CEREBLLAR DYSFUNCTION Flashcards
The _________, located inferiorly,
which is phylogenetically the oldest portion of the
cerebellum and is much the same in all animals (hence
archicerebellum) .
It is separated from the main mass of
the cerebellum, or corpus cerebelli, by the__________
flocculonodular lobe
posterolateral fissure.
The anterior lobe, or paleocerebellum, which
is the portion rostral to the_____
primary fissure
The ____________,
consisting of the middle divisions of the vermis and
their large lateral extensions
posterior lobe, or neocerebellum
The
flocculonodular lobe receives special proprioceptive
impulses from the_________i and is therefore
also referred to as the vestibulocerebellum;
vestibular nucle
The anterior vermis
and part of the posterior vermis are referred to as
the _________ since projections to these parts
derive to a large extent from the proprioceptors of
muscles and tendons in the limbs and are conveyed to
the cerebellum in the dorsal spinocerebellar tract (from
the lower limbs) and the ventral spinocerebellar tract
(upper limbs) .
spinocerebellum,
The main influence of the spinocerebellum
appears to be on______ and _____
posture and muscle tone
The neocerebellum derives its afferent fibers indirectly from the cerebral cortex via the pontine nuclei and brachium pontis, hence the designation ________
pontocerebellum.
Lesions of the nodulus and flocculus
have been associated with a disturbance of ______
equilibrium
and frequently with nystagmus
The ________, which receives both peripheral and central projections (from motor cortex), influences postural tone and also individual movements of the ipsilateral limbs.
The lateral zone is concerned mainly with _______ but is also involved
in other functions.
intermediate
zone
coordination
of movements of the ipsilateral limbs
The projections from Purkinje cells are ______ whereas those from the nuclei are excitatory on other parts of the motor nervous system.
inhibitory
The deep cerebellar nuclei, in turn, project to the
cerebral cortex and certain brainstem nuclei via two
main pathways:
fibers from the dentate, emboliform,
and globose nuclei form the _______
enter the upper pontine tegmentum as the brachium
conjunctivum, decussate at the level of the inferior colliculus, and ascend to the __________ of the
thalamus and, to a lesser extent, to the intralaminar
thalamic nuclei
Some of the ascending fibers,
soon after their decussation, synapse in the _____
but most of them traverse this nucleus without terminating, and pass on to the thalamus
superior cerebellar peduncle,
ventrolateral nucleus
red nucleus,
A
small group of fibers of the superior cerebellar peduncle,
following their decussation, descend in the ventromedial
tegmentum of the brainstem via the central
tegmental fasciculus and terminate in the reticulotegmental
and paramedian reticular nuclei of the pons and
inferior olivary nuclei of the medulla.
Guillain-Mollaret triangle
The _________sends fibers to the vestibular
nuclei of both sides and, to a lesser extent, to other nuclei of the reticular formation of the pons and medulla
fastigial nucleus
The _______ project via the restiform body (inferior cerebellar
peduncle) to the contralateral cerebellar cortex and corresponding
parts of the deep cerebellar nuclei.
inferior olivary
nuclei
The
dentate nucleus receives information from the premotor
and supplementary motor cortices via the pontocerebellar system and helps to initiate _________
volitional movements
The _______ also receives
cerebrocortical projections via the pontocerebellar system;
in addition, it receives spinocerebellar projections
via the intermediate zone of the cerebellar cortex
interpositus nucleus
Also, the _________ appears to be
responsible for making volitional oscillations (alternating
movements) .
prepositus nucleus
The _________controls antigravity and
other muscle synergies in standing and walking; ablation
of this nucleus greatly impairs these motor activities
fastigial nucleus
The cerebellar cortex is configured as a stereotyped
________containing______types of neurons
three-layered structure
five
The outermost “molecular” layer of the cerebellum
contains two types of inhibitory neurons, the _____
and the ________
stellate cells
basket cells
The _______ constitute
the main output of the cerebellum, which is directed at
the deep cerebellar and vestibular nuclei
Purkinje cells are likewise entirely inhibitory and utilize
the neurotransmitter _______
Purkinje cell axons
gamma-aminobutyric acid (GABA)
The innermost “granular” layer contains an enormous
number of densely packed ______ and a few larger
________
granule cells
Golgi interneurons
The predominant afferent input to the cerebellum is
via the_________which are the axons of the ___________ and the projections from pontine, vestibular,
and reticular nuclei
mossy fibers,
spinocerebellar
tracts
Mossy fibers ramify in
the granule layer and excite Golgi and granule neurons
through special synapses termed ________
cerebellar glomeruli.
