Touch Pathways

dorsal column medial lemniscus/DCML

__________ ________ _________ _________ pathway: sensory info from the body (not face), including:
⇒light discriminative touch
⇒pressure
⇒vibration
⇒proprioception

light discriminative

DCML pathway: sensory info from the body (not face), including:
⇒___________ ___________ touch
⇒pressure
⇒vibration
⇒proprioception

pressure

DCML pathway: sensory info from the body (not face), including:
⇒light discriminative touch
⇒________________
⇒vibration
⇒proprioception

vibration

DCML pathway: sensory info from the body (not face), including:
⇒light discriminative touch
⇒pressure
⇒___________
⇒proprioception

proprioception

DCML pathway: sensory info from the body (not face), including:
⇒light discriminative touch
⇒pressure
⇒vibration
⇒_________________

body

DCML pathway transmits info from the *body/face/both*

high

DCML pathway receptors have a *high/low* number of sensory units

small

DCML pathway receptors have *large/small* receptive field

better

DCML pathway receptors have *better/worse* localization

high

DCML pathway receptors have a *high/low* degree of sensation in fingers and mouth

c

which type(s) of receptors are NOT a part of the DCML pathway?
a. pacinian corpuscles
b. meissner's corpuscles
c. free nerve endings
d. merkel's discs
e. ruffini endings
f. GTOs
g. muscle spindles
h. joint receptors
i. ligament receptors
j. all of the above receptors use the DCML pathway

3

somatosensory information proceeds from a receptor through a ___-neuron pathway

first

the ________ order neuron in the DCML pathway is peripheral receptor to brainstem

brainstem

first order neuron in DCML pathway goes from peripheral receptor to ____________

receptor

first order neuron in DCML pathway goes from peripheral _________ to brainstem

brainstem

second order neuron in DCML pathway goes from ____________ to thalamus

thalamus

second order neuron in DCML pathway goes from brainstem to ____________

second

_____________ order neuron in DCML pathway goes from brainstem to thalamus

third

__________ order neuron in DCML pathway goes from thalamus to cerebral hemispheres

thalamus

third order neuron in DCML pathway goes from _________ to cerebral hemispheres

cerebral hemispheres

third order neuron in DCML pathway goes from thalamus to __________ __________

projection neurons

neurons with long axons that connect distant regions of the nervous system

dorsal root ganglion/DRG

location of cell body of first order neuron in DCML pathway

first

_________ order neuron cell body for DCML pathway is located in the DRG

second

__________ order neuron cell body for DCML pathway is located in nucleus cuneatus or gracilis

nucleus cuneatus

second order neuron cell body in DCML pathway for upper extremity is located in the __________ _________

nucleus gracilis

second order neuron cell body in DCML pathway for lower extremity is located in the _____ ______

VPL

third order neuron cell body for DCML pathway is located in the ________ of the thalamus

thalamus

third order neuron cell body for DCML pathway is located in the VPL of the _____________

third

_________ order neuron cell body for DCML pathway is located in the VPL of the thalamus

T7

first order neuron in DCML pathway ascends in fasciculus gracilis if below ______ or fasciculus cuneatus above this level

first

the _________ order neuron of the DCML pathway ascends in the fasciculus gracilis (below T7) or cuneatus (above T7)

lower medulla

first order neuron of DCML pathway synapses in nucleus gracilis or cuneatus in the ___________ ____________

second

the ___________ order neuron of the DCML pathway crosses as internal arcuate fibers

internal arcuate fibers

fibers of second order neuron in DCML pathway cross midline as _________ _________ ___________

contralateral

second order neuron of DCML ascends in *ipsilateral/contralateral* medial lemniscus

medial lemniscus

second order neuron of DCML ascends in contralateral _____________ ______________

second

_______________ order neuron of DCML ascends in contralateral medial lemniscus

posterior

third order neuron of DCML passes through the __________ limb of internal capsule and projects to primary somatosensory cortex post central gyrus

third

DCML _________ order neuron projects to primary somatosensory cortex post central gyrus

post

primary somatosensory cortex is *pre/post* central gyrus

leg trunk arm face

what is the somatotopic organization of the somatosensory cortex? rank the following from most medial to most lateral: face, trunk, arm, and leg

