Parietal Lobe

What is the Parietal Lobe?

The parietal lobe is one of the four main lobes of the cerebral cortex, the outermost layer of the brain. It is located near the upper, back portion of the brain, between the frontal and occipital lobes. The parietal lobe is essential for processing sensory information from various parts of the body and plays a critical role in spatial awareness, coordination, and integration of sensory input.

Functions

• Somatosensory Processing

  The primary somatosensory cortex, located in the postcentral gyrus of the parietal lobe, receives and processes sensory information from the skin, muscles, and joints. This area is responsible for processing touch, pain, temperature, and proprioception (awareness of body position).

• Spatial Awareness

  The parietal lobe plays a crucial role in spatial awareness, helping individuals understand the position and location of objects and their own body in relation to the environment. This function is particularly important for activities requiring hand-eye coordination and navigation.

• Integration of Sensory Information

  The parietal lobe integrates sensory information from different modalities, such as vision, touch, and hearing, to create a coherent perception of the environment. This integration enables the brain to understand and respond appropriately to complex sensory stimuli.

Associated Disorders

• Gerstmann Syndrome

  Gerstmann Syndrome is a rare neurological disorder associated with damage to the parietal lobe, often involving the dominant inferior parietal region and its connections. It is characterized by a combination of symptoms, including finger agnosia (inability to distinguish fingers), acalculia (difficulty with arithmetic), left-right disorientation, and agraphia (difficulty with writing).

• Apraxia

  Apraxia impairs learned purposeful actions and can result from damage to a wider network that includes parietal regions. Individuals with apraxia may have difficulty performing everyday activities, such as buttoning a shirt or using a tool, despite having intact muscle function and understanding of the task.

• Hemispatial Neglect

  Hemispatial neglect, also known as unilateral neglect or spatial neglect, is a condition in which an individual is unable to attend to one side of their environment, often following right-hemisphere injury affecting distributed attention networks, including parietal, temporal and frontal regions. This can result in difficulties with tasks that require spatial awareness and attention, such as reading, dressing, or navigating through a room.

Why it matters

Reaching for a cup requires information about the cup's position and your own hand. Parietal regions contribute to this sort of sensory and spatial coordination. The disorders above help reveal these functions, but none can be reduced to a single isolated brain region.

Sources and evidence

• OpenStax: Anatomy and Physiology 2e: The Central Nervous System. Introductory anatomy; not all functions are localized to a single structure.
• Maurizio Corbetta and Gordon L. Shulman: Spatial Neglect and Attention Networks. Neglect is not uniquely diagnostic of parietal injury.
• Joseph V. Campellone and A.D.A.M. editorial team: Apraxia. The syndrome has multiple forms and cannot be reduced to one lobe.