Search results for "Neural"
showing 10 items of 2783 documents
Neurotoxic effects of ochratoxin A on the subventricular zone of adult mouse brain
2014
Ochratoxin A (OTA), a mycotoxin that was discovered as a secondary metabolite of the fungal species Aspergillus and Penicillium, is a common contaminant in food and animal feed. This mycotoxin has been described as teratogenic, carcinogenic, genotoxic, immunotoxic and has been proven a potent neurotoxin. Other authors have previously reported the effects of OTA in different structures of the central nervous system as well as in some neurogenic regions. However, the impact of OTA exposure in the subventricular zone (SVZ) has not been assessed yet. To elucidate whether OTA affects neural precursors of the mouse SVZ we investigated, in vitro and in vivo, the effects of OTA exposure on the SVZ …
Just noticeable differences in component concentrations modify the odor quality of a blending mixture.
2008
International audience; The odors we perceive are mainly the result of mixtures of odorants that, however, are commonly perceived as single undivided entities; nevertheless, the processes involved remain poorly explored. It has been recently reported that perceptual blending based on configural olfactory processing can cause odorant mixtures to give rise to an emergent odor not present in the components. The present study examined whether specific component proportions are required to elicit an emergent odor. Starting from the composition of a ternary target mixture in which an emergent pineapple odor was perceived, 4 concentration levels of each component were chosen to elicit just noticea…
Characterization of somatostatin- and cholecystokinin-immunoreactive periglomerular cells in the rat olfactory bulb.
2005
Periglomerular cells (PG) are interneurons of the olfactory bulb (OB) that modulate the first synaptic relay of the olfactory information from the olfactory nerve to the dendrites of the bulbar principal cells. Previous investigations have pointed to the heterogeneity of these interneurons and have demonstrated the presence of two different types of PG. In the rat OB, type 1 PG receive synaptic contacts from the olfactory axons and are γ-aminobutyric acid (GABA)-ergic, whereas type 2 PG do not receive synaptic contacts from the olfactory axons and are GABA immunonegative. In this study, we analyze and characterize neurochemically a group of PG that has not been previously classified either …
PSA Depletion Induces the Differentiation of Immature Neurons in the Piriform Cortex of Adult Mice
2021
Immature neurons are maintained in cortical regions of the adult mammalian brain. In rodents, many of these immature neurons can be identified in the piriform cortex based on their high expression of early neuronal markers, such as doublecortin (DCX) and the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). This molecule plays critical roles in different neurodevelopmental events. Taking advantage of a DCX-CreERT2/Flox-EGFP reporter mice, we investigated the impact of targeted PSA enzymatic depletion in the piriform cortex on the fate of immature neurons. We report here that the removal of PSA accelerated the final development of immature neurons. This was revealed by a h…
Perceptual blending in odor mixtures depends on the nature of odorants and human olfactory expertise.
2012
International audience; Our olfactory system is confronted with complex mixtures of odorants, often recognized as single entities due to odor blending (e.g., coffee). In contrast, we are also able to discriminate odors from complex mixtures (e.g., off-odors). Therefore, the olfactory system is able to engage either configural or elemental processes when confronted with mixtures. However, the rules that govern the involvement of these processes during odor perception remain poorly understood. In our first experiment, we examined whether simple odorant mixtures (binary/ternary) could elicit configural perception. Twenty untrained subjects were asked to evaluate the odor typicality of mixtures…
Neural Substrate to Associate Odorants and Pheromones: Convergence of Projections from the Main and Accessory Olfactory Bulbs in Mice
2012
In rodents olfactory stimuli are essential for socio-sexual behaviour. Volatile stimuli mainly activate the main olfactory system, whereas non-volatile ones, some of them considered as pheromones, activate the accessory olfactory system. Traditionally, it has been considered that the efferent projections of the main and the accessory olfactory bulbs innervate different telencephalic areas. Recent studies performed in rats and mice have challenged this view. In this work we explore in mice, through the use of anterograde tracer injections in the olfactory bulbs, the brain centres where olfactory and vomeronasal information might converge.
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 …
Nitric oxide synthase containing periglomerular cells are GABAergic in the rat olfactory bulb.
2003
In the olfactory glomeruli of the rat olfactory bulb, there is a population of periglomerular cells (PG) that contains the neuronal isoform of the nitric oxide synthase (nNOS). To date, these PG have not been characterized neurochemically and it has not been determined whether they are type 1 (GABAergic PG that receive synaptic contacts from the olfactory axons) or type 2 PG (non-GABAergic PG that do not receive synapses from the olfactory axons). Combining pre-embedding NADPH-diaphorase histochemistry and post-embedding immunoperoxidase detection of GABA, we demonstrate that nNOS-containing PG are GABAergic and therefore, belong to the type 1 PG. The possible actions of nitric oxide in the…
The Assessment of Risk Factors for Long-term Survival Outcome in ypN0 Patients With Rectal Cancer After Neoadjuvant Therapy and Radical Anterior Rese…
2021
Abstract Background The main negative prognostic factors in patients with rectal cancer after radical treatment include regional lymph node involvement, lymphovascular invasion, and perineural invasion. However, some patients still develop cancer recurrence despite the absence of the above risk factors. The aim of the study was to assess clinicopathological factors influencing long-term oncologic outcomes in ypN0M0 rectal cancer patients after neoadjuvant therapy and radical anterior resection. Methods A retrospective survival analysis was performed on a group of 195 patients. We assessed clinicopathological factors which included tumor regression grade, number of lymph nodes in the specime…
Detection of postoperative plasma circulating tumour DNA and lack of CDX2 expression as markers of recurrence in patients with localised colon cancer
2020
BACKGROUND: Colon cancer (CC) is a heterogeneous disease. Novel prognostic factors beyond pathological staging are required to accurately identify patients at higher risk of relapse. Integrating these new biological factors, such as plasma circulating tumour DNA (ctDNA), CDX2 staining, inflammation-associated cytokines and transcriptomic consensus molecular subtypes (CMS) classification, into a multimodal approach may improve our accuracy in determining risk of recurrence.; METHODS: One hundred and fifty patients consecutively diagnosed with localised CC were prospectively enrolled in our study. ctDNA was tracked to detect minimal residual disease by droplet digital PCR. CDX2 expression was…