Search results for "Olfactory memory"

Chronic restraint stress and chronic corticosterone treatment modulate differentially the expression of molecules related to structural plasticity in…

2004

Stress and stress-related hormones induce structural changes in neurons of the adult CNS. Neurons in the hippocampus, the amygdala and the prefrontal cortex undergo neurite remodeling after chronic stress. In the hippocampus some of these effects can be mimicked with chronic administration of adrenal steroids. These changes in neuronal structure may be mediated by certain molecules related to plastic events such as the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). The expression of PSA-NCAM persists in the adult hippocampus and it is up-regulated after chronic stress. The piriform cortex also displays considerable levels of PSA-NCAM during adulthood and indirect evide…

Acute effects of 1,1,1-trichloroethane on human olfactory functioning.

2004

Background Animal experiments indicate that 1,1,1-trichloroethane can cause degeneration of the olfactory epithelium. The effects of 1,1,1-trichloroethane on human odor perception still have not been investigated. The goal of this study was to learn more about acute effects of 1,1,1-trichloroethane. Methods Twelve healthy, nonsmoking students were exposed to 200 and 20 ppm (control) 1,1,1-trichloroethane in an exposure chamber for 4 hours according to a crossover design. Olfactory functioning was investigated with the Sniffin’ Sticks. The test includes the determination of the detection threshold for n-butanol and an odor identification test. Results After 1 hour of exposure to 200 ppm 1,1,…

Bilateral olfactory deprivation reveals a selective noradrenergic regulatory input to the olfactory bulb.

2001

Unilateral olfactory deprivation in the rat induces changes in the catecholaminergic system of the olfactory bulb. Nevertheless, evidence suggests that unilateral deprivation does not fully prevent stimulation of the deprived bulb. The present report analyses the response of the catecholaminergic system of the olfactory bulb in fully deprived rats obtained by bilateral naris occlusion. The complete deprivation produces more rapid and dramatic changes in both the intrinsic and extrinsic catecholaminergic systems of the olfactory bulb. Intrinsic responses involve a rapid decrease in dopamine-containing cells to about 25% of controls, correlated with a decreased Fos expression in juxtaglomerul…

Modifications de l’olfaction au cours du vieillissement et de certaines pathologies neurodégénératives : mise au point

2015

Olfaction is a complex sensory system, and increasing interest is being shown in the link between olfaction and cognition, notably in the elderly. In this literature review, we revisit the specific neurophysiological features of the olfactory system and odorants that lead to a durable olfactory memory and an emotional memory, for which the implicit component produces subconscious olfactory conditioning. Olfaction is known to affect cognitive abilities and mood. We also consider the impairment of olfactory function due to ageing and to neurodegenerative diseases, in particular Alzheimer's disease and Parkinson's disease, through anatomopathological changes in the peripheral and central olfac…

Chemosensory Function of the Amygdala

2010

The chemosensory amygdala has been traditionally divided into two divisions based on inputs from the main (olfactory amygdala) or accessory (vomeronasal amygdala) olfactory bulbs, supposedly playing different and independent functional roles detecting odors and pheromones, respectively. Recently, there has been increased anatomical evidence of convergence inputs from the main and accessory bulbs in some areas of the amygdala, and this is correlated with functional evidence of interrelationships between the olfactory and the vomeronasal systems. This has lead to the characterization of a third division of the chemosensory amygdala, the mixed chemosensory amygdala, providing a new perspective…

Sexual pheromones and the evolution of the reward system of the brain: the chemosensory function of the amygdala.

2008

The amygdala of all tetrapod vertebrates receives direct projections from the main and accessory olfactory bulbs, and the strong similarities in the organization of these projections suggest that they have undergone a very conservative evolution. However, current ideas about the function of the amygdala do not pay sufficient attention to its chemosensory role, but only view it as the core of the emotional brain. In this study, we propose that both roles of the amygdala are intimately linked since the amygdala is actually involved in mediating emotional responses to chemical signals. The amygdala is the only structure in the brain receiving pheromonal information directly from the accessory …

Prenatal and Postnatal Human Olfactory Development: Influences on Cognition and Behavior

2015

Sensory preconditioning in newborn rabbits: from common to distinct odor memories.

2013

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.