The Cerebellum, Midline Structures And Basal Ganglia Flashcards
Location of cerebellum
Immediately beneath the occipital lobe
What separates the cerebellum and occipital lobe
Tentorium cerebelli- a fold of dura
What connects the brainstem and cerebellum
3 pairs of cerebellar peduncles
Number of pairs of cerebellar peduncles
3
What are the walls of the fourth ventricle
Posterior pons and medulla ventrally
Cerebellum dorsally
How many lobes form the cerebellum
3
3 lobes of cerebellum
Anterior lobe
Posterior lobe
Flocculonodular lobe
What separates the anterior and posterior lobe of the cerebellum
Primary fissure
Where is the horizontal fissure in the cerebellum
Posterior lobe
Location of floculonodular lobe
Most ventral
Floculonodular lobe
Made up of flocculus and nodule
Where is the flocculus located
Beneath the cerebellar peduncles
Where is the nodule located
Midline
Is the anterior or posterior lobe of the cerebellum larger
Posterior
What divides the 2 hemispheres of the cerebellum
Vermis
Folia
Gyri in the cerebellum
Much smaller
Number of functional areas of the cerebellum
3
3 functional areas of the cerebellum
Spino-cerebellum
Cerebro-cerebellum
Vestibulo-cerebellum
What anatomical part of the cerebellum is the spino-cerebellum
Vermis
What anatomical part of the cerebellum is the cerebro -cerebellum
Lateral hemispheres
What anatomical part of the cerebellum is the vestibulo-cerebellum
Floculonodular lobe
Primary input of the spino-cerebellum
Spinocerebellar tracts
Primary input of the cerebro-cerebellum
Cerebral cortex
Primary input of the vestibulo-cerebellum
Vestibular system - inner ear
Which cerebellar peduncle does the spino -cerebellum receive its fibres from
Superior and inferior
Which cerebellar peduncle does the cerebro -cerebellum receive its fibres from
Middle
Which cerebellar peduncle does the vestibulocochlear -cerebellum receive its fibres from
Inferior
Function of spino-cerebellum
Correction and modulation of fine movements
Function of cerebro-cerebellum
Planning and coordinating movements
Function of vestibulo-cerebellum
Balance, posture, tone and stabilisation of eye movements
3 paired arteries supplying the cerebellum
Superior cerebellar arteries
Anterior inferior cerebellar arteries
Posterior inferior cerebellar arteries
Which artery does the superior cerebellar arteries branch from
Basilar artery
Which artery does the anterior inferior cerebellar arteries branch from
Basilar
Which artery does the posterior inferior cerebellar arteries branch from
Vertebral arteries
Cerebellar dysfunction
Heavy alcohol consumption or a lesion of the cerebellum such as a stroke or tumour may cause symptoms reflective of disruption to the cerebellum’s functions. The acronym VANISHED can be used to remember these symptoms:
Vertigo
Ataxia
Nystagmus
Intention tremor
Slurred speech
Hypotonia
Exaggerated past-pointing
Dysdiadochokinesia
Vertigo
as the cerebellum receives and processes a large amount of input from the vestibular system such as our sense of balance and the perception of movement, vertigo may be caused if it is damaged.
Ataxia
this term means poor coordination. Typically, it is obvious when observing a patient’s gait, as the patient may appear unstable, with a very wide step to try to stabilise themselves.
Nystagmus
this term refers to the subtle, rapid, backwards-and-forwards eye movements that can be observed when looking closely at a patient’s eyes at the extremes of their gaze. A small amount of horizontal nystagmus may be considered normal, but vertical or rotational nystagmus is almost always abnormal. There are other causes of nystagmus, but without a functioning cerebellum able to stabilise eye movements, patients may develop this symptom.
Intention tremors
tremors are features of various neurological diseases and vary in character. In contrast to a Parkinson’s disease tremor, a tremor caused by a cerebellar lesion is absent at rest and appears as the patient ‘intends’ to do something, such as put their arms outstretched, or pick something up. This is because the cerebellum is unable to correct and modulate fine movements to stabilise the arm and hand.
