where is the embryological origin of the cerebrum?
telencephalon
where is the primary motor area located?
precentral gyrus in the frontal lobe
what is located in the inferior frontal gyrus?
broca’s area - important for language production
what happens if broca’s area is damaged?
expressive dysphasia (the patient can comprehend words but produces faulty sentences and phonemic errors) eg parket vs carpet
where is the postecentral gyrus located? and what does it contain?
parietal lobe
contains the primary soamtosensory area
damage to which area causes nominal aphasia?
inferior parietal lobule
what is nominal aphasia?
problems recalling words, name and numbers
what is in the superior temporal gyrus?
the auditory area of the cortex and Wernicke’s speech area in the dominant hemisphere (left)
what does damage to Wernick’es area cause?
receptive dysphasia - impaired comprehension but speech is fluent
what does the limbic system do?
emotional functions and memory system
which important structures are located in the limbic?
cingulate gyrus and hippocampus
where embryologically does the cerebellum come from?
metencephalon
which structure separates the cerebrum from the cerebellum?
tentori cerebelli
which 3 components is the cerebellum divided into?
vestibulocerebellum
spinocerebellum
cerebrocerebellum
what does the vestibulocerebellum do?
recieves input fro the vestibular organs for the maintanence of balance and coordinating vestibule ocular reflexes
what does the spinocerebelum do?
maintains muscle tone and participates in posture and gait
what does the cerebrocerebellum do?
coordination of voluntary motor activity and correct any error in the movements to ensure they are smoothly executed
which mneumonic is used to rememer the symptoms produced by cerebellar dysfunction?
DANISH
d - dysdiadochokineasia = impairment of rapid alternating movements (ask patient to perform quick, alternating pronation and supination of the hand)
a - ataxia (broa-based gait)
n - nystagmus (carry out the H test for extraoccular muscle function)
i - intention tremor (ask patient to do the finger-nose test)
s - scanning dysarthria - patient speaks slowly with poor articulation of speech
h - hypotonia - reduced tone
which structures come from the diencephalon?
thalamus, hypothalamus, subthalamus, epothalamus
which 3 systems does the hypothalamus influence?
- autonomic nervous system
- endocrine system
- limbic system
which symptoms arise from lesions to the subthalamic nuclei?
contralateral hemiballism - flinging movements of the upper and lower limbs on 1 side of the body
which are the main diseases affected by lesions to the basal ganglia and surrounding structures?
parkinson’s and huntington’s
a tumour / lesion/ stroke in the frontal lobe will present with which symptoms?
- contralateral weakness due to deficit in the primary motor cortex
- personality changes including disinhibition and cognitive slowing
- urinary incontinence
- gaze abnormalities
- expressive dysphasia / aphasia for left sided lesions if Broca’s area is involved
- seizures
a tumour / lesion / stroke in the temporal lobe will present with which symptoms?
- memory deficits
- receptive aphasia / dysphasia for left sided lesions if Wernikie’s area is involved
- contralateral superior quadrantopia
- seizures
a tumour / lesion / stroke in the parietal lobe will present with which symptoms?
- contralateral weakness and sensory loss due to deficit in the primary somatosensory cortex
- contralateral inferior quadrantopia
- dyscalculi (difficulty understanding maths), dysgraphia (unable to write), finger agnosia (unable to distinguish fingers) and left-right disorientation (confusion between right and left limbs) if dominant lobe is affected - GERSTMANN SYNDROME
- neglect (deficit in awareness of one side of the body), dressing apraxia and constructional apraxia - if nondominant lobe affected
a tumour / lesion / stroke in the occipital lobe will present with which symptoms?
- contalateral homonymous hemianopia
- visual hallucinations
a tumour / lesion / stroke in the cerebellum will present with which symptoms ?
- ipsilateral ataxia
- nausea and vomiting
- dizziness and vertigo
- slurred speech
- intention tremor
what is the WHO grading?
I - no morphological features
II - atypia alone
III - atypia and mitosis
IV - atypia and mitosis with vascular proliferation or necrosis
what are the most common primary brain tumours?
- high grade glioma (grade III eg anaplastic astrocytoma) or IV eg glioblastoma multiforme)
who gets glioblastoma multiforme?
60-70 year olds
what do glioblastomas look like on MRI?
butterfly appearance
what are the most common low grade gliomas?
pilocytic astrocytomas (grade 1) and diffuse astrocytoma or oligodendrogliomas (WHO grade II)
who gets pilocytic astrocytomas?
children and young adults
what is the appearance of pilocytic astrocytomas?
bipolar cells with long hair-like projections
what is the most common site for pilocytic astrocytomas?
cerebellum and midline stuctures eg thalamus or optic chaism
in which condition are optic pathway gliomas seen in ?
NF1
what are diffuse astrocytes (grade II)?
- have the potential to transform to high grade gliomas
- slow growing
- seizures
what is an oligodendroglioma?
- best prognosis
- frontal lobe of cerebral hemisphere
- can invade the subarachnoid space leading to a white toothpaste appearance
- seizures + headaches
what is a meningioma?
- originate from the arachnoidal cap cells within the arachnoid membrane
- common in elderly
- high risk in patients with NF2
- headahce
what is an acoustic neuroma?
- benign tumour derived from schwann cells
- arise in cerebellopontine angle
- if bilateral and young - NF2
what is a haemangioblastoma?
- benign, cystic, highly vascular tumours
- develop in posterior fossa, leading to cerebellar dysfunction symptoms and raised ICP
- associated with hippel landau syndrome