Biology subjects

Messaoudi, B.

Publications and source records attributed to Messaoudi, B..

4 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

Distinct brain networks for remote episodic memory depending on content and emotional value

The mechanisms that underlie the storage of old nontraumatic episodic memories remain enigmatic because of the difficulty in modelling this particular type of memory in humans and animals. Episodic memories combine incidental and occasional "What-Where-When/In which context" multisensory information and can be stored for long periods of time. Here, using a task in rodents that models human episodic memory, including odour/place/context components, we applied advanced behavioural and computational analyses and brain imaging of c-Fos and Zif268 to characterize remote episodic memories and their engrams for the first time. We show that the content and accuracy of memories vary across individuals and depend on the emotional relationship with odours experienced during episodes. Activated brain networks reflect the nature and content of remote episodic memories and their transformation over time, and emotional cortico-hippocampal networks play critical roles in maintaining vivid memories.

neuroscience↗

bioRxiv2020

Respiration and brain neural dynamics associated with interval timing during odor fear learning in rats

In fear conditioning, where a conditioned stimulus predicts the arrival of an aversive stimulus, the animal encodes the time interval between the two stimuli. Freezing, the most used index to assess learned fear, lacks the temporal resolution required to investigate interval timing at the early stages of learning. Here we monitored respiration to visualize anticipatory behavioral responses in an odor fear conditioning in rats, while recording theta (5-15Hz) and gamma (40-80Hz) brain oscillatory activities in the medial prefrontal cortex (mPFC), basolateral amygdala (BLA), dorsomedial striatum (DMS) and olfactory piriform cortex (PIR). We investigated the temporal patterns of respiration frequency and of theta and gamma activity power during the odor-shock interval. We found that akin to respiration patterns, theta temporal curves were modulated by the duration of the odor-shock interval in the four recording sites, and respected scalar property in mPFC and DMS. In contrast, gamma temporal curves were modulated by the interval duration only in the mPFC, and in a manner that did not respect scalar property. This suggests a preferential role for theta rhythm in interval timing. In addition, our data bring the novel idea that the respiratory rhythm might take part in the setting of theta activity dynamics.

neuroscience↗