What is Posterior Parietal Cortex?
The posterior parietal cortex (PPC) is a region of the parietal lobe that integrates sensory information for spatial representation, attention, and the planning of actions. It creates and maintains spatial maps.
Key Functions
- •Spatial maps — representation of body and environment
- •Attention — directing attention in space
- •Sensorimotor integration — linking perception to action
- •Body schema — sense of body position and boundaries
Why does the Posterior Parietal Cortex matter?
The posterior parietal cortex matters because it combines information from vision, touch, and body position to build a sense of where things are in space. This lets people reach for objects, navigate, and direct attention to the right place.
It serves as a bridge between perception and action. It also supports some aspects of numerical thinking and the planning of movements before they are carried out.
What happens when the Posterior Parietal Cortex goes wrong?
When the posterior parietal cortex is damaged, people often have trouble with spatial awareness and coordinated movement. A well-known result of damage on the right side, often after a stroke, is hemispatial neglect: a person ignores the left side of space, for instance eating only from one side of a plate or not noticing people on that side.
Damage can also cause optic ataxia, difficulty reaching accurately for objects that are seen, and apraxia, trouble performing skilled movements despite normal strength. When both sides are affected, Balint's syndrome may occur, which makes it hard to perceive more than one object at a time. These symptoms have taught researchers much about how the brain maps space.
In ONDA Life
Part 9 engages the PPC for "assembling spatial maps and placing the image within the environmental context." It synchronizes the mental sketch with the body's physiological response — the vision becomes grounded in space.