial reference memory. Although there was no difference in corticosterone levels between the two groups, the treated animals had lower body weight than controls. Behavioural investigations after the treatment period did not reveal any difference between the groups in the three emotional reactivity tests. In the spatial task, treated quail displayed enhanced behavioural flexibility as revealed by their higher performances during the reversal phase of the task. The alteration of growth suggests that a short period of repetitive exposures to unpredictable aversive events can be perceived by quail as stressful. Such a stress period can improve spatial learning performances in quail supporting the critical role played by the duration of the stress period on cognitive performance.