Group

Deep brain structures

Also called Deep brain structures, Subcortical structures

The hidden machinery under the wrinkly surface that runs habits, senses and survival.

Open in 3D

The wrinkly outer layer of the brain, the cortex, gets most of the attention. But tucked underneath it is a whole hidden world of deep structures. These include the basal ganglia (which help pick your actions), the thalamus and hypothalamus (the sensory switchboard and the body's control center), the limbic system (memory and emotion), fluid-filled spaces called ventricles, and thick cables of white matter. Much of what keeps you alive, alert and feeling things happens down here, mostly without you noticing.

Where it is

Deep in the center of the brain, wrapped on all sides by the cortex and sitting on top of the brainstem.

What it does

Think of it as the engine room below the deck of a ship: passengers only see the deck, but the engines, wiring and control rooms below keep everything running.

Inside the deep parts of the brain

• Basal gangliaYour action selector: says "go" to one move and "no-go" to all the rest.
• DiencephalonThe "in-between brain": home of the thalamus, hypothalamus and a few tiny glands.
• Limbic systemThe brain's emotion and memory team, wrapped around its deep core.
• Ventricular systemA hidden network of fluid-filled chambers that cushions and cleans the brain.
• White matter pathwaysThe brain's wiring: bundles of fat-wrapped cables that let distant regions talk fast.

Works with

• Basal gangliaThe action selectors that decide "go" or "no-go" for every move you make.
• DiencephalonThe central core with the thalamus, hypothalamus and a few tiny glands.
• Limbic systemThe memory and emotion circuit that wraps around the deep core.
• Ventricular systemFluid-filled spaces that cushion the deep structures and carry away waste.
• White matter pathwaysThe cable network that links the deep parts to the cortex and to each other.
• BrainstemThe stalk below that connects all these deep parts to the spinal cord and body.

When it goes wrong

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

Surprising facts

• Nearly every sense you have, except smell, passes through the thalamus in the middle of your brain before you become aware of it.
• Your body makes roughly half a liter of brain fluid every day, so the fluid bathing your brain is replaced several times a day.
• More than 100,000 people with Parkinson's disease around the world have had thin wires placed deep in their brains to ease their symptoms.

Where the name comes from

"Subcortical", the scientific word for these parts, simply means "below the cortex". Cortex is Latin for "bark", like the bark wrapped around a tree.

Sources

1. 13.2 The Central Nervous System, OpenStax, Anatomy and Physiology 2e
2. Physiology, Cerebral Spinal Fluid, StatPearls, NCBI Bookshelf
3. Deep brain stimulation for Parkinson's disease, Lasker Foundation

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