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Ahn SY, Jung EH, Ahn H, Lee JS, Bak JH, Kim ED, Song JH, Shin HS, Jamiyansharav M, Seo KY. Automatic measurement of mouse visual acuity based on optomotor response: SKY optomotry. Lab Anim 2023; 57:412-423. [PMID: 36708198 DOI: 10.1177/00236772221148576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In the field of visual science study using rodents, several assessment methods have been developed for measuring visual function. However, methods such as electroretinograms tests, visual evoked potentials tests and maze tests have limitations in that they measure function of only a specific type of cells, are difficult to quantify or require sufficient training time. The method which uses an optokinetic reflex and optomotor response, a compensatory eye and head movement in response to changes in the visual scene, became the most widely used method. However, this method requires highly trained experimenters and is time consuming. We showed that measured visual acuity values are significantly different between beginner and expert. Here we suggest an automated optometry program, 'SKY optomotry', which automatically tracks rodents' optomotor response to overcome subjectivity and the lengthy scoring procedure of the existing method. To evaluate the performance of SKY optomotry using 8-12-week-old C57BL/6 mice we compared the binomial decision of SKY optomotry with a skilled expert, and the area under the curve of SKY optomotry was 0.845. Comparing the final visual acuity, the intraclass correlation coefficient value between SKY optomotry and an expert was 0.860 (95% confidence interval (CI) 0.709-0.928), whereas that between an expert and a beginner was 0.642 (95% CI 0.292-0.811). SKY optomotry showed an excellent level of performance with good inter-rater agreements based on the visual acuity measured by an expert. With the use of our application, researchers will be able to test an experimental animal's eyesight more accurately while saving time on specialized training.
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Affiliation(s)
- So Yeon Ahn
- Department of Medicine, Yonsei University College of Medicine, Republic of Korea
| | - Eun Hye Jung
- Department of Medicine, Yonsei University College of Medicine, Republic of Korea
| | - Hyunmin Ahn
- Department of Medicine, Yonsei University College of Medicine, Republic of Korea
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Republic of Korea
| | - Jihei Sara Lee
- Department of Medicine, Yonsei University College of Medicine, Republic of Korea
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Republic of Korea
| | - Jeong Hyeon Bak
- Department of Mechanical Engineering, Hanyang University, Republic of Korea
| | - Eun-do Kim
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA
| | - Ja-Hyun Song
- Korea Mouse Sensory Phenotyping Center (KMSPC), Yonsei University College of Medicine, Republic of Korea
| | - Hae-Sol Shin
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Republic of Korea
- Korea Mouse Sensory Phenotyping Center (KMSPC), Yonsei University College of Medicine, Republic of Korea
| | | | - Kyoung Yul Seo
- Department of Medicine, Yonsei University College of Medicine, Republic of Korea
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Republic of Korea
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Marenna S, Rossi E, Huang SC, Castoldi V, Comi G, Leocani L. Visual evoked potentials waveform analysis to measure intracortical damage in a preclinical model of multiple sclerosis. Front Cell Neurosci 2023; 17:1186110. [PMID: 37323584 PMCID: PMC10264580 DOI: 10.3389/fncel.2023.1186110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 05/08/2023] [Indexed: 06/17/2023] Open
Abstract
Introduction Visual evoked potentials (VEPs) are a non-invasive technique routinely used in clinical and preclinical practice. Discussion about inclusion of VEPs in McDonald criteria, used for Multiple Sclerosis (MS) diagnosis, increased the importance of VEP in MS preclinical models. While the interpretation of the N1 peak is recognized, less is known about the first and second positive VEP peaks, P1 and P2, and the implicit time of the different segments. Our hypothesis is that P2 latency delay describes intracortical neurophysiological dysfunction from the visual cortex to the other cortical areas. Methods In this work, we analyzed VEP traces that were included in our two recently published papers on Experimental Autoimmune Encephalomyelitis (EAE) mouse model. Compared with these previous publications other VEP peaks, P1 and P2, and the implicit time of components P1-N1, N1-P2 and P1-P2, were analyzed in blind. Results Latencies of P2, P1-P2, P1-N1 and N1-P2 were increased in all EAE mice, including group without N1 latency change delay at early time points. In particular, at 7 dpi the P2 latency delay change was significantly higher compared with N1 latency change delay. Moreover, new analysis of these VEP components under the influence of neurostimulation revealed a decrease in P2 delay in stimulated animals. Discussion P2 latency delay, P1-P2, P1-N1, and N1-P2 latency changes which reflect intracortical dysfunction, were consistently detected across all EAE groups before N1 change. Results underline the importance of analyzing all VEP components for a complete overview of the neurophysiological visual pathway dysfunction and treatment efficacy.
