CH16 Brainstem Tracts 1 Flashcards
What types of vertical tracts are in the brainstem?
- sensory
- autonomic
- motor
vertical tracts: synapses or no?
- Some tracts continue through the brainstem without alteration
- Brainstem acts as a conduit
The brainstem is divided longitudinally into two sections:
- basilar
- tegmentum
Describe and name the additional longitudinal brainstem section (aside from the basilar and tegmentum)
Where is it?
TECTUM
- in the midbrain
- posterior to the tegmentum
The tectum includes structures involved in reflexive control of:
- intrinsic and extrinsic eye muscles
- movements in the head
important parts of the tectum
- pretectal area
- superior and inferior colliculi
(I think?)
Where is the basilar section of the brainstem? What does it primarily contain?
- anterior
- mostly motor
Which motor structures does the basilar section contain?
- descending axons from cerebral cortex
- motor nuclei
- pontocerebellar axons
Which descending tracts are in the basilar section?
- CST
- corticobulbar
- corticopontine
- corticoreticular
Which motor nuclei are in the basilar section?
- SN
- pontine nuclei
- inferior olivary nucleus
What is included in the reticular formation?
complex network
- reticular nuclei (and their connections)
- ascending/descending reticular pathways
What does the reticular formation do?
- Integrates sensory and cortical information
- Regulates somatic motor activity, autonomic function, and consciousness.
- Modulates nociceptive (pain) information.
What are the major reticular nuclei?
- ventral tegmental area (VTA)
- pedunculopontine nucleus (PPN)
- raphe nuclei
- locus ceruleus & medial reticular area
Most neurons that produce dopamine are located here
midbrain
What are the two production areas of dopamine in the midbrain?
- VTA (part of reticular formation)
- SNpc
What happens when the VTA is activated?
produces feelings of pleasure and reward
What nucleus does the VTA affect?
nucleus accumbens
Why is morphine habit forming?
inhibits inhibitory inputs to the VTA
Where is the PPN located?
caudal midbrain
Where do ascending axons from the PPN project?
- to the inferior part of the frontal cerebral cortex
- intralaminar nuclei of the thalamus
Through which connections does the PPN influence movement?
- Globus pallidus and subthalamic nucleus
- Limbic system
- Reticular areas that give rise to reticulospinal tracts
What NT (NM) does the VTA use?
dopamine
What NT (NM) does the PPN use?
acetylcholine
What NT (NM) do the raphe nuclei use?
serotonin