Slurred speech
coordination of fine movements is one of the functions of the cerebellum and this extends to the coordination of muscles involved in articulation of speech so cerebellar dysfunction may cause patients to have slurred speech.
Hypotonia
maintenance of tone and posture are functions of the vestibulocerebellum and therefore, cerebellar dysfunction will cause lack of tone.
Exaggerated past-pointing
this is observed when asking a patient to touch their own nose, then reach out to touch the tip of your finger as you hold it in front of them. Rapid correctional movements are coordinated by the cerebellum to ensure their finger touches the target. Patients with cerebellar dysfunction are unable to correct their movements, so often ‘overshoot’ your fingertip when reaching for it and ‘point past’ it.
Dysdiadochokinesia
often abbreviated to DDK, this symptom is demonstrated by asking a patient to rapidly alternate between touching the palmar and dorsal parts of their fingers onto the opposite palm. Patients with cerebellar dysfunction will struggle to coordinate this movement smoothly and will have difficulty rapidly pronating and supinating their forearms or will miss the palm entirely.
Corpus callosum
Primary connection between the left and right hemispheres of the cerebrum
A group of commissural fibres
What is the primary connection between the left and right cerebral hemispheres
Corpus callosum
Thalamus
Central structure that acts as a relay for numerous functions of the brain including motor, sensory, visual, auditory, cognitive and emotional pathways
Hypothalamus
Homeostasis- exerts control over numerous hormonal endocrine functions of the body and autonomic nervous system
Location of hypothalamus
Immediately below thalamus
Location of pituitary gland
At the end of a stalk (infundibulum)
Sits in the pituitary fossa (sella turcica) of the splendid bone
Optic chiasm immediately superior to it
Pituitary gland
Hormone secretion
Infundibulum
Stalk of pituitary gland
Pineal gland
Secretes melatonin- hormone controls our sleep-wake cycle
Location of pineal gland
Part of diencephalon
Located immediately posterior to the colliculi of the midbrain
What secretes melatonin
Pineal gland
Calcarine sulcus
Within this sulcus of the occipital lobe is the primary visual cortex
Limbic system
A group of deep brain structures that play a significant role in functions including learning, memory, emotional comtrol
What does the limbic system contain
Fornix
Mammillary bodies
Hippocampus
Parahippocampal Gyri
Cingulate gyrus and cingulate sulcus
Sections of the olfactory and insular cortex, thalamus, hypothalamus and nucleus accumbens and amygdala
Fornix
Similar in shape to corpus callosum but much smaller
Mammillary bodies
Small, round nuclei located at the anterior tip of the fornix
Location of hippocampus
Immediately inferior to the inferior horn of each lateral ventricle
Part of the temporal lobes
Hippocampus
Integral in converting short-term memory to long-term memory
Parahippocampal Gyri
Gyri of the temporal cortices located next to the hippocampi
Cingulate gyrus and cingulate sulcus
A large gyrus and associated sulcus that is superior to it which are located immediately superior to the corpus callosum on both sides of the cerebrum
Cingulum
Association fibres
Fibres that travel from the cingulate gyrus to other parts of the limbic system- namely the Parahippocampal gyrus
Association fibres
Fibres that connect different parts of the same hemisphere
Commissural fibres
Fibres that cross the commissures into the opposite cerebrum
Amnesia
As the limbic system, and particularly the hippocampus, is responsible for formation of memory and conversion of short-term memory into long-term memory, a head injury or a disease which affects this area of the brain can cause amnesia. Amnesia can be classified into retrograde amnesia (meaning patients cannot recall events that took place prior to the onset of amnesia) or anterograde amnesia (meaning patients cannot create new memories after the onset but are able to recall long-term memories of things prior to the onset).
