New insights into vestibular-saccade interaction based on covert corrective saccades in patients with unilateral vestibular deficits
| Autor: | Georgios Mantokoudis, Stefano Ramat, Marco Manfrin, Maurizio Versino, David S. Zee, Silvia Colnaghi, Paolo Colagiorgio, Ewa Zamaro, Silvia Quaglieri |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Adult
Male 0301 basic medicine medicine.medical_specialty genetic structures Physiology Head (linguistics) Models Neurological 610 Medicine & health Audiology 03 medical and health sciences 0302 clinical medicine Saccades medicine Humans In patient Aged Feedback Physiological Vestibular system Communication VOR covert saccades gaze feedback loop mathematical model vestibular neuritis business.industry General Neuroscience Reflex Vestibulo-Ocular Middle Aged 030104 developmental biology Vestibular Diseases Covert Saccade Vestibular neuritis Female business Psychology 030217 neurology & neurosurgery Research Article |
| Zdroj: | Colagiorgio, Paolo; Versino, Maurizio; Colnaghi, Silvia; Quaglieri, Silvia; Manfrin, Marco; Zamaro, Ewa; Mantokoudis, Georgios; Zee, David S; Ramat, Stefano (2017). New insights into vestibular-saccade interaction based on covert corrective saccades in patients with unilateral vestibular deficits. Journal of neurophysiology, 117(6), pp. 2324-2338. American Physiological Society 10.1152/jn.00864.2016 |
| DOI: | 10.7892/boris.110929 |
| Popis: | In response to passive high-acceleration head impulses, patients with low vestibulo-ocular reflex (VOR) gains often produce covert (executed while the head is still moving) corrective saccades in the direction of deficient slow phases. Here we examined 23 patients using passive, and 9 also active, head impulses with acute (< 10 days from onset) unilateral vestibular neuritis and low VOR gains. We found that when corrective saccades are larger than 10°, the slow-phase component of the VOR is inhibited, even though inhibition increases further the time to reacquire the fixation target. We also found that 1) saccades are faster and more accurate if the residual VOR gain is higher, 2) saccades also compensate for the head displacement that occurs during the saccade, and 3) the amplitude-peak velocity relationship of the larger corrective saccades deviates from that of head-fixed saccades of the same size. We propose a mathematical model to account for these findings hypothesizing that covert saccades are driven by a desired gaze position signal based on a prediction of head displacement using vestibular and extravestibular signals, covert saccades are controlled by a gaze feedback loop, and the VOR command is modulated according to predicted saccade amplitude. A central and novel feature of the model is that the brain develops two separate estimates of head rotation, one for generating saccades while the head is moving and the other for generating slow phases. Furthermore, while the model was developed for gaze-stabilizing behavior during passively induced head impulses, it also simulates both active gaze-stabilizing and active gaze-shifting eye movements.NEW & NOTEWORTHY During active or passive head impulses while fixating stationary targets, low vestibulo-ocular gain subjects produce corrective saccades when the head is still moving. The mechanisms driving these covert saccades are poorly understood. We propose a mathematical model showing that the brain develops two separate estimates of head rotation: a lower level one, presumably in the vestibular nuclei, used to generate the slow-phase component of the response, and a higher level one, within a gaze feedback loop, used to drive corrective saccades. |
| Databáze: | OpenAIRE |
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