cortex

for a sensory stimulus to reach consciousness, the signal needs to reach the ____________

thalamus

crude awareness of a sensory stimulus may be possible if the signal reaches the ____________, but a meaningful awareness and any ability to discriminate the stimulus requires that the signal reaches the cortex

discriminative

DCML is a conscious relay pathway that is "____________" (ability to localize the sensation); high fidelity

high

DCML is a *high/low* fidelity pathway

high fidelity

provides accurate information about the location of stimulation; a somatotopic map is crated

somatotopic

______________ map; aka homonculus; allows high fidelity/discrimination of accurate location of sensation

isilateral

DCML pathway ascends through the *ipsilateral/contralateral* spinal cord*

lower medulla

DCML pathway crosses in the __________ ____________

parietal

DCML pathway is perceived in the __________ lobe

legs

fasciculus gracilis is associated with *arms/legs*

arms

fasciculus cuneatus is associated with *arms/legs*

ipsilateral

if a sensory pathway is cut before it crosses, signs and symptoms will be *ipsilateral/contralateral* to the lesion

contralateral

if a sensory pathway is cut after it crosses, signs & symptoms will be *ipsilateral/contralateral* to the lesion

d

trigeminothalamic pathway *does not* carry which of the following from the face?
a. light discriminative touch
b. pressure
c. vibration
d. proprioception
e. it carries all of the above

d

the main sensory nucleus/trigeminal lemniscus portion of the trigeminothalamic pathway carries all of the following from the face *EXCEPT*:
a. light discriminative touch
b. pressure
c. vibration
d. proprioception
e. it carries all of the above

medulla

the dorsal column medial lemniscus pathway carries light discriminative touch, pressure, vibration, and proprioception from the body (i.e. caudal to the _________________)

trigeminothalamic

the ______________ pathway carries light discriminative touch, pressure, and vibration (main sensory nucleus/trigeminal lemniscus), as well as proprioception (mesencephalic nucleus/reticular formation) from the face

face

trigeminothalamic pathway carries light discriminative touch, pressure, and vibration from the *body/face/both*

mesencephalic nucleus

the __________ ___________/reticular formation portion of the trigeminothalamic pathway carries proprioception from the face

reticular formation

the mesencephalic nucleus/_________ ________ portion of the trigeminothalamic pathway carries proprioception from the face

proprioception

the mesencephalic nucleus/reticular formation portion of the trigeminothalamic pathway carries _____________ from the face

main sensory nucleus

the ___________ __________ ____________/trigeminal lemniscus portion of the trigeminothalamic pathway carries light discriminative touch, pressure, and vibration from the face

trigeminal lemniscus

the main sensory nucleus/____________ ___________ portion of the trigeminothalamic pathway carries light discriminative touch, pressure, and vibration from the face

first

the ________ order neuron of the trigeminothalamic pathway for discriminative touch has a receptor from face, cell body in trigeminal ganglion, and synapses in main sensory nucleus of CN V (in the pons)

receptor

the first order neuron of the trigeminothalamic pathway for discriminative touch has a ____________ from face, cell body in trigeminal ganglion, and synapses in main sensory nucleus of CN V (in the pons)

trigeminal ganglion

the first order neuron of the trigeminothalamic pathway for discriminative touch has a receptor from face, cell body in _________ ___________, and synapses in main sensory nucleus of CN V (in the pons)

main sensory nucleus

the first order neuron of the trigeminothalamic pathway for discriminative touch has a receptor from face, cell body in trigeminal ganglion, and synapses in ________ ________ __________ of CN V (in the pons)

pons

the first order neuron of the trigeminothalamic pathway for discriminative touch has a receptor from face, cell body in trigeminal ganglion, and synapses in main sensory nucleus of CN V (in the ________)

second

the __________ order neuron of the trigeminothalamic pathway for discriminative touch:
⇒cell body in main sensory nucleus of CN V
⇒cross midline in pons
⇒ascends in contralateral trigeminal lemniscus
⇒synapse in VPM in the thalamus

