Impact de l'expérience précoce sur le développement cérébral de l'agneau

National audienc

First evidence of neuronal connections between specific parts of the periaqueductal gray (PAG) and the rest of the brain in sheep: placing the sheep PAG in the circuit of emotion

International audienceThe periaqueductal gray (PAG) is a mesencephalic brain structure organised in subdivisions with specific anatomical connections with the rest of the brain. These connections support the different PAG functions and especially its role in emotion. Mainly described in territorial and predatory mammals, examination of the PAG connections suggests an opposite role of the ventral and the dorsal/lateral PAG in passive and active coping style, respectively. In mammals, the organisation of PAG connections may reflect the coping style of each species. Based on this hypothesis, we investigated the anatomical connections of the PAG in sheep, a gregarious and prey species. Since emotional responses expressed by sheep are typical of active coping style, we focused our interest on the dorsal and lateral parts of the PAG. After injection of fluorogold and fluororuby, the most numerous connections occurred with the anterior cingulate gyrus, the anterior hypothalamic region, the ventromedial hypothalamic nucleus and the PAG itself. Our observations show that the sheep PAG belongs to the neuronal circuit of emotion and has specific parts as in other mammals. However, unlike other mammals, we observed very few connections between PAG and either the thalamic or the amygdalar nuclei. Interestingly, when comparing across species, the PAG connections of sheep were noticeably more like those previously described in other social species, rabbits and squirrel monkeys, than those in territorial species, rats or cats

Comparative brain morphology of specimens with different adaptative behaviors the bongo, the Java deer mouse, the maki catta and the sea lion

International audienceOne aim of comparative neuroanatomy is to better understand brain function among species. It is tempting to try and explain brain differences throughout the animal kingdom by differences in adaptive behaviors as well as ecological factors. Based on this idea, we explored, with MRI, the brain morphology of three species with different sociality and predator avoidance (Bongo, Java deer mouse and Maki Catta). Brains were collected after death of natural causes and MR-imaged. Brain and body weights were collected, and volumes of brain were estimated after MRI segmentation. The brain-to-body weight ratio was close to 1 for the Java deer mouse (1.04%) and the maki catta (1.05%) but only 0.26% for the bongo. Encephalization quotients (EQ) were calculated using formulas defined for human (hEQ, constants 0.12 and 2/3; Cairó 2011, doi:10.3389/fnhum.2011.00108) and for dog (dEQ, constants 0.14 and 0.528; Saganuwan 2021, doi:10.1186/s13104-021-05638-0). Whatever the method, the Java deer mouse EQs were the smallest (hEQ=0.98; dEQ=0.88). The maki catta had a higher hEQ (1.23) than the bongo (1.14) whereas the order was reversed for the dEQ (maki catta dEQ=1.21; bongodEQ=1.96). These values are coherent with the idea that EQ is higher in prey species using active predator avoidance (bongo) and in social species (bongo and maki catta

Impact of early rearing experience on brain development in sheep infant.

Impact of early rearing experience on brain development in sheep infant. . New animal models to understand the brai

Are sheep really afraid of the wolf?

International audienceSheep are a high-olfactory sensitive species, this cue being crucial for social recognition (Hild et al. 2011) and predator avoidance (Gluesing et al. 1980). To protect themselves from predation, sheep are able to recognize cues of their predators. In a food-choice test, ewes chose to eat in the location without dog feces, this odour appeared to be repellent (Arnould et al. 1993). However, there is a trade-off between foraging and the risk of predation. We chose to test this trade-off. Our experimental design questions the motivation to eat in a context with a possible risk of predation. We hypothesize that olfactory stimuli with negative valence (wolf and cadaverine) will induce stress-like behaviors. 30 adult Ile de France ewes participated after one week of habituation to the experimental setup in the presence of four unfamiliar conspecifics. During a test, ewes entered an arena in which a plexiglas box contained the olfactory stimulus close to a bucket of pellets, for 5 minutes. The total number of vocalizations, the food intake and the food intake latency were recorded. In a first session, ewes were tested with water, 15µl orange essential oil (appetitive) and 3g of wolf feces (repulsive). In a second session, ewes were tested with water, 15g of wolf feces and 1ml of cadaverine. In this way, we tested the repulsive impact of predator feces and the putative repulsive effect of one its components. According to our hypothesis, we found a repulsive effect of wolf feces in each session by a decreased food intake (p<0.01, Friedmann test). Surprisingly, we didn't observe a repulsive effect of cadaverine even though two ewes expressed emetic behaviors. Moreover, the latency of food intake was lower for orange and wolf compared to water (p<0.05, Friedmann test) and the number of vocalizations was low and did not differ between stimuli. Taking into account all these results we are not able to conclude on the stressful impact of these olfactory stimuli of negative valence. Future work will use wireless EEG to investigate the underlying neural signatures of these stimuli

