Abstract
Purpose: :
To document a visual recording system that enables conjoint recordings of the eye and brain visual responses from conscious animals.
Methods: :
The basic elements of a novel system for electroretinogram (ERG) and visual evoked potential (VEP) recordings were an electrode detector implantable in the eye, a visual stimulator and a controller of light quantity / controller of colorimetric wavelenght composition of light. The visual voltage signals were conveyable either through the wires or telemetrically to the registering units.
Results: :
With this visual recording system comparative quantitative analyses demonstrated that the degree of photoreceptor damage as caused by the two different retinal degeneration models (i.e. the light and P23H genetic lesions) were correlative with the degree of reductions in both the eye's ERG and tectum's VEP responsiveness to flash stimulations, that ERGs and VEPs were both reliably and with small variations recordable from conscious rats, and that conjoint ERG and VEP records may provide information about the functioning of the optic nerve. Regarding the latter analyses provide further support for the idea that the information of a given light response bias of photoreceptors is quantitatively mediated from the eye to the superior colliculus, through the optic nerve. Because, normally, the properties of light undoubtedly control the light response bias of the retinal photoreceptors, the properties of light directed at the eye should become quantitatively mediated as well, through this visual track, and this point is supported by the present data. The two fatcts in combination, given that they apply for the sum responses of the retina and brain networks, may be hypothetisized to apply for the mutually differing and individual retina-to-brain channels (e.g. the on- and off-paths) as well.
Conclusions: :
The system presented can be used to measure the natural visual functioning of the eye, brain and optic nerve.
Keywords: electrophysiology: non-clinical • electroretinography: non-clinical • pathology: experimental