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Affiliation(s)
- Silvia Marenna
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE)–IRCCS-Scientific Institute San Raffaele, Milan, Italy
| | - Elena Rossi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE)–IRCCS-Scientific Institute San Raffaele, Milan, Italy
- Faculty of Medicine, Università Vita-Salute San Raffaele, Milan, Italy
| | - Su-Chun Huang
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE)–IRCCS-Scientific Institute San Raffaele, Milan, Italy
| | - Valerio Castoldi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE)–IRCCS-Scientific Institute San Raffaele, Milan, Italy
| | - Giancarlo Comi
- Faculty of Medicine, Università Vita-Salute San Raffaele, Milan, Italy
- Department of Neurorehabilitation Sciences, Casa di Cura Igea, Milan, Italy
| | - Letizia Leocani
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE)–IRCCS-Scientific Institute San Raffaele, Milan, Italy
- Faculty of Medicine, Università Vita-Salute San Raffaele, Milan, Italy
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Rossi G, Ordazzo G, Vanni NN, Castoldi V, Iannielli A, Di Silvestre D, Bellini E, Bernardo L, Giannelli SG, Luoni M, Muggeo S, Leocani L, Mauri P, Broccoli V. MCT1-dependent energetic failure and neuroinflammation underlie optic nerve degeneration in Wolfram syndrome mice. eLife 2023; 12:81779. [PMID: 36645345 PMCID: PMC9891717 DOI: 10.7554/elife.81779] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 01/13/2023] [Indexed: 01/17/2023] Open
Abstract
Wolfram syndrome 1 (WS1) is a rare genetic disorder caused by mutations in the WFS1 gene leading to a wide spectrum of clinical dysfunctions, among which blindness, diabetes, and neurological deficits are the most prominent. WFS1 encodes for the endoplasmic reticulum (ER) resident transmembrane protein wolframin with multiple functions in ER processes. However, the WFS1-dependent etiopathology in retinal cells is unknown. Herein, we showed that Wfs1 mutant mice developed early retinal electrophysiological impairments followed by marked visual loss. Interestingly, axons and myelin disruption in the optic nerve preceded the degeneration of the retinal ganglion cell bodies in the retina. Transcriptomics at pre-degenerative stage revealed the STAT3-dependent activation of proinflammatory glial markers with reduction of the homeostatic and pro-survival factors glutamine synthetase and BDNF. Furthermore, label-free comparative proteomics identified a significant reduction of the monocarboxylate transport isoform 1 (MCT1) and its partner basigin that are highly enriched on retinal glia and myelin-forming oligodendrocytes in optic nerve together with wolframin. Loss of MCT1 caused a failure in lactate transfer from glial to neuronal cell bodies and axons leading to a chronic hypometabolic state. Thus, this bioenergetic impairment is occurring concurrently both within the axonal regions and cell bodies of the retinal ganglion cells, selectively endangering their survival while impacting less on other retinal cells. This metabolic dysfunction occurs months before the frank RGC degeneration suggesting an extended time-window for intervening with new therapeutic strategies focused on boosting retinal and optic nerve bioenergetics in WS1.
