Major Spinal Cord Tracts

What type of sensory information does the dorsal white column (DCML) carry?

Vibration, two-point discrimination, deep touch, visceral pain, and proprioception

Where is the 1st-order neuron located? DCML

Dorsal Root Ganglion

What are the tracts of the 1st-order neurons? DCML

• Fasciculus gracilis → Lower body

• Fasciculus cuneatus → Upper body

Where is the 2nd-order neurons located? DCML

In the nucleus gracilis and nucleus cuneatus

What do 2nd-order neurons become after crossing over? DCML

The medial lemniscus

Where is the 3rd-order neuron located? DCML

In the thalamus

Where does the 3rd-order neuron project to? DCML

The primary sensory cortex

Which side of the brain processes sensory input from the right body?

The left side of the brain

What type of sensory information does the spinothalamic tract carry?

Pain, temperature, light touch, pressure, itch, and tickle

Where is the 1st-order neuron located? (Spinothalamic)

Dorsal root ganglion

Where is the 2nd-order neurons located? (Spinothalamic)

Dorsal horn

How does the 2nd order neuron cross over? (Spinothalamic)

Lateral Spinothalamic Tract

Where is the 3rd-order neuron located?

in the thalamus

Where do 3rd-order neurons project to?

The primary sensory cortex (postcentral gyrus)

What is the function of the lateral corticospinal tract?

Controls voluntary motor movement of skeletal muscles

Where is the 1st-order neuron located? (Lateral Corticospinal)

Primary motor cortex (precentral gyrus)

What special map is found in the precentral gyrus?

The motor homunculus (shows which body parts are controlled where)

Where is the 2nd-order neuron located? (Lateral Corticospinal)

Ventral Horn

What do the 2nd-order neurons synapse with in the ventral horn?

Interneurons and lower motor neurons

What is the terminal target of the lateral corticospinal tract?

Skeletal muscle

Is the lateral corticospinal tract sensory or motor?

Motor