The brain is divided into four major lobes based on their location in the human skull: parietal, frontal, temporal, and occipital. The lobes are the major regions of the cerebral cortex that serve as centers for processing sensory information.
The parietal lobe, as one of those centers, is one of the most vitally important lobes in the brain because it controls numerous functions of the human body. To receive and process sensory information is the parietal lobe’s main function.
Where Is the Parietal Lobe Located in the Brain?
The parietal lobe is located right under the parietal bone of the skull, hence its name. It takes a top central position in the cerebral cortex, above the occipital and temporal lobe, and behind the frontal lobe.
Anatomy and Structure of the Parietal Lobe
Since the brain is divided into a left and right hemisphere, the parietal lobe is also divided into the left and right parietal lobe by the medial longitudinal fissure (or interhemispheric fissure). The brain sulci (folds), gyri (furrows), and lobules (small parts) give the parietal lobe its specific structure.
The parietal lobe consists of three elements (divisions):
- postcentral gyrus
- superior parietal lobule
- inferior parietal lobule
Postcentral Gyrus
The postcentral gyrus is a fold on the surface of the brain, comprising the area of the cerebral cortex where the somatosensory signals and information are received and regulated.
This part of the somatosensory cortex is responsible for the detection of touch, the position of our body in the space around us, the feeling of pain, as well as the feeling and regulation of our temperature.
In addition, the postcentral gyrus is the main sensory center for the ability to sense touch.
How is touch recognized in the brain?
Our skin consists of many receptors that receive the information of the object we touch (or from the environment, in general).
Then, the information received from the sensory organ of touch travels through the neurons which transform it into a signal and reaches the central nervous system. Here, the neurons activate the receptors’ action potential and send signals.
First, they send them to the spinal cord and the brain, from which the signals of touch are sent to the specialized centers for processing sensory information. In the case of the signal of touch, this is the parietal lobe, or – to be more precise – the big fold on the brain cortex called postcentral gyrus.
Superior Parietal Lobule
The superior parietal lobule is the main area in the human brain which is responsible for our spatial awareness. This part of the brain combines and coordinates all the information from the other parts of the body.
Brodmann’s areas 5 and 7
These areas are located in the superior parietal lobule, and are defined by the number and organization of its cells.
Thus, Brodmann’s area 5 is a subdivision of the parietal lobe, located right behind the primary somatosensory cortex of the brain. It is responsible for processing the information received through the senses of touch, taste, smell, touch, and hearing.
Also, this area of the parietal lobe helps us with the orientation in space, and also helps the body regulate movement.
Brodmann’s area 7 is the location on the parietal lobe of the brain cortex responsible for our spatial coordination. It helps us determine the distance and relation between our body and the objects in space, aiding our spatial coordination.
Inferior Parietal Lobule
This is the brain area where language, mathematical operations, facial expressions, as well as the interpretation of the sensory information are processed and controlled.
The inferior parietal lobule consists of a supramarginal gyrus and an angular gyrus. Its main function is to gather and coordinate the information collected from the senses of smell, taste, touch, sight, and hearing.
Furthermore, the inferior parietal lobule helps us maintain our focus and orient our body in the space around us, and control and regulate the information received through the retina of our eyes, as well as the audio-messages coming to the brain from the organs of hearing.
Anatomical Borders of the Parietal Lobus
The parietal lobe has three anatomical boundaries:
- central sulcus
- parieto-occipital sulcus
- lateral sulcus
Central Sulcus
The central sulcus (fold) separates the parietal lobe from the frontal lobe. It also separates the primary motor cortex from the primary somatosensory cortex, i.e it divides the sensory and the motor areas of the brain.
This border of the parietal lobe contains a type of neuronal matching map of both the left and right sides of the body, which serves to identify the other parts of the cortex of the brain.
Parieto-occipital Sulcus
The parieto-occipital sulcus (fold) separates the parietal lobe from the occipital lobe in both brain hemispheres. It also defines the location of the primary visual cortex, which makes it a very important landmark in the cortex of the brain.
Lateral Sulcus
This brain fold is one of the deepest and most prominent of the brain cortex sulci. The lateral sulcus is located under the frontal and parietal lobe, dividing them from the temporal lobe located below this fold in both of the brain hemispheres.
The lateral sulcus is also called Sylvian fissure (or lateral fissure). It separates the centers of processing emotion, problem-solving, and decision making from the centers regulating the cognitive processes, such as learning, memory, and language.
What Is the Function of the Parietal Lobe?
The parietal lobe is one of the most important centers for integration of sensory impulses in the brain. It receives and processes sensory information from the body and skin, and coordinates the information received from all the other parts of the brain.