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Affiliation(s)
- Greta Rossi
- Division of Neuroscience, San Raffaele Scientific InstituteMilanoItaly
| | - Gabriele Ordazzo
- Division of Neuroscience, San Raffaele Scientific InstituteMilanoItaly
| | - Niccolò N Vanni
- Division of Neuroscience, San Raffaele Scientific InstituteMilanoItaly
| | - Valerio Castoldi
- Division of Neuroscience, San Raffaele Scientific InstituteMilanoItaly
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), San Raffaele Scientific InstituteMilanItaly
| | - Angelo Iannielli
- Division of Neuroscience, San Raffaele Scientific InstituteMilanoItaly
- National Research Council of Italy, Institute of NeuroscienceMilanoItaly
| | - Dario Di Silvestre
- National Research Council of Italy, Institute of Technologies in BiomedicineMilanItaly
| | - Edoardo Bellini
- Division of Neuroscience, San Raffaele Scientific InstituteMilanoItaly
| | - Letizia Bernardo
- National Research Council of Italy, Institute of Technologies in BiomedicineMilanItaly
| | | | - Mirko Luoni
- Division of Neuroscience, San Raffaele Scientific InstituteMilanoItaly
- National Research Council of Italy, Institute of NeuroscienceMilanoItaly
| | - Sharon Muggeo
- Division of Neuroscience, San Raffaele Scientific InstituteMilanoItaly
| | - Letizia Leocani
- Division of Neuroscience, San Raffaele Scientific InstituteMilanoItaly
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), San Raffaele Scientific InstituteMilanItaly
| | - PierLuigi Mauri
- National Research Council of Italy, Institute of Technologies in BiomedicineMilanItaly
| | - Vania Broccoli
- Division of Neuroscience, San Raffaele Scientific InstituteMilanoItaly
- National Research Council of Italy, Institute of NeuroscienceMilanoItaly
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Mansouri V. X-Linked Retinitis Pigmentosa Gene Therapy: Preclinical Aspects. Ophthalmol Ther 2022; 12:7-34. [PMID: 36346573 PMCID: PMC9641696 DOI: 10.1007/s40123-022-00602-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022] Open
Abstract
The most common inherited eye disease is retinitis pigmentosa (RP). X-linked RP (XLRP) is one of the most severe types of RP, with a considerable disease burden. Patients with XLRP experience a decrease in their vision and become blind in their 4th decade of life, causing much morbidity after starting a rather normal life. Treatment of XLRP remains challenging, and current treatments are not effective enough in restoring vision. Gene therapy of XLRP, capable of restoring the functional RPGR gene, showed promising results in preclinical studies and clinical trials; however, to date, no approved product has entered the market. The development of a gene therapy product needs through preliminary assessment of the drug in animal models before administration to humans. In this article, we reviewed the genetic pathology of XLRP, along with the preclinical aspects of the XLRP gene therapy, animal models, associated assessments, and future challenges and directions.
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Affiliation(s)
- Vahid Mansouri
- Gene Therapy Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.
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Marenna S, Huang SC, Rossi E, Castoldi V, Comi G, Leocani L. Transcranial direct current stimulation as a preventive treatment in multiple sclerosis? Preclinical evidence. Exp Neurol 2022; 357:114201. [PMID: 35963325 DOI: 10.1016/j.expneurol.2022.114201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 07/28/2022] [Accepted: 08/08/2022] [Indexed: 11/26/2022]
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system, presenting with optic neuritis in about 20-30% of cases. Optic nerve demyelination, associated with delay of visual evoked potentials (VEPs), is also observed prior to motor signs in the preclinical MS model Experimental Autoimmune Encephalomyelitis (EAE). Transcranial direct current stimulation (tDCS), inducing polarity-dependent changes in neuronal excitability, is widely used to promote neuroplasticity in several neurological disorders. However, its potential effects on inflammation and demyelination are largely unknown. We tested the effectiveness of a preventive, 5-day tDCS treatment started 3 days post-immunization, in reducing the severity of VEP delays observed in early EAE. In mice undergoing cathodal tDCS (n = 6/26 eyes) VEPs were significantly less delayed compared with eyes from EAE-Sham (n = 24/32 eyes) and EAE-Anodal (n = 22/32 eyes). Optic nerve immunohistochemistry revealed a significantly lower cell density of microglia/macrophages, and less axonal loss in EAE-Cathodal vs EAE-Sham and EAE-Anodal, while the percent demyelination with Luxol-fast blue staining was comparable among EAE groups. Considering the latter result, immunofluorescence paranodal staining was performed, revealing a significantly higher number of complete paranode domains in EAE-Cathodal, closer to healthy mice, compared with EAE-Sham and EAE-Anodal groups. These results were reflected by the negative correlation between the number of complete paranode domains and VEP latency increase with respect to pre-immunization. Finally, cathodal tDCS was associated with a lower number, closer to healthy, of single paranodes in contrast to EAE-Sham. The effects of cathodal stimulation in preventing VEPs delays and optic nerve myelin damage were already observed in the pre-motor onset EAE stage, and were associated with a lower density of inflammatory cells. These findings suggest that tDCS may exert an anti-inflammatory effect with potential therapeutic application to be further explored in autoimmune demyelinating diseases.
