Word
Reticular activating system
The brain's gatekeeper for attention: the brainstem network that keeps you awake and decides which of the signals reaching your senses are worth your awareness
Examples
Damage to the reticular activating system can cause coma, because the cortex is never switched on.
Your reticular activating system is why a parent sleeps through traffic but wakes at the baby's smallest cry.
Origin
From the Latin reticulum, “little net,” describing the mesh-like tangle of neurons, the reticular formation, in which the system sits. The word “activating” was added when researchers discovered the network's job was to switch the cortex on.
How it connects
The net of neurons that sets the volume on consciousness itself.
This word appeared in Attention is filtered before it is conscious, the Involves connection for August 28, 2026, which asked: Why do you suddenly notice a word everywhere the day after you learn it?
Check yourself
What is the reticular activating system's core job?
Regulating arousal and wakefulness, and gating which signals reach the alert cortex.. Right. The RAS controls the brain's overall level of arousal: the difference between asleep, drowsy, and alert.
What the sources establish
The reticular activating system regulates arousal and wakefulness and modulates the cortex's readiness to process incoming signals.
Sources
Reticular Formation (Encyclopaedia Britannica, 2024), Sections on the ascending reticular activating system and arousal