Glossary
Reticular Formation
What is the reticular formation?
The reticular formation is a network of neurons and clusters of neurons, called nuclei, spread through the brainstem. Its connections help regulate alertness, sleep, movement, posture, automatic bodily functions, and responses to sensory information.
Anatomy and connections
The network extends through the midbrain, pons, and medulla. Ascending connections reach regions including the thalamus and cerebral cortex; descending reticulospinal pathways reach the spinal cord. Different parts have different jobs, so this is not one neatly bounded structure with a single purpose.
Functions of the reticular formation
- Alertness: ascending arousal systems help maintain wakefulness and responsiveness.
- Posture and movement: reticulospinal connections influence muscle tone and coordination.
- Sensory responses: neurons integrate inputs from different senses, and these systems contribute to changes in responses to repeated stimulation.
Several transmitter systems participate. For example, raphe nuclei use serotonin, while cholinergic cells use acetylcholine. A transmitter name alone does not identify a single function; each acts through particular connections and receptors.
What happens when the reticular formation is damaged?
Damage to these brainstem systems can affect consciousness, movement, or automatic bodily functions. Studying them helps researchers understand how the brain keeps us awake and responsive.
How researchers study it
Researchers examine its anatomy, electrical activity, imaging, and the effects of injury. Its spread-out structure makes individual parts hard to isolate. Scalp EEG can track brain activity associated with alertness, but it cannot record the reticular formation selectively.