I am writing with a query about the primary role of photoreceptor cells in the process of seeing. It is my understanding that photoreceptor cells convert light into electrical signals which are transferred to the brain which processes the image of the original object being viewed. My query is – apart from the difference in voltage what are the other characteristics of the electrical signals which enable the brain to process images of different objects differently. Specifically, since it is not ruled out that different electrical signals into which photoreceptor cells convert light may have the same voltage, what are the other characteristics of these electrical signals which enable the brain to interpret them differently ?
For example, light falls on a wooden box, gets reflected from the box, enters my eyes, photoreceptors in the retina of my eye convert this optical signal into electrical signal and I visualize the box. Now another time light comes from a chair and I visualize a chair. In what sense is the electrical signal due to this box is different than the electrical signal due to the chair? In the electrical signal, how is the information of box/chair is retained?
Thanks, Manish Khare, for your question, as well as initiating the discussion board.
As far as one knows, such electric signals you mentioned interact with rods, being afterwards transmitted to the brain, which interprets what is “seen”.
On the other hand, another type of photoreceptors in the retina, called intrinsically-photosensitive retinal ganglion cells (ipRGCs) also perform other functions, such as setting the body’s light-driven circadian rhythms and distinguishing contrast and color in our visual field, which helps processing images on a different level. Further neuroscience studies are yet to discover the origins of such pathways in these cells.
- Badges
- Science topic