Cerebellum Flashcards
What are the major organizational divisions of the cerebellum?
- Cerebellar cortex
- Dentate nucleus of cerebellum
The cerebellum is functionally divided into vermis, medial hemisphere and lateral hemisphere
What is the origin of mossy fibers?
inputs into the middle, inferior and superior cerebellar peduncles; much more plentiful than mossy.
What is the origin of climbing fibers?
Originate from the inferior olivary nucleus (medulla)
What is the wiring diagram?
1 climbing will wrap around to excite an purkinje. (increase its inhibitory effect)
Mossy fibers synapse on granule cells which together form parallel fibers that will synpase on purkinje cells; thus less of an inhibitory effect than climbing.
Important to modulate how active the purkinje cell can get (thus its inhibitory effect on the deep cerebellar nuclei)
you can end up with an active zone and a zone of inhibition.
What are the functional components of the cerebellum?
Important for coordination: correction of current movements to match those intended.
- monitoring system, analyzes the motor activity and uses the info as feedback to the cortex to adjust movements so that what you are doing is what you want to do.
- receives a lot of unconscious activity
Describe the somatotopic map of the cerebellum.
Middle portion of the cerebellum controls stability, trunk.
Hemisphere controls more limbs and distal part of extremities.
Localized structures that have relation to one another have close proximity.
How do inputs/afferent information enter the cerebellum?
Inputs occur from different sensory systems, through axons such as mossy fibers and climbing fibers.
These axons enter through: Inferior and middle cerebellar peduncles. (1 exception, anterior spinocerebellar tract enters through the superior cerebellar peduncle)
What are some inputs into the cerebellum?
Sensory inputs via spinocerebellar + other tracts
Cerebrocerebellar pathway through the pontine nuclei
A lesion with the cerebellum or basal ganglion causes what types of symptoms:
Since they are not directly linked up to motor/anterior horn cells, they will not show muscle weakness but do have motor difficulty.
What are the major outputs of the cerebellum?
To motor systems:
- Thalamus
- Vestibular nuclei
- Reticular formaiton
NO direct connection to the spinal cord
How does output/efferent information leave the cerebellum?
Through purkinje cells, are inhibitory cells that project to deep cerebellar nuclei. From there, the deep cerebellar nuclei project out.
These projects exit mainly through the superior cerebellar peduncle. (1 exception)
Main projects from the deep cerebellar nuclei:
Thalamus, Vestibular Nuclei,
Red nucleus
How is the brainstem connected to the cerebellum?
Through cerebellar peduncles.
- Inferior and middle are info IN.
- Superior is info OUT
exception
Anterior Spinocerebellar tract ENTERS through the SUPERIOR.
The primary fissure divides the cerebellum into…
Anterior lobe and posterior lobe
What are purkinje cells and what’s their role in the cerebellum?
Are the only axons that leave the cerebellar cortex. Inhibitory on deep cerebellar nuclei.
1 cell layer thick
high amount of dendrite
1 climbing fiber/1 purkinje
1 mossy synapses on a granule cell which then join other granule cells to become parallel cells which then synapse on purkinje.
Dendrites in the molecular layer
What are the three layers of the cerebellum?
- Molecular (mainly axons and dendrite, basket cells and stellate cells that synpase on purkinje)
- Purkinje cell layer
- Granular layer
