Neuroanatomy and Neurophysiology Flashcards
What are the main constituent portions of the cerebral cortex and give a brief description of their asscoaited functions?
Frontal lobe: executive function, motor cortex and speech and language on the dominant side (Broca’s area).
Parietal: Somatosensory including spatial awareness.
Temporal: olfaction, auditory capabilities, memory and emotional functioning. Language capabilities Wernecke’s area is on the superior surface on the dominant hemisphere.
Occipital: Visual functioning.
Draw and label the circle of willis and it’s branches?
List the cranial nerve nuclei in each constituent part of the brainstem?
Originate from the brainstem:
Medulla oblongata, Pons, Midbrain
CN I-IV originate above the Pons:
- CN I + II are above the midbrain
- CN III + IV are in the midbrain.
CN V-VIII orignate in the Pons
CN IX-XII originate in the Medulla
Think rule of 4’s
Describe the syndrome that would arise from a lesion in the cerebral hemisphere?
Focal neurology depending on which region of the cerebral hemisphere is affected.
Prefrontal area: dysexecutive function.
Temporoparietal cortex: agnosia (inability to recognise)
Language centers: aphasia’s (broca’s = broken speech)(wenicke = unable to understand)
Bilateral temporal lobes: amnesia
Premotor cortex: will result in apraxia (inability to execute motor function despite normal strength)
Describe the syndrome that would arise from a lesion in the brainstem?
Different syndromes depending on the exact location of the insult:
If it damaged the cerebellar communicants and the motor fibres it could cause: ipsilateral cerebellar signs and contralateral UMN pyrimidal weakness (effects extensors more)
Respiratory centre is in the medulla and therefore if there is damage here it can affect respiration.
Reticular formation running through the brainstem is responsible for cardiorespiratory control, sleep, balance and conjugate eye movements. Rarely can also cause locked in syndrome
Many of the cranial nn run arise in the brainstem therefore an insult could cause specific cranial nn palsies.
Describe the syndrome that would arise from a syndrome in the cerebellum?
Lesions are ipsilateral and they cause problems with coordination:
DANISH
Dysdiadokinesis
Cerebellar ataxia
Nystagmus
Intention tremor
Slurred speech/scanning dysarthria
Hypotonia
Describe the syndrome that would arise from a syndrome in basal ganglia?
Unilateral lesions affect the contralateral side.
Pathology causes loss of control of volunatary posture and control with changes in muscular tone.
Parkinsons causes the following symptoms: TRAP
Tremor
Rigidity (hypertonia)
Akinesia*
Postural instability (shuffling gait)
Also causes the patient to have a blank expression
* (loss or impairment of the power of voluntary movement)
Huntington’s presents with basal ganglia signs of:
Chorea a type of dyskinesia (involuntary movements)
In Tourettes syndrome presents with involuntary tics.
Outline the visual pathway?
Optic nn
Optic Chaism
Optic tract (superior and inferior fibres together)
Lateral Geniculate nucleus
Optic Radiations
Visual cortex (Travels to the occipital lobe broadman’s area 17. )
What are the different places in the visual tract that can be affected and what lesions do they cause?
Name the location of the causative lesion in homonymous hemianopia?
Optic tract lesion.
If it is a left sided homomynous hemianopia then the lesion will be in the right optic tract.
Can’t see out the left as lesion is on the right posterior tract.
Name the location of the causative lesion in bitemporal hemianopia?
Optic Chiasm
Name the location of the causative lesion in a homoynous quadrantanopia?
The optic radiations of the geniculocalcarine tract.
If the visual loss is on the left then the lesion is on the right.
PITS - Parietal Inferior, Temporal Superior
If it is in the upper visual field it is from the superior retinal fibres running through the Temporal lobe.
If it is in the lower visual field the lesion is from the inferior retinal fibres running through the Parietal lobe.
So if you have a left inferior homomynous hemianopia then the lesion will be in right parietal retinal fibres of the geniculocalcarine tract.
If the lesion was a right sided superior homomynous hemianopia then the lseion would be in the left temporal lobe retinal fibres of the geniculocalcarine tract.
Name the location of the causative lesion in monocular visual field loss?
Optic nn lesion of the affected eye.
Describe the location of broca and wernicke’s area and their function?
Only foud in the dominant hemisphere
Broca’s: broadmann area 44 in the frontal lobe
Wernicke’s: broadmann area 22 in the temporal lobe
Broca’s area: is involved in speech production and comprehension.
Wernicke’s area: is predominantly involved in speech comprehension.
Describe the types of aphasia when there is dysfunction of broca or wernicke’s area?
Dysfunction in Broca’s area is associated with expressive apahsia were there is relatively good speech comprehension however there is difficulty in speech production therefore the speech becomes broken, synactic and gramatically incorrect.
E.g “Drive, store. Mom.” meaning to say, “My mom drove me to the store today”.
Dysfunction with Wernicke’s area is assocaited with receptive aphasia in this condition patients can speak fluently however they cannot comprehend therefore what they are saying is a word salad.
Draw and label a cross section of the spinal cord and label the spinothalamic pathways, the corticospinal tracts and the dorsal column?
Describe the clinical syndrome that would arise from cord hemisection? (transecting half the cord)
Brown-Séquard syndrome
On the ipsilateral paralysis and loss of proprioception on the same side as the injury or lesion
Contralateral loss of pain and temperature sensation
Bilateral ataxia may also occur if the ventral spinocerebellar tract and dorsal spinocerebellar tract are affected.
