The parietal lobe is one of the major lobes in the brain, roughly located at the upper back area in the skull.
It processes sensory information it receives from the outside world, mainly relating to touch, taste, and temperature.
Damage to the parietal lobe may lead to dysfunction in the senses. There are also some health conditions associated with parietal lobe damage.
Keep reading to learn more.
The parietal lobe is one of the four major lobes of the cerebral cortex in humans. It sits near the upper back portion of the skull, close to the parietal bone.
In the brain, the parietal lobe is located behind the frontal lobe. A boundary called the central sulcus separates the two lobes. The parietal lobe also sits above the temporal lobe, with the Sylvian fissure, or lateral sulcus, separating the two.
The occipital lobe is behind and slightly underneath the parietal lobe. The parieto-occipital sulcus divides these two lobes.
Like the brain itself, the parietal lobe is divided into two hemispheres by the central furrow, or medial longitudinal fissure.
The parietal lobe relies heavily on many other areas of the body to receive information. For example, the skin and nerves in the skin play a large part in detecting sensory information and delivering it to the parietal lobe.
The parietal lobe itself also sends this information to other parts of the brain for interpretation. Many everyday functions require the use of multiple lobes in the brain.
In general, the parietal lobe is a major interpreter of the sensory world around the body. In fact, the parietal lobe is a primary sensory area, which means that it is the starting point of sensory processing within the brain.
The following are some of the main functions of the parietal lobe:
The parietal lobe deals with many sensations, including:
These are the somatic senses, meaning that they come from the body. The information from these senses helps a person form physical sensations taken from the world around them.
In order to carry out this function, the parietal lobe receives sensory information from all over the body.
The parietal lobe also plays a role in a person’s ability to judge size, shape, and distance. Additionally, it helps with the interpretation of symbols. This includes those in written and spoken language, mathematical problems, and codes and puzzles.
Hearing and visual perception, as well as memory, are also part of the parietal lobe’s functions.
Navigation and control
The parietal lobe also plays a role in functions such as navigation and controlling the body, as well as understanding spatial orientation and direction.
A person’s dominant hand will often determine which side of the parietal lobe is more active. A person who is right-handed may have a more active left hemisphere parietal lobe. The left lobe tends to deal more with numbers, letters, and symbols.
The right hemisphere may be more active in people with a dominant left hand. This hemisphere is associated with image interpretation and spatial relationships.
That said, these distinctions do not limit the other side of the lobe. Everyone uses both the right and left sides of the parietal lobe and brain.
The following are some key areas of the parietal lobe:
The somatosensory cortex in the front part of the parietal lobe resides in two areas: the postcentral gyrus and the posterior paracentral lobule.
It helps process and interpret touch sensations and helps discriminate between them. For example, it helps with telling the difference between something that is cold and something that is painful.
Superior parietal lobule
This area of the brain is involved in memory.
It also includes the parietal association cortex, which coordinates and integrates information from all the senses.
Super marginal gyrus
This part of the brain contains part of Wernicke’s area, which is important for speech.
The angular gyrus is a small, triangular area in the parietal lobe.
It helps the brain associate symbols and meaning and assists with word recognition. This gives the brain the ability to assign meaning and name objects in the environment.
It also helps use symbols and language, thus playing a role in abilities such as drawing, reading, and reasoning. This helps a person understand written words and mathematical equations.
Damage to the angular gyrus, on the dominant side, can cause Gerstmann’s syndrome. Gerstmann’s syndrome is characterized by:
- an inability to write
- an inability to perform arithmetic
- difficulty recognizing which finger is which
- trouble differentiating the right from the left side of the body
A few different medical conditions can stem from dysfunction in the parietal lobe. Generally speaking, damage to the parietal lobe may lead to a loss of sensations of touch.
Such damage may be due to:
Damage to the left lobe can cause difficulty with functions related to symbols, such as language, mathematics, and writing.
Damage to the right lobe may lead to difficulty with images, spatial awareness, movement, and the ability to visualize and create.
The following sections will look at some specific conditions associated with parietal lobe damage in more detail.
Parietal lobe syndrome
Parietal lobe syndrome may occur after sustaining damage to one of the parietal lobes.
This tends to cause a few different contralateral symptoms, meaning that the symptoms appear on the opposite side of the body from the lobe that experienced the damage.
Optic ataxia is a condition that causes a loss in the ability to guide the hand and arm with the eye. A person with optic ataxia may seem to grope for an item close to them rather than simply pick it up.
Optic apraxia occurs when a person cannot voluntarily control their visual gaze.
Damage to the front portion of the parietal lobe may make it difficult for a person to recognize objects based on their sense of touch.
Agraphesthesia is another possible outcome of damage to the parietal lobe. A person with this condition cannot detect or identify basic shapes or letters drawn onto their skin.
People with parietal lobe syndrome may also present with sensory inattention. If a person with this condition were to put their hands together, they would not feel the sensation on one of the hands.
Gerstmann’s syndrome occurs when there is lateral damage to the parietal lobe. The syndrome interrupts important functions of the parietal lobe and makes it difficult for a person to distinguish movement and location from left to right.
A person may have difficulty identifying their fingers, and they may be unable to distinguish the left and right sides of their body or surroundings.
People with Gerstmann’s syndrome may also have difficulty with equations, reading, and writing, as they cannot interpret symbols.
Gerstmann’s syndrome may occur due to reduced blood flow in the parietal lobe. It may develop after a stroke or due to another vascular disease in the brain that drastically reduces blood supply.
The syndrome and similar symptoms may also occur with tumors in the parietal lobe or other forms of brain damage.
Contralateral neglect often occurs as a result of damage to the nondominant parietal lobe, which is typically the right lobe in people who are right-handed.
As a result, a person will have less awareness of their nondominant side and the environment around it. A right-handed person with contralateral neglect would be less aware of the left side of their body, for example.
This may lead to burns, bruises, and other injuries.
There are both severe and minor forms of this condition, and symptoms may vary greatly.
Balint syndrome is a rare disorder that occurs due to damage to both sides of the parietal lobe.
It encompasses many of the above symptoms and generally causes both visual and spatial difficulties, including symptoms such as optic ataxia, optic apraxia, and simultanagnosia. Simultanagnosia is the inability to take in multiple elements from the visual environment.
The parietal lobe is one of the four major lobes of the cortex.
It is primarily responsible for sensations of touch, such as temperature and pain, but it also plays a role in numerous other functions.
A number of conditions can occur due to dysfunction in or injury to the parietal lobe. These include Balint syndrome, Gerstmann’s syndrome, and asterognosis.