Biology subjects

Masson, R.

Publications and source records attributed to Masson, R..

6 recordsLinked to original sources

bioRxiv2026

Sex difference in rat ventilatory response and pulmonary vascular resistance

The aim of this study was to investigate possible sex difference in rat ventilation and pulmonary vascular resistance. Experiments were done on 8 week-old 7 Wistar female and 7 male rats. Under anesthesia, the trachea was connected to a spirometer for measurement of the respiration rate (RR) and, normalized to weight, the tidal volume (Vt) and minute ventilation (VE). Responses to hypoxia/hypercapnia and hypoxia/normocapnia were tested by 1 min respiration in a 20 mL-closed circuit without and with CO2 trapping. After euthanasia, blood was collected for hematocrit, the pulmonary circulation was perfused on isolated lungs by a physiological solution at 10-40 mmHg pressure to determine the pressure-resistance curve, and the Fulton ratio (right ventricle/left ventricle+Septum weight ratio) was calculated. Data were compared by Mann-Whitney test and, for pressure-resistance curves, by non linear regression and F test. Female weight (226{+/-}9.6g) was significantly lower than males ones (356{+/-}11.7g). In normoxia/normocapnia, RR was 57{+/-}4.0 and 59{+/-}4.2 min-1, Vt/weight was 1.6{+/-}0.2 and 1.5{+/-}0.2 mL.100g-1, and VE/weight was 89{+/-}11 and 90{+/-}16 mL. min-1.100g-1 in female and male rats. Acute hypoxia/hypercapnia and hypoxia/normocapnia significantly increased ventilation. Whatever the conditions, no sex difference were found. Total pulmonary vascular resistance curve was significantly higher in males, whereas the Fulton ratio was similar in females (0.29{+/-}0.02) and males (0.28{+/-}0.03), as was the hematocrit. In conclusion, no sex difference was identified in the ventilatory response of rats. By contrast, pulmonary vascular resistance was significantly higher in males, without right ventricular hypertrophy.

physiology↗

bioRxiv2025

Tinnitus perception is linked to arousal system dysfunction

Tinnitus, the perception of sound in the absence of an external source, affects 14% of the population and is often associated with concentration and emotional difficulties. However, the characterization of the associated cognitive difficulties remains unclear. We hypothesize that attentional complaints are due to a dysfunction of the exogenous or endogenous orientation of attention, or of the arousal system. In this study, 200 participants (100 with chronic tinnitus and 100 matched controls) completed a battery of cognitive tasks assessing attention, alertness and executive functions, including the Attentional Network Task (ANT), Sustained Attention to Response Task (SART) with mind wandering evaluations, Stroop, and Trail Making Test. Tinnitus comorbidities, including hearing loss, sleep quality, anxiety, and hyperacusis were controlled. The results showed that individuals with tinnitus had a reduced sensitivity to alert signals, and lower sustained attention abilities, both suggesting lower levels of arousal. Mind-wandering analyses revealed fewer planning-related thoughts in the tinnitus group, suggesting higher needed cognitive resources to perform the task. Contrary to prior findings, we found no evidence of deficits in executive functioning specific to tinnitus; rather, executive impairments were associated with hearing loss and sleep disturbances. Overall, these findings support the hypothesis that tinnitus is linked to a dysfunction in the arousal system--likely involving the locus coeruleus-noradrenergic network. This work proposes a new theoretical framework implicating arousal dysregulation as a core mechanism in tinnitus-related cognitive complaints. Significance StatementTinnitus, the perception of sound without an external source, affects millions worldwide and is often accompanied by concentration difficulties. By rigorously controlling for hearing loss, sleep deprivation, and anxiety, we isolate the core cognitive changes linked to tinnitus itself. Our study reveals that attentional deficits in tinnitus primarily arise from dysregulation in the brains arousal system. We propose a novel integrative framework in which arousal system dysfunction underlies the cognitive and emotional symptoms associated with tinnitus, providing a new perspective for understanding the complex interactions between attention, sleep, and anxiety in this condition.

neuroscience↗

bioRxiv2021

Increase of both bottom-up and top-down attentional processes in high dream recallers