VPM

the *VPL/VPM* of the thalamus receives info from the face

VPL

the *VPL/VPM* of the thalamus receives info from the body

main sensory nucleus

the second order neuron of the trigeminothalamic pathway for discriminative touch:
⇒cell body in _______ _________ ________ of CN V
⇒cross midline in pons
⇒ascends in contralateral trigeminal lemniscus
⇒synapse in VPM in the thalamus

pons

the second order neuron of the trigeminothalamic pathway for discriminative touch:
⇒cell body in main sensory nucleusof CN V
⇒cross midline in ________
⇒ascends in contralateral trigeminal lemniscus
⇒synapse in VPM in the thalamus

pons

the trigeminothalamic pathway will cross midline in the ________

second

the __________ order neuron of the trigeminothalamic pathway will cross midline

contralateral

the second order neuron of the trigeminothalamic pathway for discriminative touch:
⇒cell body in main sensory nucleusof CN V
⇒cross midline in pons
⇒ascends in *ipsilateral/contralateral* trigeminal lemniscus
⇒synapse in VPM in the thalamus

trigeminal lemniscus

the second order neuron of the trigeminothalamic pathway for discriminative touch:
⇒cell body in main sensory nucleusof CN V
⇒cross midline in pons
⇒ascends in contralateral __________ ___________
⇒synapse in VPM in the thalamus

VPM

the second order neuron of the trigeminothalamic pathway for discriminative touch:
⇒cell body in main sensory nucleusof CN V
⇒cross midline in pons
⇒ascends in contralateral trigeminal lemniscus
⇒synapse in _______ in the thalamus

third

the __________ order neuron in the trigeminothalamic pathway for discriminative touch:
⇒cell body in VPM of thalamus
⇒passes through posterior limb of internal capsule
⇒projects to primary somatosensory cortex post central gyrus (parietal lobe)

thalamus

the third order neuron in the trigeminothalamic pathway for discriminative touch:
⇒cell body in VPM of ____________
⇒passes through posterior limb of internal capsule
⇒projects to primary somatosensory cortex post central gyrus (parietal lobe)

internal capsule

the third order neuron in the trigeminothalamic pathway for discriminative touch:
⇒cell body in VPM of thalamus
⇒passes through posterior limb of ___________ ___________
⇒projects to primary somatosensory cortex post central gyrus (parietal lobe)

parietal

the third order neuron in the trigeminothalamic pathway for discriminative touch:
⇒cell body in VPM of thalamus
⇒passes through posterior limb of internal capsule
⇒projects to primary somatosensory cortex post central gyrus (_________ lobe)

ipsilateral lower body

a lesion of fasciculus gracilis will cause loss of *contralateral/ipsilateral* discriminative touch to *face/upper body/lower body*

ipsilateral

a lesion of the dorsal root of L4 would cause a *contralateral/ipsilateral* loss of discriminative touch to the medial leg & foot

b

a lesion to the bilateral fasciculus gracilis and fasciculus cuneatus at T4 will cause loss of discriminative touch to:
a. bilateral whole body
b. bilateral loss below T4
c. bilateral loss 1-2 levels below T4
d. bilateral loss to face

ipsilateral

a lesion of fasciculus gracilis at C7 will cause *ipsilataral/contralateral* loss of discriminative touch below T7

below T7

a lesion of fasciculus gracilis at the level of C7 will cause ipsilateral loss of discriminative touch *above/below* _____

ipsilateral whole body

a lesion of nucleus gracilis and nucleus cuneatus in the lower medulla would cause *ipsilateral/contralateral* loss of discriminative touch from *above T7/belowT7/whole body/body and face*

contralateral whole body

a lesion of the medial lemniscus would cause *ipsilateral/contralateral* loss of discriminative touch from *above T7/below T7/whole body/face*

ipsilateral face

a lesion of the main sensory nucleus of V would cause *ipsilateral/contralateral* loss of discriminative touch from *above T7/below T7/whole body/face*

contralateral body and face

a lesion of the medial lemniscus and trigeminal lemniscus in the upper midbrain would cause *ipsilateral/contralateral* loss of discriminative touch from *whole body/face/body and face*

contralateral

a lesion of the most medial part of the primary somatosensory cortex would cause *ipsilateral/contralateral* loss of discriminative touch from the foot and lower leg