Cerebellum Flashcards
What are the motor functions of vermis? non-motor?
motor- balance, eye movements, reflexes
nonmotor- autonomic arousal, limbic regulation
What are the motor functions of paravermis? nonmotor?
motor- sensorimotor integration, movement execution
nonmotor- simple verbal response to commands
What are the motor functions of lateral hemisphere (includes dentate nucleus)? nonmotor?
motor- prep and planning of eye movements, fine motor dexterity, imagined movements
nonmotor- verbal association, rule-based learning, working memory, problem solving, monitoring performance, temporal perception
What are the names for these regions- vermis, floculus/nodulus, lateral hemisphere- based on source of strongest input?
vermis- spinocerebellum
flocculus/nodulus- vestibulocerebellum
lateral- cerebrocerebellum
What are the 3 basic elements that compose the cerebellum?
cerebellar cortex, deep cerebellar nuclei, large white matter tracts
What are the 6 neuron types in cerebellar cortex?
granule, golgi, purkinje, stellate, basket, lugaro
What are the 2 neurons in deep cerebellar nuclei?
projection neurons, interneurons
What are the 3 layers of cerebellar cortex?
molecular layer, Purkinje cell layer, granule cell layer
What do Purkinje cells project to? Is it inhibitory or excitatory synapse?
deep output nuclei, inhibitory
What synapses on granule cells? Say where they are from and whether it is excitatory or inhibitory.
mossy fibers from pontine nuclei- excitatory
mossy fibers from RF, vestibular nuclei, spinal cord- excitatory
NE, DA, 5HT, ACh- excitatory
golgi cells- inhibitory
What synapses on Purkinje cells?
climbing fibers from inferior olive- excitatory
parallel fibers from granule cells- excitatory
What does the deep output nuclei project to? (3) tell whether excitatory or inhibitory.
VA/VL of thalamus- excitatory
inferior olive- inhibitory
red nucleus magnocellular path (rubrospinal tract)
What projects to the deep output nuclei?
purkinje cell- inhibitory
inferior olive- excitatory
Trace the path from purkinje cells to cortex.
Purkinje cell inhibits deep nuclei, which powerfully activate the thalamus and motor cortex
What are the AP types for purkinje cells?
simple spike and complex spike
What input to Purkinje cells cause simple spikes? Describe simple spikes.
parallel fibers from granule cell, predictable APs in response to specific aspects of movement
What do simple spikes reflect?
moment to moment changes in behavior
What is the efference copy?
copy of commands for movement
What is the reafference copy?
expected sensory info coming back from body part being used
Where does the dorsal spinocerebellar tract arise from and what info does it carry?
from clarke’s nucleus, carries reafference info from lower limbs
Where does the ventral spinocerebellar tract arise from and what info does it carry?
from the ventral horn, efference copy for lower limbs
Where does the cuneocerebellar tract arise from and what info does it carry?
from the accessory cuneate nucleus, carries reafferance info from upper limbs
Where does the rostral spinocerebellar tract arise from and what info does it carry?
from the ventral horn, efference copy for the upper limbs
What input to Purkinje cells causes complex spikes? Describe complex spikes.
climbing fibers from inferior olive, single AP in IO causes long lasting purkinje cell depolarization resulting in 5 APs and causes Purkinje cell to be refractory to parallel fiber activation during it and in afterhyperpolariation after it occurs
What does the complex spike reflect?
occurence of unexpected stimuli/errors
-it is possible to modulate a reflex with an error signal to turn it off, case of rapid learning
What does a lateral cerebellar lesion cause?
asthenia, atonia, ataxia, dysmetria, intention tremor, asynergia, decomposition of movement, dysdiadochokinesia
What is asynergia?
difficulty coordinating muscle actions
What is decomposition of movement?
normal complex movements broken down into single movements around a joint
What exogenous substance can produce similar effects to lateral cerebellar lesion?
alcohol
What is scanning speech?
articulation is problematic, have stacatto, decomposed sentences
Does the cerebellum have somatotopy?
yes, has fractured somatotopy connected by horizontal parallel fibers
Is information organized somatotopically in the VL thalamus from the deep output nuclei?
yes
Where is the cerebellar microexcitatory zone? What does pacemaking this treat?
in the thalamus, treats essential tremor
How does the cerebellum cause adaptive modification of behavior?
through error signals, it can modify commands for movements to optimize outcome (can do it for nonmotor too)
Does the cerebellum contribute to language and cognitive function? If yes, what proves it?
yes, there are reciprocal interconnections to the frontal lobe
-retrograde transneuronal transport of HSV1 showed connections from cerebellum to prefrontal cortex via thalamus
What output nucleus and area of the cerebellum is active in the insanely difficult task?
dentate, lateral cerebellum
area is very involved in complex processing
What nonmotor deficits happen with a PICA lesion due to cerebellum deficits?
failure in rule-based language tasks, failure in error detection and practice related improvement
What is an essential tremor caused by?
excess activity at inferior olive, causes complex spikes of purkinje so they go refractory which promotes deep nuclei output, also has direct connection to deep nuclei output to excite it
How can you distinguish essential tremor from parkinsons?
alcohol/barbituates stop it
-alcohol acts as glu antagonist/gaba agonist at deep nuclei to dampen output to decrease thalamic output to cortex
How can you treat essential tremor?
thalamtomy, deep brain stimulation of VPL thalamus to pacemake it in the microexcitatory zone
Do lesions in the cerebellum cause a loss of function?
no, they cause impairments in quality of movement and other functions
