What are the 3 types of general sensory systems we have discussed?
Epicritic Sensibility (fine touch/vibration)
Protopathic Sensibility (pain/heat)
Where do sensory neurons of proprioceptive sensibility from the lower half of the body above L4 synapse in the spinal cord?
on multipolar neurons in the Clark-Stilling (Dorsal) Nucleus (T9 - L3)
What spinal cord white matter does proprioceptive information travel through after leaving the Clark-Stilling nucleus?
enters the lateral funiculus of the same side and ascends in the dorsal spinocerebellar (Flechsig) tract
Through what structure does the dorsal spinocerebellar tract finally reach the cerebellum?
And which part of the cerebellum?
through the Inferior Cerebellar Peduncle
to the Paleocerebellum
Where do sensory neurons of proprioceptive sensibility from the lower half of the body below L3 synapse in the spinal cord?
in the intermediate zone and ventral horn
What is the path of proprioceptive information from below L3 after its synapse in the spinal grey matter?
it decussates in the anterior white commissure, then...
ascends via the Ventral Spinocerebellar Tract (of Gowers) in the Lateral Funiculus
What is the pathway for proprioceptive sensation from below L3 once it is in the brain?
after traveling through the ventral spinocerebellar (Gower's) tract...
...crosses again in the superior medullary velum, then...
...enters the spinocerebellum via the superior cereberellar peduncle
What is the pathway in the spinal cord for proprioceptive sensation from the upper body?
(Burdach's) Cuneate Fascicle
an uncrossed pathway in the dorsal funiculus
Once in the brainstem, where does proprioceptive sensation from the upper body synapse first?
in the accessory/external cuneate nucleus (just lateral to cuneate nucleus)
How does proprioceptive sensation originating from the upper half of the body get from the brainstem to its final destination?
after leaving the accessory cuneate nucleus...
it courses through the cuneocerebellar tract in the inferior cerebellar peduncle
How is epicritic information first sensed?
via Meissner's Corpuscles in dermal CT papillae
Where does epicritic information from the lower half of the body travel in the spinal cord?
Gracile Fascicle (of Goll)
in the dorsal funiculus on the same side as the stimulation
Where does epicritic information from the upper half of the body travel in the spinal cord?
Burdach's Cuneate Fascicle
- in the dorsal funiculus on the same side as the stimulation
Once epicritic information has reached the medullary nuclei (gracile/cuneate), what happens to its fibers (still within the medulla)?
they cross as the internal arcuate fibers forming the lemniscal decussation
Where does epicritic information go from the medulla and how does it get there?
it travels to the thalamus VPL via the medial lemniscus
Where does epicritic sensation travel from the thalamus?
since it is sensory information...
it goes to the Post-central Gyrus...
via the Internal Capsule
Where does protopathic information from the body go after entering the spinal grey matter?
it decussates via the anterior white commissure and ascends in the spinothalamic tract
Where are the 2nd order neurons conveying protopathic information from the body found?
Depending on the type of protopathic sensation, information will travel in different parts of the spinothalamic tract.
What type travels in which part?
Anterior Spinothalamic = crude touch, pressure
Lateral Spinothalamic = heat, pain
To where does protopathic information from the body travel via its spinal cord tract?
the spinothalamic tract takes protopathic information the the Thalamus VPL
Where does protopathic information go from the thalamus?
thalamus VPL > post-central gyrus
In what structure does the first neuron carrying epicritic sensation from the head have its perikaryon?
And where is it?
in the Trigeminal Ganglion (of Gasser)
found in Meckel's Cave
Where is the perikaryon of the second neuron carrying epicritic information from the head?
Pontine/Principle Trigeminal Nucleus
What course does epicritic sensation from the head take from its 2nd neuron in the principle trigeminal nucleus?
it decussates and ascends in the trigeminal lemniscus
(Agota said "dorsal trigeminal lemniscus" but the handout seems to say otherwise on pg. 43)
Where the 2nd order neuron carrying epicritic information from the head synapse?
Where does the first neuron carrying protopathic information from the head have its perikaryon?
Where does the 2nd neuron carrying protopathic information from the head have its perikaryon?
in the spinal trigeminal nucleus
located in the lateral portion of the medulla
Where does protopathic sensation from the head go after it has left the medulla?
it decussates and ascends via the spinal trigeminal lemniscus
To what part of the thalamus does protopathic information from the head go?
it goes to the Thalamus VPM via the spinal trigeminal lemniscus