RETICULAR FORMATION
- Reticular formation is a network consists of nerve cells (neurons) and nerve fibers (axons) scattered within dorsal part of the brainstem extending superiorly to the hypothalamus & thalamus and inferiorly to the spinal cord.
- The reticular formation can be divided into 3 columns: (in brainstem) median (raphe), medial and lateral zone
Medullary & pontine RF:
→ Afferent tracts:
- Spinal cord Paleospinothalamic tract →
- gigantocellular nuc. (medulla)
- caudal pontine reticular nucl.
- Fibers from CN sensory nucl. →
- paravocellular. Ret. nuc.
- oral pontine Ret. nuc.
- Cerebellum →
- lateral reticular n.
- paramedian reticular nucleus
- Cerebral cortex corticoreticular → RFN reticulospinal → spinal cord.
→ Efferent.
- Gigantocellular nu
- Caudal reticular nu
- Ascending → Cerebral Cortex
- Descending → Spinal cord.
Functions:
- The reticular formation, especially the reticular activating system (RAS) is essential for maintaining wakefulness and overall consciousness.
- Involved in the regulation of the sleep-wake cycle.
- Regulates autonomic functions such as heart rate, blood pressure, and respiratory rate.
- Crucial for motor control, including the regulation of muscle tone and regulation.
- Because its connection with limbic structures, may play role in emotional processing & expression.
- All afferent and efferent systems either relay in or give collaterals to the RF.
- Neurons of the RF project their axons in both rostral & caudal directions, can reach nearby or distant structures & conduct impulses rapidly or slowly.