What Is the Difference between the Occipital and Parietal Lobes?

The occipital and parietal lobes are the two hindmost structures of the brain's cerebrum. Despite being adjacent, the occipital and parietal lobes have some separate specialized functions, mainly processing visual input or receiving other sensory information, respectively. Brain damage and certain neurological conditions can alter these functions or eliminate them altogether, resulting in problems like vision loss or impaired sensorimotor skills, which can profoundly impact patients’ lives.

As the brain's control center and largest structure, the cerebrum is often what people think of as the entire brain. Lengthwise, it consists of two halves, or hemispheres, both of which can be further divided into four lobes. On both the left and right side of the brain, the parietal lobes stretch from the middle of the cerebrum until they meet the occipital lobes, which are located behind and somewhat beneath the parietal lobes. The functions of the occipital and parietal lobes are similar in that they both relate to sensory input, but, based on what is known about the brain as of 2011, the occipital lobes are more singular in terms of what they do.

Within the occipital lobes is the visual cortex, so these lobes perform much of the brain's visual processing. When the eyes view something, the occipital lobes receive the information and connect it to images already stored in memory, allowing humans to discern shapes and colors. The visual processing specific to reading and recognizing faces and objects, however, takes place in the parietal lobes. Other sensory information gathered through taste, touch, temperature, and movement is processed by the parietal lobes alone.

Similar to the visual cortex, the primary sensory cortex is located in the parietal lobes. Thus, common activities and experiences activate this area of the brain, such as the texture and aroma of food. When the body touches something that is too hot, the parietal lobes recognize the danger and signal the muscles to react. The parietal lobes also help with certain cognitive functions, particularly those involving arithmetic. Damage sustained by the occipital and parietal lobes can affect the brain's ability to perceive and process sensory information or perform cognitive tasks.

Accidents cause more injuries to the occipital and parietal lobes, and all other areas of the brain, than any other phenomenon. Seizure disorders, brain lesions, strokes, and infections are among the many medical ailments that can also affect neurological functioning. Occipital lobe damage almost exclusively affects some aspect of vision, causing such problems as color-blindness, or partial and total blindness, as well as the inability to discern certain visual stimuli, such as two different shapes or faces. Parietal lobe damage can cause several sensory or sensorimotor issues including numbness, difficulty perceiving sensations, problems with reading and drawing, or lack of awareness or care for one's own body.