Biology subjects

Tagliabue, M.

Publications and source records attributed to Tagliabue, M..

3 recordsLinked to original sources

bioRxiv2023

Subchronic alteration of vestibular hair cells in mice: implications for multisensory gaze stabilization

The functional complementarity of the vestibulo-ocular reflex (VOR) and optokinetic reflex (OKR) allows for optimal combined gaze stabilization responses (CGR) in light. While sensory substitution has been reported following complete vestibular loss, the capacity of the central vestibular system to compensate for partial peripheral vestibular loss remains to be determined. Here, we first demonstrate the efficacy of a 6-week subchronic ototoxic protocol in inducing transient and partial vestibular loss which equally affects the canal- and otolith-dependent VORs. Immunostaining of hair cells in the vestibular sensory epithelia revealed that organ-specific alteration of type I, but not type II, hair cells correlates with functional impairments. The decrease in VOR performance is paralleled with an increase in the gain of the OKR occurring in a specific range of frequencies where VOR normally dominates gaze stabilization, compatible with a sensory substitution process. Comparison of unimodal OKR or VOR versus bimodal CGR revealed that visuo-vestibular interactions remain reduced despite a significant recovery in the VOR. Modeling and sweep-based analysis revealed that the differential capacity to optimally combine OKR and VOR correlates with the reproducibility of the VOR responses. Overall, these results shed light on the multisensory reweighting occurring in pathologies with fluctuating peripheral vestibular malfunction.

neuroscience↗

bioRxiv2021

Conservation of locomotion-induced oculomotor activity through evolution in higher tetrapods

Efference copies are neural replicas of motor outputs used to anticipate the sensory consequences of a self-generated motor action or to coordinate neural networks involved in distinct motor behaviors1. An established example of this motor-to-motor coupling is the efference copy of the propulsive motor command that supplements classical visuo-vestibular reflexes to ensure gaze stabilization during amphibian larval locomotion2. Such feedforward replica from spinal pattern-generating circuits produces a spino-extraocular motor coupled activity that evokes eye movements, spatio-temporally coordinated to tail undulation independently of any sensory signal3,4. Exploiting the evolutionary-development characteristic of the frog1, studies in metamorphing Xenopus demonstrated the persistence of this spino-extraocular motor command in adults, and its developmental adaptation to tetrapodal locomotion5,6. Here, we demonstrate for the first time the existence of a comparable locomotor-to-ocular motor coupling in the mouse. In neonates, ex vivo nerve recordings from brainstem-spinal cord preparation reveals a spino-extraocular motor coupled activity similar to the one described in Xenopus. In adult mice, trans-synaptic rabies injection in lateral rectus eye muscle labels cervical spinal cord neurons projecting directly to abducens motor neurons. Finally, treadmill-elicited locomotion in decerebrated preparations7 evokes rhythmic eye movements in synchrony with the limb gait pattern. Overall, our data are evidence for the conservation of locomotor-induced eye movements in higher tetrapods. Thus, in mammals as in amphibians, during locomotion CPG-efference copy feedforward signals might interact with sensory feedback to ensure efficient gaze control. HighlightsO_LISpino-extraocular motor coupling is evidenced from newborn mice ex vivo preparations C_LIO_LIAdult decerebrated mice exhibit conjugated rhythmic eye movements during treadmill locomotion C_LIO_LILocomotor-induced oculomotor activity occurs in absence of visuo-vestibular inputs C_LIO_LIConserved CPG-based efference copy signal in vertebrates with common features. C_LI eTOC blurbWe report a functional coupling between spinal locomotor and oculomotor networks in the mouse, similar to the one previously described in Amphibians. This is the first evidence for the direct contribution of locomotor networks to gaze control in mammals, suggesting a conservation of the spino-extraocular coupling in higher tetrapods during sustained locomotion.

neuroscience↗

bioRxiv2020

Does gravity shape internal representations of space for human 3D perception?

Human 3D perception of visual objects is flawed by distortions, which are influenced by non-visual factors, such as gravitational vestibular signals. Whether gravity acts specifically on the visual system or at a higher, modality-independent, level of information processing remains unknown. To test these modality-specific vs modality-independent hypotheses, we performed experiments comparing visual versus haptic 3D shape perception in normo-gravity and microgravity. The results obtained for upright and supine posture in 1g show that visual and haptic perceptual anisotropies are systematically in opposing ego-centered, but not gravity-centered, directions suggesting they share a common origin. On the other hand, microgravity significantly modulates both visual and haptic perceptual distortion in the same direction. Overall, our results show a clear link between the visual and haptic perceptual distortions and demonstrate a role of gravity-related signals on a modality-independent internal representation of 3D space used to interpret incoming sensory inputs.

neuroscience↗