Evaluation of micro Electroretinograms Recorded with Multiple Electrode Array to Assess Focal Retinal Function.

Area of Science:

• Neuroscience
• Ophthalmology
• Physiology

Background:

• Full-field electroretinograms (ERGs) assess overall retinal function.
• Focal ERGs evaluate specific retinal areas.
• A need exists for methods to assess focal retinal function in pathological conditions.

Purpose of the Study:

• To evaluate the utility of a multiple electrode array (MEA) system for recording ex vivo micro-electroretinograms (mERGs).
• To assess focal retinal function and retinal ganglion cell (RGC) responses in isolated mouse retinas.
• To investigate the application of mERGs in studying retinal degeneration and regenerative processes.

Main Methods:

• Recording ex vivo micro-electroretinograms (mERGs) using a multiple electrode array (MEA) system.
• Measuring multiunit spike responses of retinal ganglion cells (RGCs).
• Utilizing pharmacological agents (L-AP4, PDA) to block specific retinal pathways and receptors.

Main Results:

• mERGs successfully recorded a- and b-waves, similar to full-field ERGs.
• Pharmacological blockade confirmed the origin of mERG components and RGC responses.
• mERGs were recordable in rd1 mice with retinal degeneration, where full-field ERGs were non-recordable.
• Analysis of rd1 mice revealed that the negative wave originates from second or third-order neurons, not photoreceptors.

Conclusions:

• The MEA system for mERG recording is valuable for assessing focal retinal function in isolated retinas.
• This technique is particularly useful for studying retinas with pathology and monitoring recovery in regenerative studies.
• mERGs provide insights into the cellular origins of retinal responses, aiding in understanding retinal degeneration mechanisms.