Anatomy: Upper Pons
Midbrain
Bilateral thalamus
Bilateral frontal cortex
!NB - The reticular formation dose not include nuclei of CN or the long tracts that pass through the brain stem (dorsal column-medial lemniscus pathway, spinothalamic tract, corticospinal tract)
The reticular formation consist of:
1. Short interneurons in the spinal cord & brain stem that generate and coordinate stereotyped motor activity e.g. facial expressions, swallowing, breathing.
2. Interneurons in the thalamus that influence sensory perception and arousal
3. Long projection neurons with cell bodies in the brain stem & hypothalamus and their axons ascending to the forebrain or descending to the spinal cord.
Traditional division (based on clinical presentation):
Rostral components (at and above the pons) - lesions → Sx hypersomnia;
Caudal components (below pons) - lesions → Sx insomnia.
Relevant division - the nuclei r divided into 3 columns:
Median column - the raphe nuclei;
Medial column - the magnocellular nuclei;
Lateral column - the parvocellular nuclei.