Search Our Scientific Publications & Authors

J Neuroophthalmol 2020 06;40(2):226-233

Departments of Neurology and Biomedical Engineering (P.G., A.G.S.), Case Western Reserve University, Cleveland, Ohio; Neurological Institute (P.G., A.G.S.), University Hospitals Cleveland Medical Center, Cleveland, Ohio; and Daroff-Dell'Osso Ocular Motor Laboratory (P.G., A.G.S.), Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio.

The mechanism for stable gaze-holding requires a neural integrator that converts pulse of neural discharge to steady firing rate. The integrator is feedback-dependent, impaired feedback manifests as either "unstable" integration when it is too much or "leaky" when it is too little. The "unstable" integrator is known to cause sinusoidal oscillations of the eyes called pendular nystagmus, whereas the "leaky" integrator causes jerky eye oscillations called gaze-evoked nystagmus. Read More

J Vestib Res 2019 ;29(5):241-251

Neuroscience Laboratories, NASA Johnson Space Center, Houston, USA.

Background: The vestibulo-ocular reflex (VOR) is a basic function of the vestibular system that stabilizes gaze during head movement. Investigations on how spaceflight affects VOR gain and phase are few, and the magnitude of observed changes varies considerably and depends on the protocols used.

Objective: We investigated whether the gain and phase of the VOR in darkness and the visually assisted VOR were affected during and after spaceflight. Read More

Genes (Basel) 2018 Dec 4;9(12). Epub 2018 Dec 4.

Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Palo Alto, CA 94305, USA.

Joubert syndrome is a group of rare disorders that stem from defects in a sensory organelle, the primary cilia. Affected patients often present with disorders involving multiple organ systems, including the brain, eyes, and kidneys. Common symptoms include breathing abnormalities, mental developmental delays, loss of voluntary muscle coordination, and abnormal eye movements, with a diagnostic "molar tooth" sign observed by magnetic resonance imaging (MRI) of the midbrain. Read More

Neuroscience 2018 11 5;392:281-328. Epub 2018 Sep 5.

Department of Systems Neurophysiology, Tokyo Medical and Dental University, Graduate School of Medicine, Tokyo, Japan.

Sensory signals for eye movements (visual and vestibular) are initially coded in different frames of reference but finally translated into common coordinates, and share the same final common pathway, namely the same population of extraocular motoneurons. From clinical studies in humans and lesion studies in animals, it is generally accepted that voluntary saccadic eye movements are organized in horizontal and vertical Cartesian coordinates. However, this issue is not settled yet, because neural circuits for vertical saccades remain unidentified. Read More

Sleep Med 2018 02 25;42:97-102. Epub 2017 Oct 25.

Department of Neurology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India. Electronic address:

Objectives: Spinocerebellar ataxias are progressive neurodegenerative disorders characterized by progressive cerebellar features with additional neuro-axis involvement. Oculomotor abnormality is one of the most frequent manifestations. This study was done to assess the polysomnographic abnormalities in patients with Spinocerebellar ataxia (SCA1, SCA2 and SCA3) and also to evaluate whether oculomotor abnormalities interfere with sleep stage R scoring. Read More