ascending tracts

what is a first order/primary neuron?

what is a first order/primary neuron?

first neuron in line to get information from receptors in dorsal root ganglion

what is a second order/secondary neuron?

form the ascending tract carrying the sensory information up into the specific subcortical brain areas

what is a third order neuron?

carries information from subcortical areas to the cerebral cortex (primary sensory area)

what does the dorsal column- medial lemniscus pathway (DCML) sense?

conscious proprioception- discriminative/fine touch, pressure and kinesthesia

which receptors does the sensory information for the DCML come from

proprioceptors and mechanoreceptors

what does the first order neuron do in the DCML?

brings in sensory information to the dorsal root ganglion of the spinal cord and ascend up through the ipsilateral dorsal column

• axons from the lower body are medial and go up the fasciculus gracilis

• axons from the upper body are lateral and go up the fasciculus cuneatus

what does the secondary neuron do in the DCML?

brings both the funiculus gracilis and cuneatus will synapse in the either the nucleus gracilis or nucleus cuneatus respectively

where does the DCML decussate?

in the medulla, then they ascend up to the thalamus

what does the third order neuron do in the DCML?

travel from the thalamus to S1 and S2(post central gyrus/primary sensory area) via the internal capsule

what does the lateral spinothalamic tract respond to

conscious fast and discriminative pain as well as temperature in noicoreceptors and thermoreceptors

what does the first order neuron do in the LST?

information from the receptor is sent to the dorsal root ganglia

what does the second order neuron do in the LST?

information takes no pit stops and enters the SC via the dorsal root and synapses back n the dorsal horn

where does decussation occur in the LST?

in the SC before reaching the brainstem

where does the LST merge with the DCML?

in the pons of the brainstem

what does the third order neuron do in the LST?

synapses in ventral posterior lateral nucleus of the thalamus and ascend up to the central gyrus via the internal capsule

what does the Anterior spinothalamic tract sense?

transmits crude non-discriminative touch and pressure from mechanoreceptors

what does the first order neuron in the AST do?

information from the receptor is sent to the dorsal root ganglia

what does the second order neuron of the AST do?

information takes no pit stops and enters the SC via the dorsal root and synapses back n the dorsal horn

where does the AST decussate

in the SC before reaching the brainstem

where do the Lateral and anterior spinothalamic tracts merge?

medulla of the brainstem

what does the third order neuron of the AST do?

synapses in ventral posterior lateral nucleus of the thalamus and ascend up to the central gyrus via the internal capsule

what does the spinoreticular tract do?

through the reticular formation of the brainstem, it controls arousal to noxious and painful stimuli

what does the spinotectal tract do?

through the tectum of the midbrain it directs and orients our visual attention towards painful stimuli

what does the spino-emotional tract do?

through the cingulate gyrus it impacts emotional changes and responses to pain

what do the 4 spino-cerebellar tracts do?

involved with non-conscious proprioception and reflexes from proprioceptors, since they are not going to the cortex

what does the cuneocerebellar tract do?

carries proprioceptive information from the upper half of the body like neck UE and upper trunk

what does the posterior/dorsal spinocerebellar tract do?

carries proprioceptive info from the lower half of the body like T6 down

what does the rostral spinocerebellar tract do?

unconscious reflex circuits from the T1 and above on the body

what does the anterior/ventral spinocerebellar tract do?

unconscious information on reflex circuits from T2 and below