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Affiliation(s)
- Silvia Marenna
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE) - IRCCS-San Raffaele Hospital, via Olgettina 60, 20132 Milan, Italy.
| | - Su-Chun Huang
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE) - IRCCS-San Raffaele Hospital, via Olgettina 60, 20132 Milan, Italy.
| | - Elena Rossi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE) - IRCCS-San Raffaele Hospital, via Olgettina 60, 20132 Milan, Italy.
| | - Valerio Castoldi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE) - IRCCS-San Raffaele Hospital, via Olgettina 60, 20132 Milan, Italy.
| | - Giancarlo Comi
- Università Vita-Salute, San Raffaele Hospital, via Olgettina 60, 20132 Milan, Italy; Casa di Cura del Policlinico, Milan, Italy.
| | - Letizia Leocani
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE) - IRCCS-San Raffaele Hospital, via Olgettina 60, 20132 Milan, Italy; Università Vita-Salute, San Raffaele Hospital, via Olgettina 60, 20132 Milan, Italy.
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Marenna S, Huang SC, Dalla Costa G, d’Isa R, Castoldi V, Rossi E, Comi G, Leocani L. Visual Evoked Potentials to Monitor Myelin Cuprizone-Induced Functional Changes. Front Neurosci 2022; 16:820155. [PMID: 35495042 PMCID: PMC9051229 DOI: 10.3389/fnins.2022.820155] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/07/2022] [Indexed: 11/17/2022] Open
Abstract
The visual system is one of the most accessible routes to study the central nervous system under pathological conditions, such as in multiple sclerosis (MS). Non-invasive visual evoked potential (VEP) and optical coherence tomography (OCT) were used to assess visual function and neuroretinal thickness in C57BL/6 taking 0.2% cuprizone for 7 weeks and at 5, 8, 12, and 15 days after returning to a normal diet. VEPs were significantly delayed starting from 4 weeks on cuprizone, with progressive recovery off cuprizone, becoming significant at day 8, complete at day 15. In contrast, OCT and neurofilament staining showed no significant axonal thinning. Optic nerve histology indicated that whilst there was significant myelin loss at 7 weeks on the cuprizone diet compared with healthy mice, at 15 days off cuprizone diet demyelination was significantly less severe. The number of Iba 1+ cells was found increased in cuprizone mice at 7 weeks on and 15 days off cuprizone. The combined use of VEPs and OCT allowed us to characterize non-invasively, in vivo, the functional and structural changes associated with demyelination and remyelination in a preclinical model of MS. This approach contributes to the non-invasive study of possible effective treatments to promote remyelination in demyelinating pathologies.
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Affiliation(s)
- Silvia Marenna
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), IRCCS-Scientific Institute San Raffaele, Milan, Italy
| | - Su-Chun Huang
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), IRCCS-Scientific Institute San Raffaele, Milan, Italy
| | - Gloria Dalla Costa
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), IRCCS-Scientific Institute San Raffaele, Milan, Italy
- Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy
| | - Raffaele d’Isa
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), IRCCS-Scientific Institute San Raffaele, Milan, Italy
| | - Valerio Castoldi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), IRCCS-Scientific Institute San Raffaele, Milan, Italy
| | - Elena Rossi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), IRCCS-Scientific Institute San Raffaele, Milan, Italy
| | - Giancarlo Comi
- Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Casa di Cura Privata del Policlinico, Milan, Italy
| | - Letizia Leocani
- Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), IRCCS-Scientific Institute San Raffaele, Milan, Italy
- Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- *Correspondence: Letizia Leocani,
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Liu S, Xiang K, Lei Q, Qiu S, Xiang M, Jin K. An optimized procedure to record visual evoked potential in mice. Exp Eye Res 2022; 218:109011. [PMID: 35245512 DOI: 10.1016/j.exer.2022.109011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 02/09/2022] [Accepted: 02/22/2022] [Indexed: 11/04/2022]
Abstract
Visual evoked potential (VEP) is commonly used to evaluate visual acuity in both clinical and basic studies. Subdermal needle electrodes or skull pre-implanted screw electrodes are usually used to record VEP in rodents. However, the VEP amplitudes recorded by the former are small while the latter may damage the brain. In this study, we established a new invasive procedure for VEP recording, and made a series of comparisons of VEP parameters recorded from different electrode locations, different times of day (day and night) and bilateral eyes, to evaluate the influence of these factors on VEP in mice. Our data reveal that our invasive method is reliable and can record VEP with good waveforms and large amplitudes. The comparison data show that VEP is greatly influenced by active electrode locations and difference between day and night. In C57 or CD1 ONC (optic nerve crush) models and Brn3bAP/AP mice, which are featured by loss of retinal ganglion cells (RGCs), amplitudes of VEP N1 and P1 waves are drastically reduced. The newly established VEP procedure is very reliable and stable, and is particularly useful for detecting losses of RGC quantities, functions or connections to the brain. Our analyses of various recording conditions also provide useful references for future studies.