Comparative brain morphology of specimens with different adaptative behaviors the bongo, the Java deer mouse, the maki catta and the sea lion

International audienceOne aim of comparative neuroanatomy is to better understand brain function among species. It is tempting to try and explain brain differences throughout the animal kingdom by differences in adaptive behaviors as well as ecological factors. Based on this idea, we explored, with MRI, the brain morphology of three species with different sociality and predator avoidance (Bongo, Java deer mouse and Maki Catta). Brains were collected after death of natural causes and MR-imaged. Brain and body weights were collected, and volumes of brain were estimated after MRI segmentation. The brain-to-body weight ratio was close to 1 for the Java deer mouse (1.04%) and the maki catta (1.05%) but only 0.26% for the bongo. Encephalization quotients (EQ) were calculated using formulas defined for human (hEQ, constants 0.12 and 2/3; Cairó 2011, doi:10.3389/fnhum.2011.00108) and for dog (dEQ, constants 0.14 and 0.528; Saganuwan 2021, doi:10.1186/s13104-021-05638-0). Whatever the method, the Java deer mouse EQs were the smallest (hEQ=0.98; dEQ=0.88). The maki catta had a higher hEQ (1.23) than the bongo (1.14) whereas the order was reversed for the dEQ (maki catta dEQ=1.21; bongodEQ=1.96). These values are coherent with the idea that EQ is higher in prey species using active predator avoidance (bongo) and in social species (bongo and maki catta

Comparative brain morphology of specimens with different adaptative behaviors the bongo, the Java deer mouse, the maki catta and the sea lion

International audienceOne aim of comparative neuroanatomy is to better understand brain function among species. It is tempting to try and explain brain differences throughout the animal kingdom by differences in adaptive behaviors as well as ecological factors. Based on this idea, we explored, with MRI, the brain morphology of three species with different sociality and predator avoidance (Bongo, Java deer mouse and Maki Catta). Brains were collected after death of natural causes and MR-imaged. Brain and body weights were collected, and volumes of brain were estimated after MRI segmentation. The brain-to-body weight ratio was close to 1 for the Java deer mouse (1.04%) and the maki catta (1.05%) but only 0.26% for the bongo. Encephalization quotients (EQ) were calculated using formulas defined for human (hEQ, constants 0.12 and 2/3; Cairó 2011, doi:10.3389/fnhum.2011.00108) and for dog (dEQ, constants 0.14 and 0.528; Saganuwan 2021, doi:10.1186/s13104-021-05638-0). Whatever the method, the Java deer mouse EQs were the smallest (hEQ=0.98; dEQ=0.88). The maki catta had a higher hEQ (1.23) than the bongo (1.14) whereas the order was reversed for the dEQ (maki catta dEQ=1.21; bongodEQ=1.96). These values are coherent with the idea that EQ is higher in prey species using active predator avoidance (bongo) and in social species (bongo and maki catta

Does emotivity modulate stress effects on memory and brain plasticity in quail?

Does emotivity modulate stress effects on memory and brain plasticity in quail?. 35. International Ethological Conferenc

Selection of high-trait emotivity affects the volume of sensory and emotional-related brain regions in male Japanese quails

Japanese quails (Coturnix japonica) divergently selected based on their behavior during a tonic immobility test are an excellent model to study the link between brain morphology and behavior expression. The LTI (Long Tonic Immobility) and STI (Short Tonic Immobility) quail lines differ in their level of emotivity, with LTI quails being selected for their high-trait emotivity. Here, comparing the brain regions of the LTI and STI lines of male Japanese quails, we test the hypothesis that this divergent selection could have influenced brain anatomy, in particular, those regions involved in sensory and emotional processing. The heads of twenty, 10 weeks old male Japanese quails (10 STI and 10 LTI) were imaged ex-vivo using ultra high-resolution (11.7 Tesla) magnetic resonance imaging. The resulting images were used to create a population-averaged quail brain template and manually segmented 3D whole-brain atlas (openly available: https://doi.org/10.5281/zenodo.4700522). The atlas is composed of 191 brain regions, the ventricular system, pineal and pituitary glands. Thanks to this atlas, an exploratory analysis was conducted to compare brain regions between the two lines: the relative volumes of 33 regions were impacted (with 24 larger relative volumes being found in STI). This demonstrates for the first time in male Japanese quail that genetic selection for a specific emotional behavior (tonic immobility) modifies the anatomy of brain regions involved in sensory and emotional processing