Week 12 Content Flashcards
What is ataxia
The loss of order/coordination
What do movements require
Even simple movements require proper coordination to allow for smooth movements
- Agonist and antagonist muscles are working in sync
- Timing, magnitude, and rhythm of movement needs to be working properly
Intermediate cerebellar hemisphere lesion symptoms
- Pendular reflexes
- Ataxia
These symptoms occur primarily in the distal limbs
What are pendular reflexes
A lack of a singular/shortened response to a stimulus (i.e. swinging leg after a knee tap)
What does ataxia in intermediate cerebellar hemisphere lesions involve
- Dysrhythmia
- Dysmetria
- Intentional/action tremor
- Dysdiadochokinesia
- Dysarthria
What is dysrhythmia
Abnormal timing of movement
What is dysmetria
Abnormal amplitude of movement
- Leads to improper movement trajectories
What is an intentional/action tremor
A tremor that occurs only during voluntary movement that worsens throughout the movement durationW
What is dysdiadochokinesia
Difficulty with fast alternating movements
What is dysarthria
Poor flow and rhythm of speech
- Irregular in volume and tone
Tests for intermediate cerebellar hemisphere lesions
- Finger-nose-finger test
- Holding limbs up in front of you
- Maintaining a regular rhythm
Midline cerebellar/vermis lesions symptoms
- Ataxia of the legs, hips, and trunk (during sit and stand)
- Broad based staggering gait (ataxic gait)
- Poor standing posture
What causes anterior lobe syndrome
Typically chronic alcoholism with poor nutrition
- Causes truncal ataxia and an ataxic gait
What does the flocculonodular lobe/inferior vermis do
Coordinates balance and eye reflexes
- Vestibular coordination function
Flocculonodular lobe/inferior vermis lesion symptoms
- Unstable when standing and walking (normal when seated/reclined)
- Difficulty with smooth visual tracking of moving objects
- Inability to suppress the visual ocular reflex
What makes up the basal ganglia
Five interconnect nuclei deep in within the white matter of the cerebral hemispheres
What are the the five interconnected nuclei
- Caudate
- Globus Pallidus
- Putamen
- Subthalamic Nucleus
- Substantia Nigra
Caudate Nucleus (anatomy)
- C-shaped
- Head (wider)
- Body
- Tail (tapers off)
What does the caudate nucleus create
The lateral wall of the lateral ventricles
What sits at the tail of the caudate nucleus
The amygdala
Where is the caudate nucleus relative to the internal capsule
Medial
What are cellular bridges
White matter that connects the caudate to other regions of the basal ganglia on the other side of the internal capsule
What makes up the globus pallidus
- Globus pallidus externus (GPe)
- Globus pallidus internus (GPi)
Where is the globus pallidus relative to the internal capsule
Lateral
- GPi is in between the internal capsule and GPe
Putamen (what and where)
- Largest and most lateral nuclei of basal ganglia
- Sits lateral to the GPe
What is the putamen connected to
The caudate nucleus via the cellular bridges (striatum)
Where is the subthalamic nucleus
Below the thalamus right at the junction where the midbrain starts
Where is the substantia nigra
- Most ventral part of the midbrain below the subthalamic nuclei
- Ventral to red nucleus
- Dorsal to cerebral peduncles
What makes up the substantia nigra
- ventral portion = pars reticulata
- dorsal portion = pars compacta
What makes the substantia nigra dark
Dopaminergic neurons
What is the lenticular nucleus made up of
- Putamen
- Globus pallidus
What is medial to the internal capsule
- Caudate
- Thalamus
What are lateral to the internal capsule
- Globus pallidus
- Putamen
What are the four main input channels of the basal ganglia
- Motor
- Oculomotor
- Prefrontal
- Limbic
Where do inputs to the basal ganglia project
- The striatum (either putamen or caudate)
- Motor channel projects to putamen
- Oculomotor and prefrontal channel project to caudate
- Limbic goes to both
Where do inputs to the basal ganglia come from
- Ipsilateral cortex (excitatory)
- Ipsilateral thalamus (excitatory)
- Ipsilateral substantia nigra pars compacta (excitatory and inhibitory)
Where do outputs from the basal ganglia come from
- Globus pallidus
- Substantia nigra pars reticulata
Where do outputs from the basal ganglia go to
- Ipsilateral thalamus
- Reticular formation
- Superior colliculus
