TY - JOUR
T1 - 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
AU - d’Isa, Raffaele
AU - Castoldi, Valerio
AU - Marenna, Silvia
AU - Santangelo, Roberto
AU - Comi, Giancarlo
AU - Leocani, Letizia
N1 - Funding Information:
This work was carried out within the framework of the NeOn project (ID 239047) with the financial support of Regione Lombardia (POR FESR 2014 – 2020) and the Ivascomar project of the Italian Ministry of Education, University and Research (CTN01_00177_165430), Cluster Tecnologico Nazionale Scienze della Vita “Alisei”.
Publisher Copyright:
© 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/6/1
Y1 - 2020/6/1
N2 - 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.
AB - 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.
KW - Animal welfare
KW - Electroretinogram
KW - Epidermal cup electrodes
KW - Non-invasive electrophysiology
KW - Retinocortical time
KW - Visual evoked potential
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U2 - 10.1007/s10633-019-09741-3
DO - 10.1007/s10633-019-09741-3
M3 - Article
C2 - 31832898
AN - SCOPUS:85076357477
VL - 140
SP - 245
EP - 255
JO - Documenta Ophthalmologica
JF - Documenta Ophthalmologica
SN - 0012-4486
IS - 3
ER -