Basal ganglia
A group of deep nuclei of the brain that contribute to the coordination, control and inhibition of motor function
5 named parts of the basal ganglia
Caudate nucleus
Globus pallidus
Putamen
Substantia nigra
Subthalamic nucleus
Caudate nucleus
A c-shaped structure that rest immediately medial to, and follows the curvature of the lateral ventricle
Globus pallidus
A triangular-shaped nucleus that can be divided into an internal and external part
Putamen
An oval-shaped nucleus found immediately lateral to the Globus pallidus
Substantia nigra
A black nucleus found in the midbrain
What does the Substantia nigra produce
Dopamine
Subthalamic nucleus
A small nucleus located inferior to the thalamus but superior to the Substantia nigra
Lentiform nucleus
Putamen and Globus pallidus
Striatum
Caudate nucleus and lentiform nucleus (Putamen and Globus pallidus)
Amygdala location
A small spherical nucleus at the tip of the inferior horn of the caudate nucleus
Amygdala function
Involved in memory and emotional responses such as fear and anxiety
Nucleus accumbens location
At the anterior junction between the caudate nucleus and outamen
Nucleus accumbens function
Plays a role in reward systems and is a subject of research in addiction
Which structures are part of the basal ganglia anatomically but functionally part of the limbic system
Nucleus accumbens
Amygdala
Internal capsule
A bundle of white matter tracts between the Globus pallidus and thalamus
Internal capsule function
Forms part of the route the majority of sensory and motor axons travelling to and from the cortex
Projection fibres as they connect the cortex to deeper structures
Projection fibres
Connect cortex to deeper structures
Corona radiata
Axons that pass from the internal capsule to the cortex
Shaped such a way that they radiate out of the internal capsule towards the cortex
Parkinson’s disease
Parkinson’s disease is caused by degeneration of the dopamine-producing neurones of the substantia nigra. This leads to a reduction in the passage of impulses within the basal ganglia which impairs the initiation and inhibition of movement. The most characteristic symptom is a ‘pill-rolling’ resting tremor. Other symptoms include a shuffling gait with small steps which is difficult to initiate and difficult to stop, ‘cogwheel’ rigidity best seen in the upper limb muscles, micrographia (very small handwriting) and a ‘mask-like’ loss of facial expression. Dopamine can be replaced with an oral precursor drug called levodopa which can temporarily reduce the severity the symptoms.
Huntington’s disease
Huntington’s disease (or Huntington’s chorea) is an autosomal-dominant genetic disorder that leads to gradual damage to cells in various places within the brain. Symptoms include mood and personality changes, cognitive impairment, and motor dysfunction. Within the basal ganglia, Huntington’s disease mainly affects the striatum, and this leads to the characteristic movement disorder known as ‘chorea’. Chorea involves sudden, jerky and uncontrollable movements of the face, arms and legs.
- What are the names of the three lobes of the cerebellum?
Anterior
Posterior
Floculonodular
- Which arteries supply the cerebellum?
Superior cerebellar
Anterior inferior cerebellar
Posterior inferior cerebellar
- Give four symptoms of a cerebellar stroke.
Vertigo
Ataxia
Nystagmus
Intention tremors
- Which structure connects the pituitary gland to the hypothalamus?
Infundibulum
- What is the function of the pineal gland? Describe where it is located in the brain.
Secretes melatonin involved in circadian cycle
Immediately superior to midbrain superior colliculi
- Which structures of the brain are located on each side of the third ventricle?
Thalamus
- Parkinson’s disease is caused by a lack of which neurotransmitter? Where is this neurotransmitter produced in the basal ganglia?
Dopamine
Substantia nigra
- The floors of the lateral ventricles are formed from which structure of the basal ganglia?
Caudate nuclei
- What is the name for the type of fibres that:
a. Connect corresponding regions of two hemispheres by crossing the midline.
Commissures
- What is the name for the type of fibres that:
b. Connect various cortical regions within the same hemisphere.
Association finres
- What is the name for the type of fibres that:
c. Connect the cortex to deeper parts of the brain.
Projection fibres
Arterial supply to the basal ganglia
Lenticulo-striate arteries
(Branches of ACA + MCA)
What part of the brainstem does the superior cerebellar peduncle connect to
Midbrain
What part of the brainstem does the middle cerebellar peduncle connect to
Pons
What part of the brainstem does the inferior cerebellar peduncle connect to
Medulla
In which lobe is the amygdala
Temporal lobe
3 parts of caudate nucleus
Head
Body
Tail
Is the Putamen or Globus pallidus more lateral
Putamen
