Naked Science Forum
General Science => General Science => Topic started by: sazr on 20/11/2019 21:17:19
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In regards to human vision and specifically the retina and ganglion cells.
Each receptive field is arranged into a central disk, the "center", and a concentric ring, the "surround", each region responding oppositely to light. For example, light in the centre might increase the firing of a particular ganglion cell, whereas light in the surround would decrease the firing of that cell.
I find it hard to comprehend that somehow the light can only hit one part of the retinal ganglion cells (either the centre or the surround) and not the other? Doesn't light go everywhere? Is the lens focusing light so accurately that light is hitting certain parts of a tiny cell (the centre) but not others (the outside/surround)?
Can anyone provide more insight as to how it works that light can hit one tiny part of a tiny cell but not another part of that tiny cell?
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In regards to human vision and specifically the retina and ganglion cells.
Each receptive field is arranged into a central disk, the "center", and a concentric ring, the "surround", each region responding oppositely to light. For example, light in the centre might increase the firing of a particular ganglion cell, whereas light in the surround would decrease the firing of that cell.
I find it hard to comprehend that somehow the light can only hit one part of the retinal ganglion cells (either the centre or the surround) and not the other? Doesn't light go everywhere? Is the lens focusing light so accurately that light is hitting certain parts of a tiny cell (the centre) but not others (the outside/surround)?
Can anyone provide more insight as to how it works that light can hit one tiny part of a tiny cell but not another part of that tiny cell?
Where do you get the quote from? I want to know the context of the statement.
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Where do you get the quote from? I want to know the context of the statement.
On wikipedia, google receptive field:
https://en.wikipedia.org/wiki/Receptive_field#Retinal_ganglion_cells
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This can be explained by assuming that retinal ganglion cells have two photosenitive parts, namely central and peripheral parts. The cells are activated based on difference of light reception between those parts.
(https://upload.wikimedia.org/wikipedia/commons/1/16/Receptive_field.png)
On center cells activate when central part receive light, but reduced/canceled out if the peripheral part also receive light.
On the other hand,
Off center cells activate when peripheral part receive light, but reduced/canceled out if the central part also receive light.