What Is the Left Occipital Lobe?
The left occipital lobe is the left side of the region in the brain responsible for visual perception. It is located at the back bottom portion of the skull, behind the temporal lobe and below the parietal lobe. There are two equal halves of the occipital lobe, and the right and left are similar in composition and behavior. One difference between the left and right occipital lobe is in the presentation of symptoms for lesions in each area.
Divided right and left by the cerebral fissure, the two sides of the occipital lobe are separated by same main line that divides the brain into the left and right cerebrum. There is another division called the calcarine fissure that further separates the top and bottom portions of the right and left occipital lobe. Cases of left side occipital lobe damage have presented with different effects than damage that occurs on the right. The occipital lobe is responsible for vision and eye control, so left side lesions cause rapid eye movement and the loss of the ability to read. In right side damage, along with impaired reading skill, writing ability is also lost.
Most of the time, damage that occurs to either the right or left occipital lobe presents identically. Up to ten percent of epilepsy cases are specific to the area. These types of seizures have visual cues, such as repeated blinking and visual hallucinations. Physicians diagnoses this disorder by exposing a patient to a flashing strobe light and recording an electroencephalography (EEG). Symptoms of left occipital lobe seizures often have the same symptoms of migraine headaches and also cause visualizations and uncontrolled eye movement.
The left occipital lobe is not often damaged due to its location in the back of the head. It is named after the plate of the skull that covers it, the occipital bone. The area is relatively unaffected by dementia and diseases such as Alzheimer's, but it can cause afflicted individuals to misperceive objects.
Color differentiation and the ability to judge movement are key responsibilities of the right and left occipital lobe. Despite location, vision is affected in both eyes when one side of the occipital lobe is damaged. Damage can cause holes to appear in the visual field. The brain is sometimes still able to process information from the hole in vision, much like the brain can still perceive blind spots.
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