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Affiliation(s)
- Shuting Liu
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong Province, 510060, China
| | - Kangjian Xiang
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong Province, 510060, China
| | - Qiannan Lei
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong Province, 510060, China
| | - Suo Qiu
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong Province, 510060, China
| | - Mengqing Xiang
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong Province, 510060, China; Guangzhou Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong Province, 510080, China.
| | - Kangxin Jin
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong Province, 510060, China.
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Castoldi V, Rossi E, Marenna S, Comi G, Leocani L. Improving reproducibility of motor evoked potentials in mice. J Neurosci Methods 2022; 367:109444. [PMID: 34921842 DOI: 10.1016/j.jneumeth.2021.109444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/13/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND In preclinical research involving murine models of neurological diseases, Motor Evoked Potentials (MEPs) can detect pathological alterations in nerve conduction throughout the cortico-spinal tract. In mice, MEPs elicited by electrical stimulation of the motor cortex can be performed with epicranial or subdermal electrodes such as implanted screws or removable needles, which are associated with invasive surgery and variability in placement of the stimulating electrodes, respectively. METHODS We compared MEPs induced by epicranial or subcutaneous stimulation with a non-invasive surface cup electrode over five recording sessions, in healthy C57BL/6 mice. Additionally, using surface stimulation, we examined the recordings obtained with intramuscular needles or surface electrodes to understand if MEP reproducibility could be improved. RESULTS Resting motor threshold (RMT), MEP latency and amplitude were comparable among the different stimulation methods. Epicranial, subcutaneous and surface stimulation techniques presented good repeatability over time, with surface stimulation showing a significantly reduced inter-session variability. Compared with intramuscular needles, MEPs recorded with surface electrode showed reduced peak-to-peak amplitude at all timepoints. RMT and MEP latency were comparable with both recording methods. On the other hand, amplitudes recorded with the surface electrode presented a significantly lower inter-session variance, resulting in improved repeatability. CONCLUSION Overall, there is evidence for highly reproducible results using different stimulating methods, with indication for reduced inter-session variability for surface stimulation. Moreover, MEP recording with surface electrode provided a decrease in amplitude variability over time, indicating improved measurement stability when considering amplitude as functional outcome in longitudinal studies.
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Affiliation(s)
- Valerio Castoldi
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Elena Rossi
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Silvia Marenna
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Giancarlo Comi
- Vita-Salute San Raffaele University, via Olgettina 58, 20132 Milan, Italy; Casa di Cura del Policlinico, via Giuseppe Dezza, 48, 20144 Milan, Italy
| | - Letizia Leocani
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy; Vita-Salute San Raffaele University, via Olgettina 58, 20132 Milan, Italy.
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Castoldi V, Marenna S, Huang SC, d'Isa R, Chaabane L, Comi G, Leocani L. Dose-dependent effect of myelin oligodendrocyte glycoprotein on visual function and optic nerve damage in experimental autoimmune encephalomyelitis. J Neurosci Res 2022; 100:855-868. [PMID: 35043454 DOI: 10.1002/jnr.25007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 11/29/2021] [Accepted: 12/21/2021] [Indexed: 11/08/2022]
Abstract
Female Dark Agouti rats were immunized with increasing doses of myelin oligodendrocyte glycoprotein (MOG) to develop experimental autoimmune encephalomyelitis (EAE), a preclinical model of multiple sclerosis. Typical EAE motor impairments were assessed daily and noninvasive visual evoked potentials (VEPs) were recorded at baseline and 5 weeks after immunization, with final histopathology of optic nerves (ONs). Immunized rats exhibited a relapsing-remitting clinical course. Both VEP and histological abnormalities were detected in a MOG dose-dependent gradient. Increasing MOG dosage augmented visual function impairment in EAE, which could be monitored with VEP recording to assess demyelination and axonal loss along ONs.
