Functional Regions of the Brain Flashcards
Brown Sequard Syndrome is a condition of what type?
Dissociated Sensory Loss
Ascending Pathways are how many neuron pathways?
3 neuron pathways
In the ascending pathways, state where the three neurons go?
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
Descending Pathways are how many neuron pathways?
2 neuron pathways
In the descending pathways, state where the two neurons go?
1st neuron, from cerebrum / brain stem to spinal cord
2nd neuron, to the effector
The sulci are what?
The grooves of the brain
The gyri are what?
The folds surrounding the sulci
What is the equivalent of gyri in the cerebellum?
Folia
What is the central sulcus also known as? Where is it found?
Sulcus of Rolando, found across the superior aspect of the brain running coronally
What lobes of the brain are located anterior and posterior to the central sulcus?
Anteriorly: Frontal lobe
Posteriorly: Parietal lobe
What sulcus seperates the Parietal and Occipital lobe?
Parieto-Occipito sulcus
What sulcus seperates the Temporal lobes from the Frontal / Parietal lobes?
Lateral sulcus
The gyrus located in front of the central sulcus is called?
Precentral gyrus
The gyrus located behind the central sulcus is called?
Post central gyrus
The precentral gyrus forms which cortex?
Primary motor cortex
The postcentral gyrus forms which cortex?
Primary somato-sensory cortex
Describe what is meant by the body being somatotropically arranged in the brain?
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
Give the name for a descending tract(s) (motor)
Corticospinal tract
Give the name for the ascending tract(s) (sensory)
DCML
Spinothalamic tract
What is the Corticospinal tract responsible for?
Axial and limb motor control
Where does the Corticospinal tract begin?
Precentral gyrus
Outline the events of the Corticospinal tract in detail
- The corticospinal tracts begins with two neurones; one which will enervate the axial muscles and one enervating the limb muscles
- They leave the cortex by descending through the internal capsule and into the brain stem
- 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.
- 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.
- 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.
- 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.
The fibres of the Corticospinal tract which decussate at the medulla supply what?
The limbs
The fibres of the Corticospinal tract which don’t decussate at the medulla supply what?
Axial skeleton
The fibres of the Corticospinal tract which don’t decussate at the medulla follow which tract?
Anterior corticospinal tract
The fibres of the Corticospinal tract which decussate at the medulla follow which tract?
Lateral corticospinal tract
What is the corticobulbar tract?
Follows the same pathway as the Corticospinal tract, but remains in the brain stem and not travel down the spinal cord
What is the structure between the two hemispheres of the cerebellum?
Vermis
Cerebellar lesions lead to symptoms on which side?
The same side (ipsilateral) the lesion is on
Cerebral lesions lead to symptoms on which side?
The opposite (contralateral) side the lesion is on (usually)