Ascending sensory pathways I Flashcards
What is spinothalamic responsible for?
Pain, temp, some touch and pressure
What is dorsal column pathway responsible for?
Touch, vibration and position
Three ways of knowing where we are in space
Vestibulocochlear system
Muscle spindles
Visual
Spinothalamic pathway have what type of fibres
Thin, poorly myelinated or unmyelinated fibres
Slow conduction
Dorsal column pathway have what type of pathways and why
Large diameter, heavily myelinated
Fast conduction
For higher perception e.g. 2-point discrimination and vibration and proprioception
Where is primary sensory cortex?
Post central gyrus
First order neuron for spinothalamic and dorsal column
DRG
Pseudounipolar cell body outside of CNS
Sensory receptor to CNS
Note does not synapse! just gives off cell body
Second order neuron for spinothalamic and dorsal column
Always synapses upon immediately entering the spinal cord - ipsilateral grey matter
These are the neurons that cross the midline but at different points
Third order neuron for spinothalamic and dorsal column
Thalamus - posterior ventral nucleus
Goes on to terminate at primary sensory cortex in post central gyrus
Dorsal column is…
Ipsilateral
Spinothalamic is…
Contralateral
Lateral corticospinal is…
Ipsilateral
Ventral corticospinal is…
Contralateral
Spinothalamic second order neuron crosses midline where
Ventral white commisure
Ventral to central to central canal
Past the medulla the spinothalamic tract becomes
The spinal lemniscus
Where does primary neuron run in dorsal column?
Primary neuron runs up the spinal cord to important nuclei of gracile and cuneate
Where does gracile fasicle run?
Whole length of spinal cord medially
graceful ballerina
Where does cuneate fascicle run?
Above T6 lateral
Where do the primary neurons of dorsal column pathway synapse?
SAME SIDE
Then decussate through internal arcuate fibres to form medial lemniscus which ascends contralateral brainstem to VPL
Dorsal column second neuron distribution in medial lemniscus from dorsal to ventral at closed medulla
Arm -> trunk -> leg
To clarify, arm is most dorsal
Second order neuron of dorsal column synapse where to become third
Posterior limb of internal capsule
Second order spinothalamic synapses where to become third
Post. limb of internal capsule
