Parietal lobe

Your brain has a special part.

This part helps you feel the world. It tells you if things are hot or cold. It helps you feel pain. It also helps you know where your body is.

This part helps you find things. It helps you use your hands to grab objects. It can even help you with numbers. It helps you read and write, too. It is a very busy part of your brain!

Your brain has four main parts. One of these is the parietal lobe.

This part sits above the temporal lobe. It is behind the frontal lobe. The name comes from the parietal bone. This bone is named after the Latin word for "wall."

The parietal lobe helps you feel the world. It takes signals from your skin. These signals include touch, heat, and pain. These signals travel to the lobe through a part called the thalamus.

This part also helps you move. It uses a "where" stream of vision. This helps you know where objects are in space. It helps you guide your eyes and your hands. This way, you can reach out and grab things.

It also helps with many tasks. It helps you work with numbers. It helps you read and write. Some parts help you know where your body parts are. This is called spatial awareness. Without it, you might not know where your limbs are in space.

The parietal lobe is one of the four main parts of the cerebral cortex. It sits above the temporal lobe and behind the frontal lobe.

This part of the brain is very important for how we feel the world. It helps us understand where our body is in space. It also helps us know where objects are located around us. The name comes from the parietal bone. This name comes from the Latin word "paries," which means "wall."

This part of the brain works by bringing different signals together. First, your skin feels things like touch, heat, or pain. These signals travel through a part called the thalamus to reach the parietal lobe.

The lobe then uses these signals to help you recognize shapes. You can even recognize letters drawn on your skin just by feeling them. This is called graphesthesia. The brain also uses a "where" stream of vision. This helps you see where things are so you can move toward them.

Scientists have studied how this part of the brain is shaped for a long time. They use a special idea called a cortical homunculus to show how it works. This is a Latin term that means "little man."

It is a drawing that shows how much of the brain is used for different body parts. If a body part has a lot of feeling, it gets a huge space in the brain. This helps us see how the somatosensory cortex is organized. It is a way to map out how we feel our whole body.

There are many specific areas within the parietal lobe. The central sulcus is a groove that separates it from the frontal lobe. The parieto-occipital sulcus separates it from the occipital lobe.

The lateral sulcus separates it from the temporal lobe below. Inside the lobe, there are parts called the superior and inferior parietal lobules. These areas are very important for knowing where your body is. Some parts, like the AIP area, help you grasp and move objects with your hands.

Understanding the parietal lobe helps us learn about how the brain can change. If this part of the brain is hurt, it can cause many different things. For example, some people might have trouble with math or reading. This is often seen if the left side is affected.

Other people might experience hemispatial neglect. This means they might not notice things on one side of their world. Even if they can see things, their brain does not pay attention to them. This shows how much we rely on this lobe every single day.

The parietal lobe is one of the four major lobes of the cerebral cortex. It is a vital part of the brain responsible for integrating sensory information. This lobe helps us understand our spatial sense and navigation, often called proprioception. It also serves as the main area for processing the sense of touch. By combining different types of signals, the parietal lobe allows us to interact with the world.

The mechanism of the parietal lobe involves a complex relay of information. Sensory inputs from the skin, such as touch, temperature, and pain, travel first to the thalamus. The thalamus then sends these signals to the parietal lobe for processing. Within the lobe, the somatosensory cortex acts as a primary receptive area. This area is located in the postcentral gyrus, just behind the central sulcus. This process allows for functions like two-point discrimination, which is the ability to feel two distinct points through touch alone. It also enables graphesthesia, the ability to recognize writing on the skin by touch.

Anatomically, the parietal lobe is defined by three distinct boundaries. The central sulcus separates it from the frontal lobe. The parieto-occipital sulcus marks the boundary between the parietal and occipital lobes. Finally, the lateral sulcus, also known as the sylvian fissure, separates it from the temporal lobe. The longitudinal fissure divides the two brain hemispheres. Within each hemisphere, the somatosensory cortex represents the skin area on the opposite, or contralateral, side of the body.

The structure of the lobe is divided into several specialized parts. The postcentral gyrus is the most anterior part of the lobe. Behind this lies the posterior parietal cortex, which is divided by the intraparietal sulcus (IPS). This sulcus creates the superior parietal lobule and the inferior parietal lobule. These areas are essential for body and spatial awareness. The IPS and its adjacent areas are further divided into four specific regions: the medial (MIP), lateral (LIP), ventral (VIP), and anterior (AIP) areas. These regions help guide the movement of the eyes and limbs.

Scientists use the term cortical homunculus to describe how the somatosensory cortex is organized. This Latin term means "little man." It is a distorted figure used to illustrate how much brain space is devoted to different body parts. Parts of the body that require high sensitivity occupy much larger areas of the cortex. This concept helps researchers visualize the mapping of the body within the brain.

Research in the 1990s using macaques provided deep insights into the posterior parietal cortex. This area is often called the dorsal stream of vision, or the "where" and "how" stream. The LIP area contains a map of neurons representing spatial locations and attention. The VIP area receives input from visual, somatosensory, auditory, and vestibular senses to represent space. The MIP area encodes the location of reach targets using eye-centered coordinates. Finally, the AIP area contains neurons responsive to the shape and size of objects. This allows for the precise grasping and manipulation of objects through motor and visual inputs.

Damage to the parietal lobe, known as a lesion, can result in significant clinical symptoms. If the damage is in the dominant hemisphere, it may cause conduction aphasia, dyslexia, or Gerstmann syndrome. Gerstmann syndrome is characterized by agraphia, acalculia, finger agnosia, and left-right disorientation. Damage to the non-dominant hemisphere can lead to hemispatial neglect. This is a condition where a person fails to attend to one side of their space. They may also experience anosognosia, which is a lack of awareness of their own disability.

Bilateral damage, affecting both sides, can lead to Bálint's syndrome. This involves a loss of imagery and difficulty visualizing spatial relationships. Other serious effects include apraxia, a disorder of motor control, and optic ataxia. Optic ataxia makes it difficult to reach for objects in the visual field opposite the damage. The parietal lobe also connects to broader cognitive functions like declarative memory. While damage to the inferior parietal lobe does not cause amnesia, it can diminish memory strength and make retrieving complex details much harder.