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Affiliation(s)
- Valerio Castoldi
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| | - Silvia Marenna
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| | - Su-Chun Huang
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| | - Raffaele d'Isa
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Linda Chaabane
- INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Giancarlo Comi
- Vita-Salute San Raffaele University, Milan, Italy.,Casa di Cura del Policlinico, Milan, Italy
| | - Letizia Leocani
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy.,INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
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Castoldi V, d'Isa R, Marenna S, Comi G, Leocani L. Non-invasive visual evoked potentials under sevoflurane versus ketamine-xylazine in rats. Heliyon 2021; 7:e08360. [PMID: 34816047 PMCID: PMC8591496 DOI: 10.1016/j.heliyon.2021.e08360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/19/2021] [Accepted: 11/05/2021] [Indexed: 11/17/2022] Open
Abstract
Background Visual Evoked Potential (VEP) quantifies electrical signals produced in visual cortex in response to visual stimuli. VEP elicited by light flashes is a useful biomarker to evaluate visual function in preclinical models and it can be recorded in awake or anaesthetised state. Different types of anaesthesia influence VEP properties, such as latency, which measures the propagation speed along nerve fibers, and amplitude that quantifies the power of electrical signal. Aim The goal of this work is to compare VEPs elicited in Dark Agouti rats under two types of anaesthesia: volatile sevoflurane or injectable ketamine-xylazine. Methods VEP latency, amplitude, signal-to-noise ratio and recording duration were measured in Dark Agouti rats randomly assigned to two groups, the first subjected to volatile sevoflurane and the second to injectable ketamine-xylazine. Taking advantage of non-invasive flash-VEP recording through epidermal cup electrodes, three time points of VEP recordings were assessed in two weeks intervals. Results VEP recorded under ketamine-xylazine showed longer latency and higher amplitude compared with sevoflurane, with analogous repeatability over time. However, sevoflurane tended to suppress electrical signals from visual cortex, resulting in a lower signal-to-noise ratio. Moreover, VEP procedure duration lasted longer in rats anaesthetised with sevoflurane than ketamine-xylazine. Conclusions In Dark Agouti rats, the use of different anaesthesia can influence VEP components in terms of latency and amplitude. Notably, sevoflurane and ketamine-xylazine revealed satisfying repeatability over time, which is critical to perform reliable follow-up studies. Ketamine-xylazine allowed to obtain more clearly discernible VEP components and less background noise, together with a quicker recording procedure and a consequently improved animal safety and welfare.
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Affiliation(s)
- Valerio Castoldi
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| | - Raffaele d'Isa
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Silvia Marenna
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Giancarlo Comi
- Vita-Salute San Raffaele University, Milan, Italy.,Casa di Cura del Policlinico, Milan, Italy
| | - Letizia Leocani
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
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11
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Marenna S, Huang SC, Castoldi V, d’Isa R, Costa GD, Comi G, Leocani L. Functional evolution of visual involvement in experimental autoimmune encephalomyelitis. Mult Scler J Exp Transl Clin 2020; 6:2055217320963474. [PMID: 35145730 PMCID: PMC8822451 DOI: 10.1177/2055217320963474] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 09/12/2020] [Indexed: 12/21/2022] Open
Abstract
Background Experimental autoimmune encephalomyelitis (EAE) is a common animal model of multiple sclerosis (MS). C57BL/6 mice immunized with myelin oligodendrocyte glycoprotein exhibit chronic disease course, together with optic neuritis, consisting of demyelination/axonal loss of the optic nerve. Objectives To characterize functional and structural visual damages in two different phases of EAE: pre- and post-motor onset. Methods Visual alterations were detected with Visual Evoked Potential (VEP), Electroretinogram (ERG) and Optical Coherence Tomography (OCT). Optic nerve histology was performed at 7 (pre-motor onset) or 37 (post-motor onset) days post-immunization (dpi). Results At 7 dpi, optic nerve inflammation was similar in EAE eyes with and without VEP latency delay. Demyelination was detected in EAE eyes with latency delay (p < 0.0001), while axonal loss (p < 0.0001) and ERG b-wave amplitude (p = 0.004) were decreased in EAE eyes without latency delay compared to Healthy controls. At 37 dpi, functional and structural optic nerve damage were comparable between EAE groups, while a decrease of ERG amplitude and NGCC thickness were found in EAE eyes with VEP latency delay detected post-motor onset. Conclusions Thanks to non-invasive methods, we studied the visual system in a MS model, which could be useful for developing specific therapeutic strategies to target different disease phases.
