Brain
Parietal Lobe
Spatial awareness and sensory integration
Overview
The parietal lobe sits behind the frontal lobe and above the temporal lobe. Its primary role is processing somatosensory information—touch, pressure, pain, temperature, and proprioception. It also integrates sensory data to create spatial awareness, navigate environments, and recognize objects by feel.
Function
- Processes touch, pressure, and pain signals
- Spatial orientation and navigation
- Integrates sensory information from different modalities
- Hand-eye coordination
- Number processing and arithmetic
Key Facts
- The somatosensory cortex maps the body surface (homunculus)
- Damage to the right parietal lobe can cause hemispatial neglect
- Albert Einstein's parietal lobes were 15% wider than average
- The angular gyrus links language and number processing
Key Substructures
- Primary somatosensory cortex (S1, postcentral gyrus): touch, pressure, and proprioception
- Superior parietal lobule (SPL): spatial awareness, tool use, and body schema
- Inferior parietal lobule (IPL): angular gyrus and supramarginal gyrus for language and calculation
- Angular gyrus: reading, writing, and arithmetic; cross-modal associations
- Intraparietal sulcus: number sense and visuospatial working memory
Clinical Notes
- Right hemisphere damage causes hemispatial neglect: ignoring the left side of space
- Gerstmann syndrome (left parietal): finger agnosia, acalculia, alexia, agraphia
- Ideomotor apraxia: cannot imitate or pantomime learned skilled movements
- Damage to angular gyrus impairs reading (alexia) and writing (agraphia)