- Yawning is coordinated from brainstem sites
near the paraventricular nucleus via
extrapyramidal pathways.
- This reflex may occur in patients "locked
in" from pontine transection who have
nonvolitional mouth opening
- with spontaneous yawns.
- Yawning in the setting of a pyramidal
lesion (capsular infarction) may be
associated with arm stretchling in the paretic
limb, supporting the involvement of extra
pyramidal circuitry.
- Cortical input also occurs, as reflected by
the yawning related to boredom
and somnolence. Yawning has been seen to
initiate a temporal lobe
seizure.
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