Event-related potentials (ERPs) associated with the involuntary orientation of (bottom-up) attention towards an unexpected sound are of larger amplitude in high dream recallers (HR) than in low dream recallers (LR) during passive listening, suggesting different attentional functioning. We measured bottom-up and top-down attentional performance and their cerebral correlates in 18 HR (11 women, age = 22.7 {+/-} 4.1 years, dream recall frequency = 5.3 {+/-} 1.3 days with a dream recall per week) and 19 LR (10 women, age = 22.3, DRF = 0.2 {+/-}0.2) using EEG and the Competitive Attention Task. Between-group differences were found in ERPs but not in behavior. The results confirm that HR present larger ERPs to distracting sounds than LR during active listening, suggesting enhanced bottom-up processing of irrelevant sounds. HR also presented a larger contingent negative variation during target expectancy and a larger P3b response to target sounds than LR, speaking for an enhanced recruitment of top-down attention. Enhancement of both top-down and bottom-up processes in HR leads to an apparently preserved attentional balance since similar performance were observed in the two groups. Therefore, different neurophysiological profiles can result in similar cognitive performance, with some profiles possibly costlier in term of resource/energy consumption.

neuroscience↗

bioRxiv2019

Attentional alterations in migraine: a behavioral and M/EEG study

AO_SCPLOWBSTRACTC_SCPLOWO_ST_ABSObjectivesC_ST_ABSTo evaluate alterations of top-down and/or bottom-up attention in migraine and their cortical underpinnings. Methods19 migraineurs between attacks and 19 matched control participants performed a task evaluating jointly top-down and bottom-up attention, using visually-cued target sounds and unexpected task-irrelevant distracting sounds. Behavioral responses and MEG/EEG were recorded. Event-related potentials and fields (ERPs/ERFs) were processed and source reconstruction was applied to ERFs. ResultsAt the behavioral level, neither top-down nor bottom-up attentional processes appeared to be altered in migraine. However, migraineurs presented heightened evoked responses following distracting sounds (orienting component of the N1 and Re-Orienting Negativity, RON) and following target sounds (orienting component of the N1), concomitant to an increased recruitment of the right temporo-parietal junction. They also displayed an increased effect of the cue informational value on target processing resulting in the elicitation of a negative difference (Nd). ConclusionsMigraineurs appear to display increased bottom-up orienting response to all incoming sounds, and an enhanced recruitment of top-down attention. SignificanceThe interictal state in migraine is characterized by an exacerbation of the orienting response to attended and unattended sounds. These attentional alterations might participate to the peculiar vulnerability of the migraine brain to all incoming stimuli. HO_SCPLOWIGHLIGHTSC_SCPLOWO_LIMigraineurs performed as well as healthy participants in an attention task. C_LIO_LIHowever, EEG markers of both bottom-up and top-down attention are increased. C_LIO_LIMigraine is also associated with a facilitated recruitment of the right temporo-parietal junction. C_LI

neuroscience↗

bioRxiv2018

What is in Your Gamma? Activation of The Ventral Fronto-Parietal Attentional Network in Response to Distracting Sounds

Auditory attention operates through top-down (TD) and bottom-up (BU) mechanisms that are supported by dorsal and ventral brain networks, respectively, with the main overlap in the lateral prefrontal cortex (lPFC). A good TD/BU balance is essential to be both task-efficient and aware of our environment, yet it is rarely investigated. Oscillatory activity is a novel method to probe the attentional dynamics with evidence that gamma activity (>30Hz) could signal BU processing and thus would be a good candidate to support the activation of the ventral BU network. MEG data were collected from 21 young adults performing the Competitive Attention Task which enables simultaneous investigation of BU and TD attentional mechanisms. Distracting sounds elicited an increase in gamma activity in regions of the BU ventral network. TD attention modulated these gamma responses in regions of the inhibitory cognitive control system: the medial prefrontal and anterior cingulate cortices. Finally, distracting-sound-induced gamma activity was synchronous between the auditory cortices and several distant brain regions, notably the lPFC. We provide novel insight into the role of gamma activity (1) in supporting the activation of the BU ventral network, and (2) in subtending the TD/BU attention balance in the prefrontal cortex.

neuroscience↗

bioRxiv2018

Fronto-central P3a to distracting sounds: an index of their arousing properties

The P3a observed after novel events is an event-related potential comprising an early fronto-central phase and a late fronto-parietal phase. It has classically been considered to reflect the attention processing of distracting stimuli. However, novel sounds can lead to behavioral facilitation as much as behavioral distraction. This illustrates the duality of the orienting response which includes both an attentional and an arousal component. Using a paradigm with visual or auditory targets to detect and irrelevant unexpected distracting sounds to ignore, we showed that the facilitation effect by distracting sounds is independent of the target modality and endures more than 1500 ms. These results confirm that the behavioral facilitation observed after distracting sounds is related to an increase in unspecific phasic arousal on top of the attentional capture. Moreover, the amplitude of the early phase of the P3a to distracting sounds positively correlated with subjective arousal ratings, contrary to other event-related potentials. We propose that the fronto-central early phase of the P3a would index the arousing properties of distracting sounds and would be linked to the arousal component of the orienting response. Finally, we discuss the relevance of the P3a as a marker of distraction.

neuroscience↗