Term
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Definition
| the external part of the cerebellum that is a thin, highly convoluted sheet of gray matter |
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Term
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Definition
| the transversely-arranged folds of the cerebellar cortex |
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Term
| The axons of what kinds of cells mediate all signaling out of the cerebellum? |
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Definition
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Term
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Definition
| masses of gray matter embedded in the white matter in the central parts of the cerebellum |
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Term
| Do subdivisions of the cerebellum based on functional differences correspond closely with subdivisions based on afferent connections? |
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Definition
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Term
| What is the most primitive part of the cerebellum (the part occurring first during phylogeny)? |
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Definition
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Term
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Definition
| the midline of the flocculonodular lobe |
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Term
| Why is the flocculonodular lobe also called the vestibulocerebellum? |
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Definition
| it receives afferents primarily from the vestibular apparatus & the vestibular nuclei |
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Term
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Definition
| the medialmost part of the cerebellar hemispheres that borders the vermis medially |
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Term
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Definition
| a deep, transversely oriented cleft that divides the corpus cerebelli |
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Term
| 2 lobes that the primary fissure divides the cerebellum into |
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Definition
1. anterior lobe (in front of the primary fissure)
2. posterior lobe (behind the primary fissure) |
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Term
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Definition
| the midportion of the vermis & the hemispheres; younger part of the cerebellum |
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Term
| Why are the anterior & posterior portions of the vermis & the adjoining parts of the intermediate zone of the corpus cerebelli also called the spinocerebellum? |
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Definition
| they receive afferents primarily from the spinal cord |
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Term
| Why are the hemispheres of the cerebellum also called the cerebrocerebellum or the pontocerebellum? |
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Definition
| they receive their main input from the cerebral cortex |
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Term
| Where do different parts of the cerebellum send their efferent connections? |
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Definition
| the three main subdivisions of the cerebellum act on the parts of the CNS from which they receive their afferents; the vestibulocerebellum sends fibers mainly to the vestibular nuclei; the spinocerebellum influences the spinal cord; the cerebrocerebellum acts on the cerebral cortex |
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Term
| primary vestibular afferents |
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Definition
| bring sensory signals from the vestibular apparatus in the inner ear |
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Term
| direct spinocerebellar tracts |
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Definition
| pathways that go uninterrupted from the cord to the cerebellum |
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Term
| Is there a group of direct spinocerebellar tracts that provides information about the level of activity among specific groups of spinal interneurons? |
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Definition
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Term
| Is there an indirect spinocerebellar tract that is synaptically interrupted in the inferior olive in the medulla? |
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Definition
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Term
| Where do spino-olivary fibers end? |
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Definition
| in parts of the inferior olive that project to the spinocerebellum of the opposite side (like the direct spinocerebellar tracts) |
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Term
| Are spinocerebellar pathways somatotopically organized? |
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Definition
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Term
| Where does the largest number of cerebellar afferent fibers arise from? |
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Definition
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Term
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Definition
| the afferents to the pontine nuclei that arise in the cerebral cortex |
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Term
| 2 places where most of the corticopontine fibers arise |
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Definition
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Term
| Are there substantial contributions to the corticopontine fibers from the supplementary motor cortex (SMA) & premotor cortex (PMA) & areas 5 & 7 of the posterior parietal cortex? |
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Definition
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Term
| Are there contributions to the corticopontine fibers from the prefrontal cortex? |
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Definition
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Term
| Do the pontine nuclei receive afferents from the visual cortex? |
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Definition
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Term
| What are connections from the visual cortex to the pontine nuclei important for? |
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Definition
| execution of visually guided movements |
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Term
| 2 main limbic structures the pontine nuclei receive connections from |
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Definition
1. mammillary bodies
2. cingulate gyrus |
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Term
| Is the corticopontine projection topographically organized? |
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Definition
| yes! different cortical regions project to largely different parts of the pontine nuclei |
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Term
