Assessment of the Absolute Excitatory Level of the Retina by Flicker ERG.
Methods Mol Biol
; 1753: 191-202, 2018.
Article
in En
| MEDLINE
| ID: mdl-29564790
ABSTRACT
Electroretinography (ERG) is important for functional diagnostics of the retina. Types of information about retinal function obtainable by ERG differ depending on recording conditions, e.g., a combination of light stimulus and adaptation. In terms of stimulation, single-flash and flicker stimuli are frequently used because response properties have been well investigated, allowing an assessment of fundamental retinal functionality; for example, how photoreceptors and bipolar cells, including signal transmission between them, are affected under pathological conditions. Usually, ERGs are recorded with a nonzero lower cutoff frequency of amplifiers to avoid certain artifacts, and additionally, responses are averaged over time so that non-event-related signals are cancelled out. However, the improved signal quality is associated with a loss of information. Especially in steady-state flicker ERG, information about the absolute baseline of recordings is missing because the prestimulus baseline is not included on the recording trace as well as because a zero response is obtained in all cases in which the signal baseline stays constant for a sufficient amount of time. In other words, it is impossible to tell from the conventional flicker ERG whether a zero signal is obtained under conditions of maximal or no excitation of the visual system. In this chapter, we describe a direct current ERG protocol (featuring a lower cutoff frequency of zero) with repetitive single flashes mimicking conventional flicker that contains a defined onset. Using this recording protocol, it is possible to assess not only the absolute excitatory level of the retina but also the development of steady-state responses from the single flash response.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Photic Stimulation
/
Retina
/
Electroretinography
Type of study:
Guideline
Limits:
Animals
Language:
En
Journal:
Methods Mol Biol
Journal subject:
BIOLOGIA MOLECULAR
Year:
2018
Document type:
Article
Affiliation country:
Germany