The list of parietal lobe functions includes the regulation and control of the following processes:
- Speech
- Reading
- Writing
- Cognition
- Spatial orientation
- Navigation
- Visual perception
- Sensation of pain
- Sensation of touch
- Sensation of smell
- Sensation of taste
- Sensation of hearing
- Coordination of movements
- Mathematical computation
- Regulation of temperature
- Distinguishing size, shape, and color
The Left Parietal Lobe
The left part of the parietal lobe is more active in right-handed people, since the left hemisphere of the brain controls the right side of our body.
It processes memories, cognitive, and sensory information received through the nerve impulses and gives them meaning.
The Right Parietal Lobe
Similarly to the left parietal hemisphere, the right parietal lobe is more active in the left-handed people, due to the fact that the right hemisphere of the brain controls the left side of the body.
The main function of this part of the brain is to help us with the recognition and interpretation of the images and objects, as well as with the spatial distances.
What Happens When the Parietal Lobe Is Dysfunctional?
After an inflicted injury to the parietal lobe, the following problems can occur:
- Difficulties in reading, writing, and comprehension
- Visual impairment
- Motor skill problems
- Difficulty in distinguishing left from right
- Immediate memory impairment
- Eye-movement problems
- Problems with spatial orientation
- Problems with eye-hand coordination
- Difficulty with mathematics
- Lack of awareness or neglecting some parts of the body
To continue with, there are also some more serious medical conditions which can appear as a result of an injury to the parietal lobe:
- Ataxia – a movement disorder that affects coordination, movement, speech, and balance. The symptoms of ataxia include behavior or personality changes, dizziness, fatigue, change of voice, low muscle tone.
- Aphasia – a disorder affecting our speech. It always occurs due to severe damage or inflammation of the brain, or due to a tumor. Aphasia results with loss of the ability to speak, write, and read, and with a lack of words. However, intelligence is not affected by it.
- Alexia – is a disorder when the affected individual loses the ability to both read and understand written words due to a brain injury.
- Visual or tactile agnosia – a disorder characterised by an inability to recognize objects, shapes, colors, persons, and sounds, without having suffered a memory loss.
- Dyscalculia – a disorder of the brain which triggers a lack of focus (or concentration), as well as difficulty in understanding mathematical concepts, losing track when counting, inability to calculate numbers or read an analog clock, etc.
- Gerstmann’s Syndrome – a very rare and complex cognitive impairment caused by an injury to a specific part in the left parietal lobe. It consists of four neuropsychological disorders: acalculia (inability to calculate), finger agnosia (inability to recognize the fingers on the hand), left/right confusion (inability to tell left from right), and agraphia (inability to write).
To Sum Up
Located in the middle part of the brain, the parietal lobe represents the center of the somatic senses, which include the recognition and appreciation of touch, bodily posture, and the position of the extremities. It helps us identify the spatial relationships and the world around us by recognizing objects, faces, colors, sounds, smells, tastes, distances, and patterns.
Also, we’d be literally lost without a healthy and properly functional parietal lobe, as it governs our sense of orientation in space by allowing us to analyze and decide on the position and distance of our body in the space that surrounds us, in relation to another person or object.
Moreover, the parietal lobe plays an important function in the learning, understanding, and reproduction of a language. Furthermore, it is very important for the interpretation of pain, temperature, visual information, the ability to compute, tell left from right, as well as for the motor-sensory signals.
In case this part of the brain located in the central part of the cortex suffers an injury, it can lead to severe medical conditions, disorders, and syndromes, such as problems with spatial orientation, eye-movement, eye-hand coordination, understanding of both spoken and written words, reading, control of fingers, loss of smell and taste, etc.
Fun Facts
Did you know?
- The parietal lobe is the ‘captain’ of our body, because it controls our sense of navigation, direction, and orientation in space.
- We all get lost sometimes when we are in unfamiliar territory, but the parietal lobe comes to our rescue by controlling and regulating our orientation in the space around us.
- This part of the brain is named after the bone in the skull which protects it. In Latin, pariet means ‘wall’.
- If you are a talented ballet dancer, gymnast, mathematician, or you love and speak several foreign languages, feel free to thank the parietal lobe for regulating and being in control of your brilliant skills.
- Also, if you are one of those persons who like to listen to their favorite music, browse the feed on the phone and eat a meal at the same time, it’s good to know that the parietal lobe is helping you organize all those small tasks and perform them simultaneously.
- An injury to the left parietal lobe can affect our verbal memory, as well as the ability to memorize a string of digits.
- An injury to the right parietal lobe can result in the impairment of our self-care skills, such as maintaining personal hygiene and dressing.
- If it wasn’t for the parietal lobe, we would not be able to feel a hug, for instance. Similarly, we wouldn’t care if our tea is hot or cold.
- An injury of the parietal lobe can cause a problem with the recognition of an object via the sense of touch.
- The role of the parietal lobe depends on the volume of information that we receive via the organs of touch, smell, sight, taste, and hearing.