Unit 14: The brain and the basal ganglia Flashcards
What anatomical components are important in the lateral sulcus of the brain?
Superior sinus of the temporal lobe - auditory cortex
Deep to the lateral sulcus - the insula - gustatory and sensorimotor functioning.
What seperates the parietal and the occpital lobe?
The parieto-occipital sulcus
What sulcus is important for identifying the primary visual cortex?
Calcarine sulcus
What meningeal structure seperates the left and right cerebellum?
The falx cerebelli
What are the different ways the cerebellum can be separated?
Left and right by vermis (superior and inferior part)
The primary fissure - divided into the anterior and posterior lobe
The horizontal lobe - divided posterior into the inferior and superior lobe
What structure can be found on the inferior surface of the cerebellum?
The tonsil (note can be displaced through foramen magnum)
What structures are found on the ventral surface of the cerebellum? (Aka facing the brainstem)
The nodule - continuation of the inferior vermis
The flocculus
Together form the flocculonodular lobe (functional lobe)
What is the cerebellar folia?
Appearance of cerebellum - leaf-like.
Grey matter around outside and also in channels within, surrounded by white matter which extends within as channels (tree branches)
Describe the location of the cerebellar arteries in relation to the basilar artery
Superior cerebellar - branch from basilar before becomes posterior cerebral
Anterior infer - just before basilar runs over pons
Posterior inferior - just before unification of vertebral to form basilar
What do the different cerebellar arteries supply?
Superior - superior portion of anterior lobe
Ant inf - flocculus, sup posterior lobe, and potentially inferior posterior lobe
Post inf - inferior vermis and inferior position of the posterior lobe.
What is the basic function of the cerebellum?
Involved in motor control on the unconscious level.
Mainly influences action of the ipsilateral side
What is the vestibulocerebellum and what is its function?
Flocculonodular lobe/vermis
1. balance and control
2 posture
3. Gaze control
What is the spinocerebellum and what is its function?
Made from the vermis, paravermis and the anterior lobe
1. posture
2. Monotr and correct motor activity
3. coordination
What is the cerebrocerebellum and what is its function?
The lateral hemispheres
1. coordination
2, motor learning
3. Initiation of movement
What are the three different functional division of the cerebellum?
Vestibulocerebellum
Spinocerebellum
Cerebrocerebellar
What are the signs and functions of cerebellar dysfunction?
DANISH
Dysdiochokinesia - inability to perform rapid alternating movements
Ataxia - coordination
Nystagum - r,r,i eye
Intention tremor
Slurred speech
Hypotonia
What structures are associated with the ventricles?
The caudate nucleus
The thalamus
Where is CSF producted?
Choroid plexus - invagination of vascular pia matter into roof of lateral 3rd and 4th ventricles
What is the diaphragm sella?
Forms a dural roof over the pituitary gland
Where is the cavernous sinus located?
What does it drain into?
Bilateral plexus of drain
Found lateral to the sella turcia
Drains into the sigmoidal sinus via the superior petrosal sinus
Or into the internal jugular vein via the inferior petrosal sinus
What is the great cerebral vein?
What is its function?
Deep vein of the cerebrum
Other deep veins drain into it.
In combines with the inferior sagittal sinus to drain into the straight sinus.
What are the tributaries for the greater cerebral vein?
The internal cerebral veins (Left and right) - thalamus and choroid plexus of 3rd and lateral ventricles
Basal veins - midbrain structures.
These are the deep cerebral veins.
How can the superficial cerebral veins be classified?
Superior cerebral vein
Superficial middle cerebral vein
Both are present on the left and the right.
What is the role of the superior cerebral vein?
Travels superiorly up the lateral brain to drain into the superior sagittal sinus
What is the drainage route of the superficial cerebral vein?
Travels along the lateral fissure
1. Drain into superior sagittal sinus via a superior anastomotic vein
2. Drains into the transverse sinus via an inferior anastomotic vein
3. Extends internally into the cavernous sinus.
How do the basal ganglia affect movement?
Indirectly via regulating the activity of the thalamus and the primary motor cortex.
Via a balance of activity between the indirect and direct pathway.
What is the direct pathway of the basal ganglia?
The cerebral cortex and have glumatinergic projections to activate the striatum.
The striatum has GABAerigc projections to inhibit the GP internal and the SN pars reticulata.
Therefore reducing inhibitory GABAerigc projections from the GP internal and the SN pars reticulata to the thalamus
This enables the thalamus to communicate with M1 to initiate movement.
What is the indirect pathway of the basal ganglia?
- The cerebral cortex has glutaminergic projections to activate the subthalamic nucleus
- The cerebral cortex glutaminergic projections active the straitum, which has GABAerig projections into the GP external, this reduced GABAerig inhibition of the subthalamic nucleus via the GP external
The activate subthalamic nucleus has glutaminergic projections to the GP internal and SN pars reticularis.
These have GABAergic projections to inhibit the thalamus, prevent communication with M1, this inhibits unwanted movements.