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Affiliation(s)
- Silvia Marenna
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy
| | - Su-Chun Huang
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy
| | - Valerio Castoldi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy
| | - Raffaele d’Isa
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy
| | - Gloria Dalla Costa
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy
| | - Giancarlo Comi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy
| | - Letizia Leocani
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy
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12
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Moore D, Ikuta T, Loprinzi PD. The Effects of Human Visual Sensory Stimuli on N1b Amplitude: An EEG Study. J Clin Med 2020; 9:jcm9092837. [PMID: 32887299 PMCID: PMC7564488 DOI: 10.3390/jcm9092837] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 08/30/2020] [Accepted: 08/31/2020] [Indexed: 01/31/2023] Open
Abstract
Sensory systems are widely known to exhibit adaptive mechanisms. Vision is no exception to input dependent changes in its sensitivity. Recent animal work demonstrates enhanced connectivity between neurons in the visual cortex. The purpose of the present experiment was to evaluate a human model that noninvasively alters the amplitude of the N1b component in the visual cortex of humans by means of rapid visual stimulation. Nineteen participants (Mage = 24 years; 52.6% male) completed a rapid visual stimulation paradigm involving black and white reversal checkerboards presented bilaterally in the visual field. EEG data was collected during the visual stimulation paradigm, which consisted of four main phases, a pre-tetanus block, photic stimulus, early post-tetanus, and late post-tetanus. The amplitude of the N1b component of the pre-tetanus, early post-tetanus and late post-tetanus visual evoked potentials were calculated. Change in N1b amplitude was calculated by subtracting pre-tetanus N1b amplitude from early and late post-tetanus. Results demonstrated a significant difference between pre-tetanus N1b (M = −0.498 µV, SD = 0.858) and early N1b (M = −1.011 µV, SD = 1.088), t (18) = 2.761, p = 0.039, d = 0.633. No difference was observed between pre-tetanus N1b and late N1b (p = 0.36). In conclusion, our findings suggest that it is possible to induce changes in the amplitude of the visually evoked potential N1b waveform in the visual cortex of humans non-invasively. Additional work is needed to corroborate that the potentiation of the N1b component observed in this study is due to similar mechanisms essential to prolonged strengthened neural connections exhibited in cognitive structures of the brain observed in prior animal research. If so, this will allow for the examination of strengthened neural connectivity and its interaction with multiple human sensory stimuli and behaviors.
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Affiliation(s)
- Damien Moore
- Exercise & Memory Laboratory, Department of Health, Exercise Science and Recreation Management, The University of Mississippi, University, MS 38677, USA;
| | - Toshikazu Ikuta
- Digital Neuroscience Laboratory, Department of Communication Sciences and Disorders, The University of Mississippi, University, MS 38677, USA;
| | - Paul D. Loprinzi
- Exercise & Memory Laboratory, Department of Health, Exercise Science and Recreation Management, The University of Mississippi, University, MS 38677, USA;
- Correspondence:
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13
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d'Isa R, Castoldi V, Marenna S, Santangelo R, Comi G, Leocani L. A new electrophysiological non-invasive method to assess retinocortical conduction time in the Dark Agouti rat through the simultaneous recording of electroretinogram and visual evoked potential. Doc Ophthalmol 2020; 140:245-255. [PMID: 31832898 DOI: 10.1007/s10633-019-09741-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 12/06/2019] [Indexed: 11/25/2022]
Abstract
PURPOSE To develop a non-invasive method exploiting simultaneous recording of epidermal visual evoked potential (VEP) and epicorneal electroretinogram (ERG) to study retinocortical function and to evaluate its reliability and repeatability over time. METHODS Female wild-type DA rats were anesthetized with ketamine/xylazine (40/5 mg/kg). Epidermal VEP (Ag/AgCl cup electrode on scalp) and epicorneal ERG (gold ring electrode on eye surface) were recorded simultaneously in response to flash stimulation. RESULTS ANOVA for repeated measures showed that peak times of ERG b-wave and of VEP N1 and P2 were stable across 6 weekly time-points, as well as the corresponding amplitudes. Mean retinocortical time from b-wave to N1 (RCT1) was 7.6 ms and remained comparable across the 6 time-points. Mean retinocortical time from b-wave to P2 (RCT2) was 28.7 ms and did not show significant variations over time. Coefficient of variation (CoV%) and CoV% adjusted for sample size, namely relative standard error (RSE%), were calculated as indexes of repeatability. Good RSE% over time was obtained (< 5% for b-wave, N1 and P2 peak times; < 20% and < 7% for RCT1 and RCT2, respectively). CONCLUSIONS Simultaneous recording of ERG and VEP has been previously achieved through invasive methods requiring surgery. Here, we present a new non-invasive method, which allowed to obtain peak and retinocortical times that were constant across a long period and had a good repeatability over time. This method will ensure not only a gain in animal welfare, but will also avoid stress and eye or brain lesions which can interfere with experimental variables.
