0000000000322742
AUTHOR
Guillaume Ferreira
Neural activation induced by an odour mixture perceived elementally or configurally by the newborn rabbit
National audience; Perception of odours plays a crucial role in mammals facilitating interindividual communication, food choice and detection of danger, even from early in life (e.g. mother-young communication). However, little is known about the brain processing and perception of odorants in mixtures, which is by far the more common situation in life. To better understand how the brain processes odorants in mixtures, we used the newborn rabbit as a model. Rabbit pups display a clear sucking behaviour in response to the mammary pheromone (MP, the single molecule 2MB2) carried in the milk of lactating rabbit females. The MP also promotes associative conditioning and very rapid acquisition of…
The endocannabinoid system controls food intake via olfactory processes
Comment in Sensory systems: the hungry sense. [Nat Rev Neurosci. 2014] Inhaling: endocannabinoids and food intake. [Nat Neurosci. 2014]; International audience; Hunger arouses sensory perception, eventually leading to an increase in food intake, but the underlying mechanisms remain poorly understood. We found that cannabinoid type-1 (CB1) receptors promote food intake in fasted mice by increasing odor detection. CB1 receptors were abundantly expressed on axon terminals of centrifugal cortical glutamatergic neurons that project to inhibitory granule cells of the main olfactory bulb (MOB). Local pharmacological and genetic manipulations revealed that endocannabinoids and exogenous cannabinoid…
Causal Link between n-3 Polyunsaturated Fatty Acid Deficiency and Motivation Deficits
International audience; Reward-processing impairment is a common symptomatic dimension of several psychiatric disorders. However, whether the underlying pathological mechanisms are common is unknown. Herein, we asked if the decrease in the n-3 polyunsaturated fatty acid (PUFA) lipid species, consistently described in these pathologies, could underlie reward-processing deficits. We show that reduced n-3 PUFA biostatus in mice leads to selective motivational impairments. Electrophysiological recordings revealed increased collateral inhibition of dopamine D2 receptor-expressing medium spiny neurons (D2-MSNs) onto dopamine D1 receptor-expressing MSNs in the nucleus accumbens, a main brain regio…
Evidence of neonatal memory of odor configuration
The perception of some mixtures of odorants engages configural abilities, i.e. the perception of these mixtures as single odor objects. For instance, data in human adults demonstrated that a mixture of two odorants (AB), one smelling like strawberry and the other like caramel, generates the configural perception of the odor of pineapple (Le Berre et al., 2008; Barkat et al., 2012). Configural processing may be adaptive also for young organisms, to which rapid extraction of chemical information from the maternal environment, highly complex, is a prerequisite to survival. Thus, results in newborn rabbits suggest the perception of a unique odor in the AB mixture (smelling like configural pinea…
Sensory preconditioning in newborn rabbits: from common to distinct odor memories.
Brief Communication; International audience; This study evaluated whether olfactory preconditioning is functional in newborn rabbits and based on joined or independent memory of odorants. First, after exposure to odorants A+B, the conditioning of A led to high responsiveness to odorant B. Second, responsiveness to B persisted after amnesia of A. Third, preconditioning was also functional with two overlapping pairs of odorants (A+B and B+C) and amnesia of one odorant did not affect memory of the others. Thus, incidental pairing of odorants allows reinforcement of one odorant to implicitly reinforce the others, the bond then vanishes, and the memory of each element becomes independent.
Neonatal representation of odour objects: distinct memories of the whole and its parts
Extraction of relevant information from highly complex environments is a prerequisite to survival. Within odour mixtures, such information is contained in the odours of specific elements or in the mixture configuration perceived as a whole unique odour. For instance, an AB mixture of the element A (ethyl isobutyrate) and the element B (ethyl maltol) generates a configural AB percept in humans and apparently in another species, the rabbit. Here, we examined whether the memory of such a configuration is distinct from the memory of the individual odorants. Taking advantage of the newborn rabbit's ability to learn odour mixtures, we combined behavioural and pharmacological tools to specifically…
Differential memory persistence of odor mixture and components in newborn rabbits: competition between the whole and its parts
Interacting with the mother during the daily nursing, newborn rabbits experience her body odour cues. In particular, the mammary pheromone (MP) contained in rabbit milk triggers the typical behaviour which helps to localize and seize the nipples. It also promotes the very rapid appetitive learning of simple or complex stimuli (odorants or mixtures) through associative conditioning. We previously showed that 24h after MP-induced conditioning to odorants A (ethyl isobutyrate) or B (ethyl maltol), newborn rabbits perceive the AB mixture in a weak configural way, i.e. they perceive the odour of the AB configuration in addition to the odours of the elements. Moreover, after conditioning to the m…
Elemental or configural perception of an odour mixture induces differences in neural activation in the newborn rabbit
International audience
Perinatal high-fat diet increases hippocampal vulnerability to the adverse effects of subsequent high-fat feeding
Epidemiological observations report an increase in fat consumption associated with low intake of n-3 relative to n-6 polyunsaturated fatty acids (PUFAs) in women of childbearing age. However, the impact of these maternal feeding habits on cognitive function in the offspring is unknown. This study aims to investigate the impact of early exposure to a high-fat diet (HFD) with an unbalanced n-6/n-3 PUFAs ratio on hippocampal function in adult rats. Furthermore, we explored the effects of perinatal HFD combined with exposure to HFD after weaning. Dams were fed a control diet (C, 12% of energy from lipids, n-6/n-3 PUFAs ratio: 5) or HFD (HF, 39% of energy from lipids, n-6/n-3 PUFAs ratio: 39) th…
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