Documenta Ophthalmologica

, Volume 136, Issue 3, pp 165–175 | Cite as

Visual evoked potentials can be reliably recorded using noninvasive epidermal electrodes in the anesthetized rat

  • Roberto Santangelo
  • Valerio Castoldi
  • Raffaele D’Isa
  • Silvia Marenna
  • Su-Chun Huang
  • Marco Cursi
  • Giancarlo Comi
  • Letizia Leocani
Original Research Article



Visual evoked potentials (VEPs) are a powerful tool to evaluate nervous conduction along the visual pathways, both in humans and in animal models. Traditionally, epidural screw electrodes are used to record VEPs in preclinical research. Here we tested the feasibility in the preclinical setting of the same noninvasive technique used for clinical VEP acquisition, by using epidermal cup electrodes with no surgical procedures.


Monocular flash VEPs were recorded bilaterally under sevoflurane anesthesia once a week for 6 weeks in 14 dark Agouti rats, 7 with implanted epidural screws and 7 with epidermal 6 mm Ø Ag/AgCl cups.


VEP traces obtained with the two techniques were morphologically comparable. There were no significant differences in latency of the main visual component between screw-recorded VEPs (sVEPs) and cup-recorded VEPs (cVEPs). Amplitude values with epidermal cups were significantly lower than those with epidural screws. Both techniques provided latencies and amplitudes which were stable over time. Furthermore, with regard to latency both methods ensured highly repeatable measurements over time, with epidermal cups even providing slightly better results. On the other hand, considering amplitudes, cVEPs and sVEPs provided fairly acceptable repeatability.


Epidermal cup electrodes can provide comparable results to those obtained with the “gold standard” epidural screws, while representing a simpler and less invasive technique to test nervous conduction along the visual pathways in the preclinical setting.


Visual evoked potentials Preclinical visual pathway assessment Epidermal cup electrodes Epidural screw electrodes Noninvasive electrophysiology Animal welfare 



Visual evoked potentials




Within-subject (inter-session) Bland–Altman coefficient of repeatability


Within-subject (inter-session) standard error of the mean


Within-subject (inter-session) coefficient of variation


Within-subject (inter-session) standard deviation



The Italian Ministry of Education, University and Research provided financial support through the cluster project IVASCOMAR (identification, validation and commercial development of new diagnostic and prognostic biomarkers for complex trait diseases; CTN01_00177_165430). The sponsor had no role in the design or conduct of this research.

Compliance with ethical standards

Conflict of interests

All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements) or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.

Informed consent

This article does not contain any studies with human participants performed by any of the authors.

Statement of human rights

This article does not contain any studies with human participants performed by any of the authors.

Statement on the welfare of animals

All applicable international, national and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Roberto Santangelo
    • 1
    • 2
  • Valerio Castoldi
    • 1
    • 2
  • Raffaele D’Isa
    • 1
  • Silvia Marenna
    • 1
    • 2
  • Su-Chun Huang
    • 1
    • 2
  • Marco Cursi
    • 1
  • Giancarlo Comi
    • 1
    • 2
  • Letizia Leocani
    • 1
    • 2
  1. 1.Department of Neurology and Institute of Experimental Neurology (INSPE) - IRCCS-San Raffaele HospitalMilanItaly
  2. 2.University Vita-Salute San Raffaele - IRCCS-San Raffaele HospitalMilanItaly

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