Background: While strong vestibular input to the fastigial nucleus has been demonstrated, little is known on how this is integrated in the oculomotor region of the caudal area of fastigial nucleus. In this study, single units in the caudal region of the fastigial nucleus were recorded in the rat, while applying sinusoidal galvanic stimuli to the labyrinths.
Material/methods: The left and right labyrinths were polarized with either monaural or binaural sinusoidal stimuli (0.5 hertz), with stimulus phase shifts between right and left in 90 degrees steps (90 degrees, 180 degrees, 270 degrees, 360 degrees). The study describes the interaction and integration between the information of both labyrinths in the caudal fastigial nucleus.
Results: In 23 neurons, the relationship between input (galvanic stimuli to the labyrinths) and output (neuronal discharge) was analyzed for a series of stimuli (102 recordings in total). During monaural stimulation, phase shifts greater than 45 degrees were observed in 14 of 23 neurons (60.9%) during stimulation to the left and right labyrinths. To explain this phenomenon and the previously observed tuning characteristics in the fastigial nucleus, the neuronal responses were regarded as vectors. Thus, the observed response for binaural stimulation appeared to correspond to a vector addition of the left and right vestibular afferents. Of the 23 neurons, 14 neurons (60.9%) indicated a difference between predicted and measured values of less than 14.1 degrees.
Conclusions: The findings support a working model based on vector addition of vestibular afferents in the caudal fastigial nucleus.
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Cell Rep
December 2024
Centre for Neuroscience, Indian Institute of Science, Bengaluru, Karnataka 560012, India. Electronic address:
Skilled forelimb control is essential for daily living, yet our understanding of its neural mechanisms, although extensive, remains incomplete. Here, we present evidence that the superior colliculus (SC), a major midbrain structure, is necessary for accurate forelimb reaching in mice. We found that neurons in the lateral SC are active during goal-directed reaching, and by employing chemogenetic and phase-specific optogenetic silencing of these neurons, we show that the SC causally facilitates reach accuracy.
View Article and Find Full Text PDFEur J Neurol
January 2025
Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, South Korea.
Background And Purpose: The dorsolateral portion of the caudal pons contains the vestibular nucleus (VN) and inferior cerebellar peduncle (ICP) that play important roles in conveying and processing vestibular and ocular motor signals. This study aimed to characterize ocular motor abnormalities along with their anatomical correlations in dorsolateral pons (DLP) lesions.
Methods: We analyzed clinical features, and results of neuro-otological evaluations and neuroimaging of 18 patients with unilateral DLP lesions (17 with DLP infarction and 1 with cavernous malformation) from among 506 patients with pontine infarction in a stroke registry.
Clin Toxicol (Phila)
December 2024
Department of Neuroradiology, Unidade Local de Saúde de Santa Maria, Lisboa, Portugal.
Introduction: Vigabatrin, an anticonvulsant drug used for refractory epilepsy and as first-line treatment for infantile epileptic spasms syndrome, can rarely cause brain abnormalities detectable on magnetic resonance imaging. These complications, potentially related to dose, young age, and concomitant high doses of adrenocorticotropic hormone and/or prednisolone, can lead to neurological symptoms. Upon withdrawal or dose reduction, symptoms and imaging changes tend to resolve.
View Article and Find Full Text PDFElife
December 2024
Department of Human Anatomy and Cell Science, The Children's Hospital Research Institute of Manitoba (CHRIM), Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada.
Cerebellar nuclei (CN) neurons serve as the primary output of the cerebellum and originate from the cerebellar primordium at early stages of cerebellar development. These neurons are diverse, integrating information from the cerebellar cortex and relaying it to various brain regions. Employing various methodologies, we have characterized a specific subset of CN neurons that do not originate from the rhombic lip or ventricular zone of the cerebellar primordium.
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