Basil Ganglia and Cerebellum Flashcards
What are the three lobes of the cerebellum?
Anterior, Posterior and Flocculondular
On the Arbor Vitae, what are the indentations referred to as?
Sulci or fissures
On the Arbor Vitae, what are the gyri called?
Folia
The white matter in the Arbor Vitae contains?
Grey matter
What is the small region of grey matter within the Arbor Vitae?
Deep cerebellar nuclei
What attaches the cerebellum to the brainstem?
Peduncles
What are the four deep cerebellar nuclei from lateral to medial?
Dentate, emboliform, globose and fastigial
What is the largest and most lateral nucleus of the deep cerebellar?
Dentate
What is the second largest and most medial nucleus of the deep cerebellar?
Fastigial
What are the three layers of the cerebral cortex?
Molecular layer (outer), Purkinje cell layer (middle), Granule cell layer (inner)
What afferent fibres to the cerebellum come from spinal cord?
Spinocerebellar fibers
What afferent fibres to cerebellum come from pons?
Pontocerebellar fibres
Where does the pontocerebellar fibres receive input from?
Cerebral cortex via corticopontine fibres
What afferent fibres to cerebellum come from the vestibular nuclei?
Vestibulocerebellar fibres
What afferent fibres to cerebellum come from the inferior olivary nucleus?
Olivocerebellar fibres
Where do the afferent projections to the cerebellum enter?
Via cerebellar peduncles
How do the afferent projections reach the cerebellar cortex as?
Climbing fibres or Mossy fibres
Where do climbing fibres originate?
In the inferior olivary nucleus
Cerebellar afferents from other sources end as?
Mossy fibres
Explain the synapse of the climbing fibres?
Synapse discretely but extensively on a purkinje cell
Explain the synapse of the mossy fibres?
Synapse diffusely on Granule cells in the granule cell layer
From the cerebellum the only output is via?
The axons of purkinje cells
Where do purkinje cells synapse?
On neurons of the deep cerebellar nuclei
What purkinje cells project directly to vestibular nuclei?
Flocculonodular
What axons of the deep cerebellar nuclei cross the midline and synapse in the thalamus?
Efferent
Where does the thalamus send fibres to?
Motor cortex
Deep cerebellar nuclei sends fibres to?
Vestibular nuclei, red nucleus and reticular formation
What are the functional divisions of the cerebellum?
Vestibiulocerebellum, Spinocerebellum and Pontocerebellum
What does the vestibulocerebellum consist of?
Flocculonodular lobe
Where does the vestibulocerebellum receive input from?
Vestibular nuclei
What is the main function of the vestibulocerebellum?
Maintaining balance
Where does the vestibulocerebellum project to?
Reticular formation and vestibular nuclei and from there to the spinal cord
How does the vestibulocerebellum project from the vestibular nuclei to the spinal cord?
Via reticulospinal and vestibulospinal tracts
What does the spinocerebellum consist of?
The vermis and globose and emboliform nuclei
What is the main function of the spinocerebellum?
Posture and muscle tone
Where does the spinocerebellum receive input from?
Spinocerebellar tracts carrying proprioception, touch and pressure information
Where does the spinocerebellum project via DCN to?
Thalamus, red nucleus, reticular formation and vestibular nucleus
What does the pontocerebellum consist of?
Cerebellar hemispheres and dentate nucleus
What is the main function of pontocerebellum?
Muscle coordination
Where does the pontocerebellum receive input from?
Pontine nuclei
What nuclei receives fibres from the cerebral cortex?
Pontine nuclei
Where does the pontocerebellum project to?
Thalamic area that projects into motor cortex and red nucleus
What are the three peduncles of the cerebellum?
Superior cerebellar peduncles, Inferior cerebellar peduncle and Middle cerebellar peduncle
What are the afferent fibres of the superior cerebellar peduncles?
Ventral spinocerebellar tract and Tectocerebellar fibres
What are the efferent fibres of the superior cerebellar peduncle?
Cerebellothalamic fibres
What are the afferent fibres of the middle cerebellar peduncle?
Pontocerebellar fibres
Is there any efferent fibres of the middle cerebellar peduncle?
No
Describe a middle lesion?
Disturbance of postural control
Patient will tend to fall over when standing or sitting despite preserved limb coordination
Describe unilateral hemispheric lesion?
Disturbance of coordination in limbs.
Results in intention tremor and instead gait in the absence of weakness or sensory loss
Lesions will affective ipsilateral side of the body
Describe the bilateral cerebellar dysfunction?
Results in slowed, slurred speech (dysarthria)
Bilateral incoordination of the arms and a staggering, wide based gait (cerebellar ataxia)
Acute alcohol exposure results in?
Bilateral cerebellar hemisphere dysfunction and presents with cerebellar ataxia
What are the functions of the basal Ganglia
To facilitate purposeful movement
Inhibit unwanted movements
Role in posture and muscle tone
What is the basal ganglia?
A number of masses of grey matter located near the base of each cerebral hemisphere
What is involved in the basal ganglia?
Corpus striatum, Striatum, Pallidum, Subthalamic nucleus and Substantia nigra
What is the corpus striatum?
A region of grey matter associated with the lateral ventricle
What is involved in the corpus striatum?
Striatum and Pallidum
Caudate nucleus, putamen and globus pallidus
What does the striatum include?
Caudate nucleus and putamen
What does the palladium include?
Globus pallidus
What are the putamen and globus pallidus referred to as?
Lentiform nucleus
Where is the anterior limb of internal capsule between?
Lentiform and caudate nuclei
Where is the posterior limb of internal capsule between?
Lentiform nucleus and thalamus
Location of basal ganglia in axial brain slices?
Head of caudate nucleus, Putamen, Globus pallidus and tail of caudate nucleus
Location of the basal ganglia in coronal brain slice?
Caudate nucleus, Putamen and Globus pallidus
Where is the subthalamic nucleus?
Below the thalamus
Where does the striatum receive input from?
Cerebral cortex (corticostriatal)) Thalamus (Thalamostriatal) Substantia nigra (Nigrostriatal)
Where does the striatum send fibres to?
Globus pallidus (striatopallidal) and Substantia nigra (striatonigral)
Where does the globus pallidus receive input from?
Straitum (Striatopallidal) and Subthalamic nucles (Subthalamopallidal)
Where does the globus pallidus send fibres to?
Thalamus (palladothalamic) and Subthalamic nucleus (pallidosubthalamic)
Pons
What side of the body does unilateral lesions of the basal ganglia affect?
Contralateral
Lesions of the basal ganglia do not cause?
Paralysis, sensory loss, loss of power or ataxia
What do lesions of the basal ganglia cause?
Abnormal muscle control, changes in muscle tone, dyskinesias including: tremor, chorea and myoclonus
What are the two disorders associated with basal ganglia?
Parkinsons Disease and Huntingtons Disease
Describe Parkinsons disease?
Pathology: Degenration of dopaminergic neurons of the substantial nivea
Signs: Akinesia, rigidity and resting tremor
Describe Huntington’s disease?
Genetics: Autosomal dominant disorder
Pathology: progressive degeneration of the basal ganglia and cerebral cortex
Signs: Chorea and progressive dementia