Basal ganglia and Cerebellum Flashcards
Identify 1.
Precentral gyrus.
Identify 2.
Central sulcus
Identify 3.
Post central gyrus.
Identify 4.
Lateral fissure.
Identify 5.
Pons.
Identify 6.
Medulla.
Identify 7.
Cerebellum
Identify 1.
The cerebral hemisphere.
Identify 2.
Cerebellum
Identify 3
Spinal cord.
Identify 4.
Medulla.
Identify 5.
Pons
Identify 6.
Midbrain.
Identify 7.
Diencephalon
Identify 1.
Primary fissure
Identify 2.
Horizontal fissure.
Identify 3.
Flocculus.
- Part of the flocculonodular lobe.
Identify 4.
CN V - trigeminal.
Identify 1.
Falx cerebri
Identify 2.
Tentorium cerebelli
Identify 3.
Posterior cranial fossa
Identify 4.
Falx cerebelli
The cerebellum is attached to the brainstem via 3 stalks known as?
peduncles
The cerebellar cortex is divided into what three layers?
- Molecular layer (outer).
- Purkinje cell layer (middle).
- Granule cell layer (inner).
Afferent projections to the cerebellum arrive mainly from where?
- Spinal cord.
- Cerebral cortex.
- Vestibular apparatus.
Afferent projections to the cerebellum are relayed mainly from which parts of the spinal cord?
Somatic proprioceptors and pressure receptors.
Afferent projections to the cerebellum are relayed from the cerebral cortex via what?
The pons
Afferent projections to the cerebellum are relayed from the vestibular apparatus via what?
The vestibular nuclei
Afferent projections to the cerebellum enter via cerebellar peduncles and project mainly to which cell layer?
Granule cell layer.
Efferent projections of the cerebellum arise from which of its lobes?
All three lobes.
Output of efferent projections of the cerebellum is via what?
Axons of Purkinje cells
Axons of purkinje cells of the cerebellum mainly synapse where?
Neurons of the deep cerebellar nuclei
Efferent projections of the cerebellum contribute to coordinating what?
Functions of all of the motor tracts of the brainstem and spinal cord, i.e.
- Corticospinal
- Vestibulospinal
- Rubrospinal
Most efferent axons of deep cerebellar nuclei cross the midline to synapse where?
The thalamus
After efferent axons of deep cerebellar nuclei synapse in the thalamus, where does the thalamus then send fibres?
To the motor cortex
Cerebellar hemispheres influence which side of the body?
The ispilateral side.
Lesions of the right cerebral hemisphere will cause signs and symptoms on which side of the body?
The right side.
Cerebral hemispheres influence ipsilateral side of body.
A unilateral hemispheric lesion of the cerebellum will result in what?
Disturbance of coordination in the limbs.
e.g. intention tremor, unsteady gait +/- weakness/sensory loss.
Bilateral cerebellar dysfunction results in what?
Slower, slurred speech - Dysarthria.
- Bilateral incoordinatino of the arms.
- Staggering, wide based gait - cerebellar ataxia.
Acute alcohol exposure typically has what effect on the cerebellum?
Bilateral cerebellar hemisphere dysfunction presenting as cerebellar ataxia i.e. a staggering, wide-based gait.
A midline lesion of the cerebellum will cause disturbances to what?
Postural control.
- e.g. Patient will tend to fall over when standing or sitting despite preserved limb coordination.
What are the functions of the basal ganglia?
- facilitate purposeful movement.
- inhibit unwanted movement.
- contributes to posture and tone.
What is the basal ganglia composed of?
- Caudate nucleus.
- Putamen.
- Globus pallidus.
- Subthalamic nucleus.
- Substantia nigra.
The putamen and globus pallidus form what?
Lenticular nucleus
The caudate nucleus and putamen form what?
Striatum
The caudate nucleus, putamen and globus pallidus form what?
Corpus striatum.
Masses of grey matter located near the base of each cerebral hemisphere.
Basal ganglia.
Describe the pathology of Parkinson’s disease.
Degeneration of dopaminergic neurons of the substantia nigra.
Degeneration of dopaminergic neurons of the substantia nigra.
Parkinson’s disease
The basal ganglia and the motor cortex enhance normal movement by what?
The direct pathway.
How does the direct pathway allow the basal ganglia to work with the motor cortex to enhance normal movement?
By enhancing thalamus outflow to enhance desired movement.
How do the basal ganglia and motor cortex suppress unwanted movement?
The indirect pathway.
How does the indirect pathway allow the basal ganglia and motor cortex to suppress unwanted movement?
By inhibiting the outflow of the thalamus.
Unilateral lesions of the basal ganglia affect which side of the body?
The contralateral side.
Lesions of the basal ganglia generally do NOT cause what?
- Paralysis.
- Sensory loss.
- Loss of power.
- Ataxia.
Lesions of the basal ganglia cause what motor signs?
- Changes in muscle tone.
- Dyskinesias (abnormal involuntary movements) e.g. tremor, chorea, myoclonus.
Name three types of dyskinesias caused by lesions of the basal ganglia.
Tremor, chorea, myoclonus.