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Affiliation(s)
- Raffaele d'Isa
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy
| | - Valerio Castoldi
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy
| | - Silvia Marenna
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy
| | - Roberto Santangelo
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy
| | - Giancarlo Comi
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy
| | - Letizia Leocani
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy.
- Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy.
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14
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Castoldi V, Marenna S, d'Isa R, Huang SC, De Battista D, Chirizzi C, Chaabane L, Kumar D, Boschert U, Comi G, Leocani L. Non-invasive visual evoked potentials to assess optic nerve involvement in the dark agouti rat model of experimental autoimmune encephalomyelitis induced by myelin oligodendrocyte glycoprotein. Brain Pathol 2019; 30:137-150. [PMID: 31267597 DOI: 10.1111/bpa.12762] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/25/2019] [Indexed: 12/22/2022] Open
Abstract
Experimental autoimmune encephalomyelitis (EAE) is the primary disease model of multiple sclerosis (MS), one of the most diffused neurological diseases characterized by fatigue, muscle weakness, vision loss, anxiety and depression. EAE can be induced through injection of myelin peptides to susceptible mouse or rat strains. In particular, EAE elicited by the autoimmune reaction against myelin oligodendrocyte glycoprotein (MOG) presents the common features of human MS: inflammation, demyelination and axonal loss. Optic neuritis affects visual pathways in both MS and in several EAE models. Neurophysiological evaluation through visual evoked potential (VEP) recording is useful to check visual pathway dysfunctions and to test the efficacy of innovative treatments against optic neuritis. For this purpose, we investigate the extent of VEP abnormalities in the dark agouti (DA) rat immunized with MOG, which develops a relapsing-remitting disease course. Together with the detection of motor signs, we acquired VEPs during both early and late stages of EAE, taking advantage of a non-invasive recording procedure that allows long follow-up studies. The validation of VEP outcomes was determined by comparison with ON histopathology, aimed at revealing inflammation, demyelination and nerve fiber loss. Our results indicate that the first VEP latency delay in MOG-EAE DA rats appeared before motor deficits and were mainly related to an inflammatory state. Subsequent VEP delays, detected during relapsing EAE phases, were associated with a combination of inflammation, demyelination and axonal loss. Moreover, DA rats with atypical EAE clinical course tested at extremely late time points, manifested abnormal VEPs although motor signs were mild. Overall, our data demonstrated that non-invasive VEPs are a powerful tool to detect visual involvement at different stages of EAE, prompting their validation as biomarkers to test novel treatments against MS optic neuritis.
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Affiliation(s)
- Valerio Castoldi
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy.,University Vita-Salute San Raffaele, Milan, Italy
| | - Silvia Marenna
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy.,University Vita-Salute San Raffaele, Milan, Italy
| | - Raffaele d'Isa
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Su-Chun Huang
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Davide De Battista
- INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Cristina Chirizzi
- INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Linda Chaabane
- INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Deepak Kumar
- EMD Serono Research and Development Institute, Billerica, MA
| | - Ursula Boschert
- Ares Trading S.A., Affiliate of Merck Serono S.A, Eysins, Switzerland
| | - Giancarlo Comi
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy.,University Vita-Salute San Raffaele, Milan, Italy
| | - Letizia Leocani
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy.,University Vita-Salute San Raffaele, Milan, Italy
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