Purpose: Remyelination therapies are advancing for multiple sclerosis, focusing on visual pathways and using visual evoked potentials (VEPs) for de/remyelination processes. While the cuprizone (CZ) model and VEPs are core tools in preclinical trials, many overlook the posterior visual pathway. This study aimed to assess functional and structural changes across the murine visual pathway during de/remyelination.
Methods: One group of C57BL/6 mice underwent a CZ diet for 6 weeks to simulate demyelination, with a subset returning to a regular diet to induce remyelination. An additional group was fed a protracted CZ diet for 12 weeks to maintain chronic demyelination. Visual function was evaluated using electrophysiological recordings, including scotopic threshold responses (STRs) and electroretinograms (ERGs), with VEPs serving as a key biomarker for overall pathway health. Tissues from eyes, brains, and optic nerves (ONs) were collected at different time points for structural analysis.
Results: Our results demonstrated significant effects on VEPs, including increased N1 latencies and reduced amplitudes in the CZ mouse model. However, retinal function remained unaffected, as evidenced by unchanged STRs, ERGs, and retinal ganglion cell counts. Analysis of ONs revealed morphological changes, characterized by a significantly decreased axon diameter in the core region compared to the subpial region. Additionally, there was a significant increase in the g-ratio of the core region at 12 weeks CZ compared to controls. Immunofluorescence further demonstrated a decrease in myelin basic protein levels at 6 and 12 weeks in CZ animals. Interestingly, the dorsal lateral geniculate nucleus and primary visual cortex (V1) exhibited similar myelin changes, correlating with VEP latency alterations.
Conclusions: These data reveal that interpreting VEP latency solely as a marker for ON demyelination is incomplete. Previous preclinical studies have overlooked the posterior visual pathways, necessitating a broader interpretation of VEP latency to cover the entire visual pathway.
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http://dx.doi.org/10.1167/iovs.65.13.50 | DOI Listing |
Front Syst Neurosci
December 2024
Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.
Evoked potentials can be used as an intraoperative monitoring measure in neurological surgery. Auditory evoked potentials (AEPs), or specifically brainstem auditory evoked responses (BAERs), are known for being minimally affected by anesthetics, while visually evoked potentials (VEPs) are presumed to be unreliable and easily affected by anesthetics. While many anesthesia trials or intraoperative recordings have provided evidence in support of these hypotheses, the comparisons were always made between AEPs and VEPs recorded sequentially, rather than recorded at the same time.
View Article and Find Full Text PDFJ Clin Med
November 2024
Cochlear Implant Center, Department of Otorhinolaryngology, Head and Neck Surgery, Catholic Hospital Bochum, Ruhr University Bochum, Bleichstr. 15, 44787 Bochum, Germany.
Sensory loss may lead to intra- and cross-modal cortical reorganization. Previous research showed a significant correlation between the cross-modal contribution of the right auditory cortex to visual evoked potentials (VEP) and speech perception in cochlear implant (CI) users with prelingual hearing loss (HL), but not in those with postlingual HL. The present study aimed to explore the cortical reorganization induced by postlingual HL, particularly in the right temporal region, and how it correlates with speech perception outcome with a CI.
View Article and Find Full Text PDFJ Fr Ophtalmol
December 2024
Department of Ophtalmology, Habib Bourguiba University Hospital, Faculty of Medicine of Sfax, University of Sfax, Sfax, Tunisia.
Purpose: To study retinal layers on OCT in patients with multiple sclerosis (MS) and look for correlations with clinical and electrophysiological characteristics.
Methods: We conducted a cross-sectional study including MS patients aged between 18 and 60 years and a reference group of healthy, age- and gender-matched, control participants. A neurological examination with assessment of disability by the Expanded Disability Status Scale (EDSS), an ophthalmological examination, a spectral-domain OCT, and visual evoked potentials (VEP) were performed.
Mult Scler Relat Disord
November 2024
Biogen, Cambridge, MA, USA. Electronic address:
Background: The randomized, phase 2 RENEW trial (NCT01721161) evaluated efficacy/safety of opicinumab (anti-LINGO-1) versus placebo in patients with first-episode unilateral acute optic neuritis (AON). Although no significant differences in the latency recovery of visual evoked potential (VEP) were observed between opicinumab and placebo groups in the intention to treat (ITT) population, the prespecified per-protocol (PP) population showed better recovery with opicinumab than with placebo. RENEWED (NCT02657915) was a one-visit, follow-up study 2 years after the last RENEW study visit (Week 32) designed to assess the long-term electrophysiological and clinical outcomes for participants previously enrolled and having received study treatment in RENEW.
View Article and Find Full Text PDFNeurosci Insights
November 2024
Department of Vision Therapy, Southern College of Optometry, Memphis, TN, USA.
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