Functional Regions of the Brain

Question 1

Brown Sequard Syndrome is a condition of what type?

Answer 1

Dissociated Sensory Loss

Question 2

Ascending Pathways are how many neuron pathways?

Answer 2

3 neuron pathways

Question 3

In the ascending pathways, state where the three neurons go?

Answer 3

1st neuron, to the spinal cord / brainstem

2nd neuron, from the nucleus in the CNS to the thalamus

3rd neuron, from the thalamus to the cortex

Question 4

Descending Pathways are how many neuron pathways?

Answer 4

2 neuron pathways

Question 5

In the descending pathways, state where the two neurons go?

Answer 5

1st neuron, from cerebrum / brain stem to spinal cord

2nd neuron, to the effector

Question 6

The sulci are what?

Answer 6

The grooves of the brain

Question 7

The gyri are what?

Answer 7

The folds surrounding the sulci

Question 8

What is the equivalent of gyri in the cerebellum?

Answer 8

Folia

Question 9

What is the central sulcus also known as? Where is it found?

Answer 9

Sulcus of Rolando, found across the superior aspect of the brain running coronally

Question 10

What lobes of the brain are located anterior and posterior to the central sulcus?

Answer 10

Anteriorly: Frontal lobe
Posteriorly: Parietal lobe

Question 11

What sulcus seperates the Parietal and Occipital lobe?

Answer 11

Parieto-Occipito sulcus

Question 12

What sulcus seperates the Temporal lobes from the Frontal / Parietal lobes?

Answer 12

Lateral sulcus

Question 13

The gyrus located in front of the central sulcus is called?

Answer 13

Precentral gyrus

Question 14

The gyrus located behind the central sulcus is called?

Answer 14

Post central gyrus

Question 15

The precentral gyrus forms which cortex?

Answer 15

Primary motor cortex

Question 16

The postcentral gyrus forms which cortex?

Answer 16

Primary somato-sensory cortex

Question 17

Describe what is meant by the body being somatotropically arranged in the brain?

Answer 17

Both motor and sensory systems are somatotropically arranged. The face is located laterally, the trunk of the body over the top, the lower limbs over the mid-line of the brain

Question 18

Give the name for a descending tract(s) (motor)

Answer 18

Corticospinal tract

Question 19

Give the name for the ascending tract(s) (sensory)

Answer 19

DCML

Spinothalamic tract

Question 20

What is the Corticospinal tract responsible for?

Answer 20

Axial and limb motor control

Question 21

Where does the Corticospinal tract begin?

Answer 21

Precentral gyrus

Question 22

Outline the events of the Corticospinal tract in detail

Answer 22

1. The corticospinal tracts begins with two neurones; one which will enervate the axial muscles and one enervating the limb muscles
2. They leave the cortex by descending through the internal capsule and into the brain stem
3. As the pathway descends into the medulla, 75-90% of the fibres decussate (cross over) at the Decussation of Pyramids. The decussated fibres will enervate the limbs. The fibres which enervate the axial muscles do not decussate here.
4. After leaving the brain stem, the fibres descend down through the two corticospinal tracts in the spinal cord. The decussated fibres descend down the lateral corticospinal tract and the non-decussated fibres descending down the anterior corticospinal tract.
5. Upon finally reaching their target level, the fibres of the anterior cortical spinal tract finally decussate through the anterior white commissure, before synapsing to a neuron located in the anterior horn of the grey matter, called an anterior horn cell.
6. Conversely, the fibres of the lateral corticospinal tract have already decussated at the level of the pyramids. As such, upon reaching the appropriate level they just synapse onto a neuron in the anterior horn, also called an anterior horn cell.
   These anterior horn cells then project to the limb muscles and axial muscles.

Question 23

The fibres of the Corticospinal tract which decussate at the medulla supply what?

Answer 23

The limbs

Question 24

The fibres of the Corticospinal tract which don’t decussate at the medulla supply what?

Answer 24

Axial skeleton

Question 25

The fibres of the Corticospinal tract which don’t decussate at the medulla follow which tract?

Answer 25

Anterior corticospinal tract

Question 26

The fibres of the Corticospinal tract which decussate at the medulla follow which tract?

Answer 26

Lateral corticospinal tract

Question 27

What is the corticobulbar tract?

Answer 27

Follows the same pathway as the Corticospinal tract, but remains in the brain stem and not travel down the spinal cord

Question 28

What is the structure between the two hemispheres of the cerebellum?

Answer 28

Vermis

Question 29

Cerebellar lesions lead to symptoms on which side?

Answer 29

The same side (ipsilateral) the lesion is on

Question 30

Cerebral lesions lead to symptoms on which side?

Answer 30

The opposite (contralateral) side the lesion is on (usually)