Biology subjects

Courtiol, E.

Publications and source records attributed to Courtiol, E..

3 recordsLinked to original sources

bioRxiv2025

Odor-evoked respiratory responses throughout development in sighted and blind mice

Congenital blindness affects olfactory function depending on developmental stage. However, when studying the ontogeny of olfactory abilities, not all behaviors are expressed at every age making the longitudinal comparisons difficult. Odor-evoked respiratory responses, which are unlearned and do not require complex motor coordination, may serve as sensitive measures of olfactory abilities throughout ontogeny. Using a non-invasive measure of respiration in an olfactory perceptual paradigm, we assessed odor-evoked respiratory responses in a model of congenital blindness at 3 ages, infant, juvenile and adult, in the same mice and in both males and females. We demonstrated the differential outcome of two respiratory parameters (i.e. frequency and amplitude) in a mouse model of congenital blindness. We showed that blind mice have similar olfactory abilities than sighted mice throughout ontogeny but display enhanced sniffing frequency and amplitude, starting at the juvenile age for the latter one, that may help them better explore their environment. We also demonstrated that respiratory frequency is a robust index of age and of olfactory detection, habituation and discrimination at all ages. On the other side, respiratory amplitude does not provide a proxy of olfactory performance at all ages, however, it does highlight differences between sexes and phenotypes associated with visual deprivation. To conclude, our data highlight that respiratory parameters can be used as a complementary approach to assess olfactory performance throughout development and provide an index of olfactory plasticity.

neuroscience↗

bioRxiv2023

State-dependent alteration of respiration in a rat model of Parkinson disease

Parkinson disease (PD) is the second most frequent neurodegenerative disorder. Besides major deficits in motor coordination, patients may also display sensory and cognitive impairments, which are often overlooked despite being inherently part of the PD symptomatology. Amongst those symptoms, respiration, a key mechanism involved in the regulation of multiple physiological and neuronal processes, appears to be altered. Importantly, breathing patterns are highly correlated with the animals behavioral states, and although respiration has been investigated in different models of PD, no study has yet taken into consideration the potential impact of behavioral state on respiration deficits in these models. To explore this variable, we first characterized the respiratory parameters in a neurotoxin-induced rat model of PD (6-OHDA) across different vigilance states: sleep, quiet waking and exploration. We noted a significantly higher respiratory frequency in 6-OHDA rats during quiet waking compared to Sham rats. A higher respiratory amplitude was also observed in 6-OHDA rats during both quiet waking and exploration. No effect of the treatment was noted during sleep. Given the relation between respiration and olfaction and the presence of olfactory deficits in PD patients, we then investigated the odor-evoked sniffing response in PD rats, using an odor habituation/cross-habituation paradigm. No substantial differences were observed in olfactory abilities between the two groups, as assessed through sniffing frequency. These results corroborate the hypothesis that respiratory impairments in 6-OHDA rats are vigilance-dependent. Our results also shed light on the importance of considering the behavioral state as an impacting factor when analyzing respiration. HighlightsO_LISpecific respiratory patterns associated to different vigilance states C_LIO_LISpecific alteration of respiration during quiet waking in a rodent model of PD C_LIO_LIPreserved olfactory abilities as assessed through sniffing in a rodent model of PD C_LI

neuroscience↗

bioRxiv2022

Sniffing response to an odor through development in rats: modulatory role of repetition and association with an aversive event

Sniffing has proven to be a useful behavioral readout for assessing olfactory performance in adult rats. However, little is known about how sniffing response changes through ontogeny. This study thus aimed at characterizing respiratory response to an odor through development in rats using paradigms applicable to both young pups and adults. We first analyzed the sniffing response to the arrival of a novel neutral odor. Then the value of the odor was changed through either its repeated presentation (odor habituation), or its association with a foot-shock resulting in odor fear. In the habituation task, we found that at the three ages, the first presentation of the novel odor induced a clear sniffing response but the peak respiratory frequency was higher in adults than in juveniles and infants. When the odor was presented repeatedly, the sniffing response gradually faded. This habituation of the response took more trials as the animals age increases. In the fear conditioning task, the odor induced an increase in respiratory rate that persisted until the end of the session in adults and infants, while it faded rapidly in juveniles. When the odor was explicitly unpaired with the foot-shock, at the three ages the respiratory response to the odor lasted less over the session than in the paired condition. Finally, we observed that shock delivery induced a similar respiratory response at the three ages in paired and unpaired condition. Collectively these data show that sniffing response constitutes a faithful index to assess rats olfactory abilities through ontogeny.

neuroscience↗