Lecture 35/36: Problem solving 2+3 Flashcards
What is a likely cause of most cortical lesions and what mix of symptoms can these cause
Stroke in branches of the anterior, middle and posterior cerebral arteries- cause a mix of symptoms - possible not to have all of them, depending on the branch
- Ant: Lower body Spastic paralysis, touch, pressure, proprioception loss, maybe pain+ temp
- Middle:
Upper body + lower face spastic paralysis, touch, pressure, proprioception loss.
-1’ auditory area: deafness
Left side:
- Writing and Reading comprehension/formulation: agraphia/dyslexia
- Pre motor areas: Broca’s for speech - nonfluent aphasia, Exner’s for writing
- Wernickes speech understanding: fluent aphasia.
- Post:
- 1’ Visual cortex: blindness in opposite visual field
Where do pain and temperature fibres sit in the cortex
Diffusely throughout the frontal lobe
Why is only lower face muscles lost when there is a lesion in the motor cortex
There are separate neurons for the upper facial and lower facial muscles from the motor cortex.
Both go from the motor cortex of one side to the CN7 facial nucleus of the other, synapsing in the upper half for upper facial muscles and lower half for lower facial muscles.
However, the neuron for upper facial muscles also has a collateral that innervates the facial nucleus from the same side as the motor cortex. Therefore if the lesion stops innervation to the face muscle from the other side, it will still be innervated by its own side and won’t be lost
What are the 5 subdivisions of the Internal capsule, what do they contain and what symptoms can lesions in these areas cause
All effects on the opposite side of the capsule
1. Anterior limb: fibres going to and from cortex to basal ganglia
- Genu:
Corticonuclear fibres - motor cortex fibres to CN nuclei (3,4,6,7,12) in the brainstem.
- leads to loss of motor innervation of head and neck. - Posterior limb:
Corticospinal fibres: 2 bundles, upper limb fibres anteriorly, lower limb fibres posteriorly.
- lead to paralysis of upper and lower limbs
Around this is sensory fibres from the VP-nuc. of thalamus ->cortex.
- Loss of Pain + temp
- Touch + pressure
- Retrolenticular- visual radiation
Fibres from the lat. geniculate body to 1’ visual cortex
-loss of all information from visual field from both eyes - homonymous hemianopia. - Sublenticular auditory radiation.
Fibres going under lenticular nuc. from medial geniculate body to 1’ auditory cortex.
- Loss of all hearing information- deafness
Which arteries supply the internal capsule
Branches of the Middle + Anterior cerebral artery branches (and internal carotid)
How can you differentiate between a lesion that affects the spinal cord and one that affects the brainstem/internal capsule/cortex
- A lesion in the spinal cord will not affect any face, head or neck muscles.
- There will also not be any precise band if sensory loss (dermatomal) from a brainstem/int capsule/ cortex lesion, only a spinal one.
- Dissociative sensory loss is a spinal cord lesions work whereas associated can be from brainstem/int capsule/cortex
If the left hemisphere is dominant for language functions in right handed people (left handed people, sometimes a mix) what is the right hemisphere associated with
- emotional nonverbal aspect of speech
- singing, which can be used to help repair left side damage
What is an example of cause for lesion developing between 4-6hrs, -12hrs, 1-2 weeks.
4-6hr: embolic and ischaemic onset leading to stroke
12 hr: expanding haemorrhage
1-2 week: tumour
What are some extra parts of the cortex that can be affected by the lesion but are unable to show clear signs
Frontal lobe (maybe personality change?), temporal gyrus.
How many segments of grey matter have to be affected before a small amount of pain and temperature loss can be felt on the same side as the lesion
More than 1 segment of grey matter. One segment can remain undetected.
