Cerebellum
Generally what is the Cellular http://quizlet.com/edit/567926/Organization of the Cerebellum ?
The cellular organization of the cerebellar cortex is highly regular. There is a molecular layer then a single layer of large Purkinje Cells . Then a layer of Granular Cells.
What are the three longitudinal divisions of the Cerebellum?
Vermis, Intermediate Zone, Lateral Hemisphere
what does the flocculonodular lobe do?
send vestibular nuclei - balance and eye movement.
what are the three types of inhibitory interneurons in the cerebellar cortex?
stellate, basket, golgi
majority of the output from the cerebellum is where?
vast majority of the output is from the superior cerebellar peduncle.
what types of deficits will patients with Parkinson's have?
wide-based gait. ataxia. intention tremor. rapid alternating movements.
the majority of the input to the cerebellum is where?
middle cerebellar peduncle.
What are the three aspects of Cerebellum Organization that underlies its function?
1. Cerebellum receives extensive info. about goals, commands, and feedback signals associated with programming and execution of movement. (40X more neurons enter than leave). 2. Most of the output from the cerebellum goes to motor and premotor cortex regions of cerebral cortex and brainstem. 3. Synaptic connections in cerebellar circuits are modifiable suggesting "learning" is occurring in the cerebellum.
what type of information does the Cerebellum receive?
BOTH sensory and motor information.
what are the two afferent fibers going to the Cerebellar Cortex?
Climbing fibers and Mossy fibers
What are the Deep Cerebellar Nuclei?
Don't Eat Greasy Food. Dentate Emboliform Globose Fastigial. The Emboliform and Globose make the Interposed.
where are the deep cerebellar nuclei located?
Fastigial - Vermis. Interposed - Intermediate Zone. Dentate - Lateral Hemisphere.
what is the main role of the Cerebellum?
INTEGRATE sensory and motor signaling to plan movements and to refine them once they have begun. To assess error between intended and actual movements and signal to the motor centers to make the necessary adjustments for precision.
What is the vascular supply of the cerebellum?
Superior Cerebellar Artery, AICA (Anterior Inferior Cerebellar Artery), PICA (Posterior Inferior Cerebellar Artery)
will lesions of the cerebellum cause sensory deficits?
NO. cerebellar lesions will affect the rate, force, and range of movements resulting in deficits in spatial accuracy and temporal coordination.
what are the cell types of the Cerebellum?
Purkinje cells - ONLY neurons that leave the cerebellar cortex (sole efferents), send out inhibitory signals via neurotransmitter GABA. Granule Cells - cerebellar interneurons whose cell bodies lie in the Granular layer. Each sends its axons into the Molecular layer, where it bisects into a fine Parallel fiber, which travels perpendicular to the plane of the Purkinje cells, synapsing onto the dendrites of a succession of up to 500 Purkinje cells.
how does information leave the cerebellum?
Purkinje fibers synapse onto cells bodies in the Deep Cerebellar Nuclei. Almost all output from the Cerebellum Travels Through the Deep Cerebellar Nuclei. Almost all Output Through the Cerebellum goes through the Deep Cerebellar Nuclei.
what is the spinocerebellum?
Spinocerebellum is the Vermis AND Intermediate Zone combined. Named so because they are the only parts of the cerebellum that receive somatosensory information from the spinal cord.
discuss the vestibulocerebellum.
cell bodies of neurons from the semicircular canals and otolith organs relay information on head motion and position relative to gravity to the vestibular nuclei. Mossy fiber cell bodies in the vestibular nuclei project axons to the flocculonodular lobe. Visual information is also sent from mossy fiber cell bodies in superior colliculi and from striate cortical cells via relay through the pontine nuclei. Output - Purkinje cells of the vestibulocerebellum send inhibitory signals to the vestibular nuclei to modulate the medial and lateral vestibulospinal tracts, which control trunk and limb muscles and regulate balance and gait. The output to the medial vestibular n. controls eye movements and head-eye movements coordination (via the MLF).
what is ataxia?
gross lack of coordination of muscle movements.
Mossy fibers
have cell bodies in the spinal cord and brain stem and carry sensory information from the body and cortex to the cerebellum. Their axons project to the granule cell layer where they synapse onto granule cell dendrites, which transmit an excitatory signal via their long Parallel fibers to excite the dendrites of large numbers of Purkinje cells. Each Purkinje cell receives input from up to 1 million granule cells, which each receives input from many mossy fibers. action potentials create simple spikes in Purkinje cell firing.
Climbing fibers
have cell codies in the inferior olivary nucleus and carry visual, somatosensory, cerebrocortical information. action potentials produce "complex spikes" in Purkinje cell firing.
where does corticopontine input go to?
lateral hemisphere and flocculonodular.
Lateral Hemisphere (Input, Output, Function)
receives input solely from the cortex and therefore called the Cerebrocerebellum. It send output via the dentate nucleus to motor, premotor, and prefrontal cortices. Its roles are to plan and mentally rehearse complex motor actions and conscious assessment of movement errors.
Intermediate Zone (Input, Output, Function)
receives somatosensory information from the limbs. It projects, via the interposed nuclei, to the corticospinal and rubrospinal systems to control distal muscles of the limbs and the digits.
Vermis (Input, Output, Function)
receives visual, auditory, & vestibular input and some somatic input from the head and proximal body. It sends output via the fastigial nucleus to cortical and brainstem regions that then give rise to the medial descending motor system, to control proximal body and limb muscles. This region regulates posture, locomotion and gaze.
