Week 1 - D - Neuroanatomy 3 - Basal ganglia and cerebellum Flashcards
The three oval objects all have arrows that come from the same structure, it just changes position as we ascend through the brainstem What is this structure? What is the arrow going to in the midbrain?
This is the medial lemniscus The arrow going to the midbrain shows the cerebral aqueduct
What sensation does the dorsal column / medial lemniscus tract provide? What sensation does the spinothalamic tract provide? (which ones are by the lateral and which by the anterior spinothalamic tracts) What tract provides fine precise movement and supplies axial and limb muscles?
DCML - fine touch, vibration and proprioception Spinothalamic - deep pressure, temperature and pain Deep pressure - anterior Temperature/pain - Lateral Corticospinal tract is the desceding pathway supplying these movements
What would an infarct in the intenal capsule result in for the corticsopinal tract? Internal capsule is where the axons travel in the cerebral hemispheres
This would result in spastic paralysis with hyperflexion of the limbs
Lateral hemisection of the spinal cord is also known as Brown-Sequard syndrome Explain the features of Brown-Sequard syndrome? ie if there was a right hemisection of the spinal cord
There would be ipsilateral loss of fine touch, vibration and proprioception sensation - DCML There would be contralateral loss of deep pressure, temperature and pain - Spinothalamic tract There would be ipsilateral paralysis and ipsilateral hyperfelxia
Generally the frontal cortex is very much involved in motor control very much further then just the precentral gyrus if there is an intended movement planned in the precentral gyrus (primary motor cortex), what 2 parts of the brain and what tract carries out the action?
The basal ganglia and the cerebellum are informed of the action The corticospinal tract delivers the information to the muscles to carry out the action
When the sensory fibres return with information regarding the movement, where do these fibres return the information before it reaches the thalmus?
The sensory information regarding the movement is returned to the cerebellum before the thalamus
The cerebellum is largely a movement computer – also has functions of motor memory What two functions does the cerebellum mainly control?
Mainly controls movement and coordination
What are the three lobes of the cerebellum?
The anterior lobe, posterior lobe and flocculonodular lobe
Where is the flocculus of the flocculonodular lobe located?
It is located at the ponto-medullary junction of the brainstem The 2 floccus is on the outer parts and the nodulus is in the centre of the lobe
Why is the cerebellum described as subtentorial?
This is because it lies beneath the tentorium cerebelli
The cerebellum like the crerbral hemispheres has a core of white matter with a outside grey matter (there are some grey matter structure deep in the cerebellum however) At what level of the brainstem is the white matter entering the cerebellum? what sits between this level and the cerebellum?
Enters at the level of the pons Will find the fourth ventricle and between the cerebellum and the pons here
the cerebellum is attached to the brainstem via three peduncles What are these peduncles known as? Which is by far the biggest?
Known as the superior cerebellar peduncle, the middle cerebellar peduncle and inferior cerebellar peduncle The middle cerebellar peduncle is by far the biggest
Which lobe lies anterior to the primary fissure of the cerebellum and which lies posterior to it?
The anterior lobe lies anterior to primary fissure Posterior lobe lies posteriorly
If we took the cerebellum, cut it off at the three peduncles and flattened it What would the area of gyri that is pinched together be known as? What fissure exists between the flocculonodular lobe and the posterior lobe?
This area would be known as the vermis The posterolateral fissure exists between the flocculonodular and posterior lobes
What is the cerbellar white matter known as? (tree of life)
It is known as the arbor vitae
If we slice of the top of the cerebellum we are able to locate the deep grey matter structures of the cerebellum How many deep grey matter structures are there on each side of the cerebellum? What is the largeest deep grey matter structure known as?
There are 4 deep grey matter structures on each side of the cerebellum with the largest known as the dentate nucleus
The cerebellar cortex is divided into 3 layers What are these three layers?
These are the Molecular layer Purkinje layer Granular layer
Important afferents arrive to the cerebellum via cerebellar peduncles and project mainly to which layer of the cerebral cortex?
They project mainly to the granular layer of the cerebral cortex
From all three lobes of the cerebellum: the only output is via the axons of which cells? Where do the axons of these cells synapse?
The only output is via the purkinje cells of the cerebral cortex and their axons synapse on the deep cerebellar nuclei
Most efferent axons of deep cerebellar nuclei cross the midline Where do the axons then synapse before travelling to the motor cortex?
The axons synapse in the thalamus before travelling to the primary motor cortex
The cerebellum has functional divisions as it is split into hemispheres Do cerebellar hemispheres influence the ipsi or contralateral side of the body? Also - posterior fissure is meant to be posterolateral in pic
Cerebellar hemispheres influence the ipsilateral side of the body
Bilateral cerebellar dysfunction results in what symptoms?(Acute alcohol exposure typically results in bilateral cerebellar hemisphere dysfunction and presents with cerebellar ataxia. - think of symptoms when drunk)
Bilateral cerebellar dysfunction can result in slowed speech and incoordinated gait / wide based gait (cerebellar ataxia)
What separates the globus pallidus and the thalamus? Where is the body of the caudate nucleus found in relation to the lentiform nucleus?
They are separated by the internal capsule (the huge strip of white matter It is found superomedially
The basal ganglia is found relatively near the base of cerebral hemispheres Can see on axial slice What structure of the basal ganglia will you be able to see if looking at the lateral wall of the lateral ventricle?
Will be able to see the caudate nucleus as it follows the same pathway as the lateral ventricle
Where is the substantia nigra found and what colour is it? What chronic disease is it lost in?
Substantia nigra is found in the midbrain and is black It is lost in Parkinson’s disease
Label the arrows from top to bottom
Caudate nucleus Thalamus Putamen Lateral globus pallidus Medial globus pallidus Subthalamc nucleus Substantia nigra
Label all the different colour of circle
Purple - head of caudate nucleus Black - body of caudate nucleus green - thalamus Blue - tail of caudate nucleus Pink - amygdala Silver - golubus pallidus Orange - putamen
Label the diagram
Black - the lateral ventricle Silver - caudate nucleus Brown - internal capsule Red - putamen Yellow - medial and lateral globus pallidus Blue - thalamus Purple - insular lobe
