Vision

Did you know that the left half of all images you look at registers in your right hemisphere ? On the other hand the right half of your view registers in your left hemisphere.

A comparable arrangement relates to movement and touch. (Each half of the cerebrum is accountable for the conflicting half of the body) There is much known about how cells code visual information into the retina. These studies have given us the best example of how the brain processes information.

The retina consists of three periods of neurons. The first one is the layer of rods and cones. The rods and cones send signals to the mid layer, from the mid layer the signals are then relayed to the third layer. Once reciveing the signal the third layer assembles and forms the optic nerve. The section that contains the first, mid, and third layer is called the receptive field.

Around the 1950's scientists discovered that the receptive field was activated when light hits a small section in its receptive field center and is inhibited when light comes in contact with part of the receptive field around the center.

In the occipital lobe (the primary visual cortex) is two millimeters wide and densely crammed with cells in many sheets that receive messages from the lateral geniculate. Scientists found patterns similar responses to that of the lateral geniculate in the middle layer. (the layer that messages first arrive).

After some recent discoveries, it is theorized that visual signals are fed into at least three separate processing systems. One of these processing systems appears to process shape, the second processes color; and the third process movement and location.

The cornea and the lens help produce a clear image of the object in which they are looking at. The photoreceptors located on the back of the eye are called the retina.

The retina's images that it views are reversed. (Objects to the right of center project images to the left part of the retina and vice versa.)

The rods and cones are visual receptors that turn light into electrical signals. The rods detect dim light were as cones detect bright light and colors. The human eye contains three different types of cones that detect red, green and blue.

The rods and cones are connected with a middle cell layer and a third layer. The light passes through these sections before if finally reaches the optic nerve and the visual cortex were it is deciphered.

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