| Do connections from the cerebral cortex to the pontine nuclei exhibit large or small divergence? |
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Definition
| large (a small part of cortex influences small clusters of neurons in widespread parts of the pontine nuclei) |
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Term
| Does the pontocerebellar tract show high or low convergence? |
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Definition
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Term
| Does the cerebellum compare copies of the motor commands sent from the cerebral cortex with the signals from the periphery providing information about the actual movement that was produced by the commands? |
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Definition
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Term
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Definition
| the middle layer of the cerebellum that is dominated by the large Purkinje cells arranged in a monolayer |
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Term
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Definition
| the deepest, lowermost layer of the cerebellum; packed with granule cells |
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Term
| What direction to parallel fibers run in? |
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Definition
| the direction of the long axis of the folia |
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Term
| 2 reasons why the Purkinje cell dendritic tree is unusual |
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Definition
1. it has an enormously rich branching pattern
2. the dendritic tree is compressed into one plane |
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Term
| What do inhibitory interneurons in the cerebellar cortex do? |
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Definition
| limit the activity of the Purkinje cells & increase the spatial precision of the incoming signals |
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Term
| What neurotransmitter do Purkinje cells contain? |
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Definition
| gamma-aminobutyric acid (GABA); they inhibit their target cells |
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Term
| What neurotransmitter do granule cells contain? |
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Definition
| glutamate; they have an excitatory action on the Purkinje cells |
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Term
| Where do climbing fibers come from as opposed to mossy fibers? |
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Definition
climbing = inferior olive
mossy = afferents from nearly all other nuclei |
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Term
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Definition
| conduct signals rather rapidly & end in the granular layer, establishing synapses with the granule cell dendrites |
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Term
| What effect do mossy fibers have on Purkinje cells? |
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Definition
| they transmit action potentials with a high frequency to make the Purkinje cells fire simple spikes with a frequency of 50 to 100 per second |
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Term
| What effect do climbing fibers have on Purkinje cells? |
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Definition
| even a single action potential in a climbing fiber elicits a burst of action potentials in the Purkinje cells (complex spikes) |
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Term
| Is the inferior olive important for motor control? |
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Definition
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Term
| The globus & emboliform nuclei (the two small nuclei of the cerebellum) in humans are referred to as what in animals? |
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Definition
| the anterior & posterior interposed nuclei |
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Term
| 3 parts of longitudinal localizations |
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Definition
1. the vermis sends fibers to the fastigial nucleus
2. the intermediate zone to the interposed nuclei
3. the hemispheres to the dentate nucleus |
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Term
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Definition
| when neurons fire without any obvious excitatory input |
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Term
| Do cerebellar nuclear neurons have pacemaker properties? |
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Definition
| yes! they have intrinsic properties that depolarize the membrane even in the absence of an excitatory input |
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Term
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Definition
| firing of assembles of functionally related Purkinje cells; fundamental for cerebellar learning |
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Term
| Where do fibers from the dentate nucleus leave the cerebellum? |
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Definition
| through the superior cerebellar peduncle |
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Term
| With diseases of the cerebellum, do symptoms occur on the ipsilateral or contralateral side of the body? |
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Definition
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Term
| What is the main symptom of damage to the anterior lobe of the cerebellum? |
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Definition
| a change of muscle tone; especially gait ataxia |
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Term
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Definition
| instead of occurring simultaneously in several joints, movements take place in one joint at a time |
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Term
| What do all elements of ataxia have in common? |
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Definition
| a fundamental defect in control of the force & of the exact timing of the starting & stopping of movements |
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Term
| What aspect of ataxia is especially due to the cerebellum? |
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Definition
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Term
| Do cerebellar lesions affect the ability to learn conditioned responses? |
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Definition
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Term
| Is the cerebellum important for the perception of rhythm? |
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Definition
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Term
| How does a cerebellar lesion affect attention? |
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Definition
| the ability to rapidly shift the attention from one kind of stimulus to another is decreased |
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