April 30, 2012


The eye is the brain. Light shines through neurons before it is detected and interpreted at an early stage before further processing at higher levels in the brain, proper.



Rods, cones and nerve layers in the retina. The front (anterior) of the eye is on the left. Light (from the left) passes through several transparent nerve layers to reach the rods and cones (far right). A chemical change in the rods and cones send a signal back to the nerves. The signal goes first to the bipolar and horizontal cells (yellow layer), then to the amacrine cells and ganglion cells (purple layer), then to the optic nerve fibers. The signals are processed in these layers. First, the signals start as raw outputs of points in the rod and cone cells. Then the nerve layers identify simple shapes, such as bright points surrounded by dark points, edges, and movement. (Based on a drawing by Ram?n y Cajal.)

(Emphasis Mine.)

Bight points surrounded by dark points.



Posted by Dennis at April 30, 2012 6:28 PM

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