The other main afferent input is via the_______
which originate in the inferior olivary nuclei (olives) and
communicate somatosensory, visual, and cerebral cortical
signals
climbing fibers,
The climbing fibers have specific excitatory
effects on Purkinje cells that result in prolonged ________
“complex spike” depolarizations
Four of the five cell types of the cerebellar cortex
(Purkinje, stellate, basket, Golgi) are ________
inhibitory
Afferent fibers
to the cerebellum are of three types, two of which have
been mentioned above: (1) ________, which are the
main afferent input to the cerebellum, utilize aspartate.
(2) _______, which are the axons of cells in the
inferior olivary nucleus and project to the Purkinje cells of
the opposite cerebellar hemisphere.
3) _______, which project through the superior cerebellar peduncle and terminate on
the Purkinje and granule cells in all parts of the cerebellar
cortex.
Mossy fibers
Climbing fibers
Aminergic fibers
The__________ elaborate the excitatory
transmitter glutamate.
All the inhibitory cerebellar cortical
neurons appear to utilize ______
granule cell axons
GABA.
the fragmentation of a smooth movement into
a series of irregular, jerky components
decomposition
with cerebellar lesions, there is a _________ between the commanded act and the onset of movement
prolongation of the interval
Extensive lesions of one cerebellar hemisphere,
especially of the ________, cause mild hypotonia,
postural abnormalities, ataxia, and a mild weakness
of the ipsilateral arm and leg perceived by the patient
anterior lobe
Lesions
involving the superior cerebellar peduncle or the dentate
nucleus cause the most severe and enduring cerebellar
symptoms, which manifest mostly as ________
ataxia in the
ipsilateral limbs.
Damage in the _______ causes
vestibulocerebellar symptoms-namely, dizziness, vertigo,
vomiting, and nystagmus-in varying proportions
inferior cerebellum
With
cerebellar disease, the _________ of the movement
are not checked in the normal manner.
velocity and force
This side-toside movement of the finger as it approaches its mark tends to assume a rhythmic quality; it has traditionally
been referred to as i___________
intention tremor, or ataxic tremor
Holmes called it rubral tremor, and although the
______ may be the site of the lesion, the nucleus itself
is not necessarily involved in this type of tremor.
Instead, it is a result of interruption of the fibers of the superior cerebellar peduncle, which traverse the nucleus, for which reason it may be more properly called _______
red nucleus
“cerebellar outflow
tremor.”
Smooth pursuit
movements are slower than normal and require that the
patient make small _________ in an attempt
to keep the moving target near the fovea
“catch-up” saccades
nystagmus
caused by cerebellar disease depends on lesions of
the _______
vestibulocerebellum
disequilibrium
syndrome, with normal movements of the limbs,
corresponds more closely with lesions of the ________than with those of the flocculus and nodulus
anterior
vermis
acute cerebellar lesions and hypotonia
are associated with a depression of _________
fusimotor efferent
and spindle afferent activity
after strongly flexing one arm against a
resistance that is suddenly released, the patient may be
unable to check the flexion movement, to the point where
the arm may strike the face
Holmes’ rebound phenomenon,
________i.e., brief (50- to 100-ms),
random contractions of muscles or groups of musclesare,
in some disease processes, combined with cerebellar
ataxia
Myoclonic movements-
Cognitive changes show a wide range of subtle _________ in patients with disease apparently limited to the cerebellum
alterations of
memory and cognition, language function, and behavior
Th e ataxia of severe sensory neuropathy and o f posterior column or posterior spinal root disease (sensory
ataxia) simulates cerebellar ataxia; presumably this is a
result of involvement of the _______
_________ and _______
are prime examples of this type of disorder
large peripheral spinocerebellar
afferent fibers
Tabes dorsalis and sensory ganglionopathy
A cerebellar type of tremor
reaches an extreme form in the large-fiber polyneuropathy
related to antibodies against _________
but the features are closer to an enhanced action
tremor,
myelin-associated glycoprotein
