Cortical area · one in each half of the brain

Precuneus

The brain's hidden inner eye for memories, imagination and your sense of self.

The precuneus is tucked away on the inner surface of the parietal lobe, facing the other half of the brain. It is one of the brain's busiest hubs. It helps you replay memories as vivid scenes, picture yourself in other places, and think about yourself. It is a core part of the default mode network, which lights up when your mind wanders.

Where it is

On the inner face of the parietal lobe, where the two halves of the brain face each other. It lies in front of the cuneus and above the posterior cingulate. You can only see it when the brain is split down the middle.

What it does

Replaying memories

It helps bring back personal memories as rich mental pictures, like the scene of your last birthday.

Mental imagery

It is busy when you imagine things, from picturing a route home to imagining a move in sports.

Sense of self

It helps you take a first-person view and reflect on yourself, your traits and your situation.

Mind wandering

As a hub of the default mode network, it is most active when you rest and let your thoughts drift.

Think of it as your mind's home cinema, where you replay memories and try out imagined scenes from your own point of view.

Works with

Posterior cingulate cortexIts close neighbor and partner at the center of the default mode network.
HippocampusThe hippocampus retrieves memories, and the precuneus helps turn them into vivid scenes.
Angular gyrus regionAnother default mode hub on the outer surface that works with it during daydreaming and recall.
Superior parietal lobuleThey share maps of space and body, which helps with imagining movements.
Prefrontal cortexThe front of the brain joins it when you think about yourself and plan for the future.

When it goes wrong

Early Alzheimer's disease

In Alzheimer's disease, the precuneus and posterior cingulate use less energy than normal, a pattern that helps doctors tell it apart from other dementias. Sticky amyloid protein also builds up here.

Loss of awareness

Its activity drops in sleep, under general anesthesia and in some disorders of consciousness, so some scientists think it helps support conscious awareness.

For learning only, not medical advice. If you have a health concern, talk to a doctor.

Surprising facts

The inner back part of the brain, including the precuneus, uses more energy than almost any other part of the cortex while you rest.
Because it is hidden deep between the hemispheres and damage rarely hits it alone, it long received little attention from scientists.

Where the name comes from

From the Latin "prae" (in front of) and "cuneus" (wedge). It is the region in front of the wedge-shaped cuneus.

Learn it in a lesson

The hidden cortexInsula, cingulate and the inner surfaces. A short guided lesson in 3D.

Quick quiz

3 questions. Your answers are saved and come back in your daily review.

Which of these is a job of the precuneus?
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Replaying memories. It helps bring back personal memories as rich mental pictures, like the scene of your last birthday.
The precuneus is part of which larger structure?
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Parietal lobe. It belongs to the parietal lobe.
Which part fits this description? "Like your mind's home cinema, where you replay memories and try out imagined scenes from your own point of view."
Show the answer
Precuneus. It is the precuneus. The brain's hidden inner eye for memories, imagination and your sense of self.

Sources

Precuneus, Radiopaedia
How is Attention Implemented in the Brain?, OpenStax, Introduction to Behavioral Neuroscience
Memory is Classified Based on Time Course and Type of Information Stored, OpenStax, Introduction to Behavioral Neuroscience

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