#8. Cerebellum, Diencephalon, Cerebrum, limbic system Flashcards
Why does the cerebellum have a highly folded surface?
increases the surface area of its outer grey matter, allowing for a greater number of neurons
How much of the brain mass is the cerebellum?
1/10
What separates the cerebellum from the cerebrum?
the tentorium cerebelli and the transverse fissure
What is the vermis?
the constricted central part (the worm)
Do the cerebellar hemispheres have lobes?
yes. the lobes are separated by deep and distinct fissures.
What does the anterior lobe of the cerebellum do?
governs subconscious movement of skeletal muscles
What does the posterior lobe of the cerebellum do?
governs the subconscious movement of skeletal muscles
What are the names of the cerebellar lobes?
anterior lobe, posterior lobe and the flocculonodular lobe
What is the flocculonodular lobe involved in?
equilibrium
What is the cerebellar cortex?
- superficial layer of the cortex
- consists of grey matter in a series of folia
What is folia?
it is grey matter in the cerebellar cortex that looks like leaves on a tree
What is arbor vitae?
it is white matter in the cerebellar cortex that looks like tree branches.
“tree of life”
Where are the cerebellar nuclei?
in the white matter
What do the cerebellar peduncles do and what are they made of?
the attach the cerebellum to the brain stem and they are bundles of white matter tracts
What is in the superior cerebellar peduncles?
axons that extend from the cerebellum to the red nuclei of the midbrain and to several nuclei of the thalamus
Describe the middle cerebellar peduncles
- largest
- axons carry impulses for voluntary movements from pontine nucleus to the cerebellum
What are the 5 different types of axons in the inferior cerebellar peduncles?
- axons of spinocerebellar tracts that carry sensory information from proprioceptors in the trunk and limbs
- axons from vestibular apparatus of inner ear and from vestibular nuclei of medulla and pons. Carry sensory info from proprioceptors in head
- axons from the inferior olivary nucelus of medulla and enter cerebellum and regulate cerebellar neurons
- axons that extend from the cerebellum to the vestibular nuclei of medulla and pons
- axons that extend from cerebellum to reticular formation
What are the functions of the cerebellum?
- primary function of cerebellum is to evaluate how well mvmts initiated by the cerebrum are actually carried out
- if not carried out correctly, the cerebellum detects the discrepancy and sends feedback signals to the cerebral cortex
- the feedback signals help correct the errors, smooth the mvmts and coordinate complex sequences of skeletal mm contractions
- also regulates posture and balance
- very active in learning new skills
What is ataxia?
loss of ability to coordinate mm mvmts.
What are some signs of ataxia?
- changed speech pattern due to uncoordinated speech mm
- staggering or abnormal walking gait
What can cause ataxia?
defenerative diseases (MS, Parkinson’s), trauma, brain tumours, genetic factors, meds side effects, and alcohol
What is the primary purpose of the thalamus?
to relay almost all sensory input to the cerebral cortex.
What is the thalamus made of?
paired oval masses of grey matter organized into nuclei with interspersed tracts of white matter.
What is the intermediate mass?
- variable connection b/w the 2 thalamic masses across the third ventricle
- 70% of people have it.
What is the intermediate mass also called?
the interthalamic adhesion
What is the internal medullary lamina?
- layers of myelinated fibers that appear on transverse sections of the thalamus
- Y-shaped white matter that splits each thalamus
What is the internal capsule?
- axons that connect the thalamus and cerebral cortex pass through it.
- a thick band of white mater lateral to the thalamus
- mostly motor axons
What are the major groups of nuclei on each side of the thalamus?
- anterior nucleus
- medial nuclei
- lateral group
- ventral group (5 nuclei)
- intralaminar nuclei
- midline nucleus
- reticular nucleus
What does the anterior nucleus of the thalamus do?
receives input from the hypothalamus and sends output to the limbic system
What does the anterior nucleus of the thalamus function in?
it functions in emotions and memory
What does the medial nuclei of the thalamus do?
receives input from the limbic system and basal nuclei and send output to the cerebral cortex
What does the medial nuclei of the thalamus function in?
it functions in emotions, learning, memory, and cognition (thinking and knowledge)
What does the lateral group of nuclei of the thalamus do?
receives input from the limbic system, superior colliculi and the cerebral cortex and sends output to the cerebral cortex
What does the lateral group of nuclei of the thalamus function in?
it functions in the expression of emotions.
What are the 5 nuclei in the ventral group of the thalamus?
- ventral anterior nucleus
- ventral lateral nucleus
- ventral posterior nucleus
- lateral geniculate nucleus
- medial geniculate nucleus
What does the ventral anterior nucleus of the thalamus do?
- receives input from the basal nuclei and sends output to the motor areas of the cerebral cortex
- plays a role in movement control
What does the ventral lateral nucleus of the thalamus do?
- receives input from the cerebellum and basal nuclei and sends output to motor areas of the cerebral cortex
- plays a tole in movement control
What does the ventral posterior nucleus of the thalamus do?
-relays impulses for somatic sensations such as touch, pressure, vibration, itch, tickle, temperature, pain and proprioception from the face and body to the cerebral cortex
What does the lateral geniculate nucleus of the thalamus do?
relays visual impulses for sight from the retina to the primary visual area of the cerebral cortex
What does the medial geniculate nucleus of the thalamsus do?
relays auditory impulses for hearing from the ear to the primary auditory area of the cerebral cortex