MRI and basal ganglia Flashcards
Where and what is the ventral striatum?
Deep the the globus pallidus, medial and down
thalamus is deep to IT
Involved in limbic system
What are the limbs of the internal capsule? (axial view)
Anterior limb
Knee - turn
Posterior limb
Retro-lenticular portion behind the putamen
What is the subthalamic nucleus?
Globus pallidus projects to the thalamus
Difference between the neostriatum and the corpus striatum of the basal ganglia?
neo - caudate nucleus and the putamen
corpus - caudate nucleus, putamen and globus pallidus
What connects the putamen and the caudate nucleus?
Bridges of grey matter between them
Also white matter but not the qs
How do basal ganglia fibre pathways travel?
Out to in… putamen to globus pallidus (to sometimes subthalamic nucleus) to thalamus which then projects back up into the basal ganglia
Others too
Why is the red nucleus red? How does it show on MRI?
Iron content
Black on MRI
Globus pallidus also has iron content so is much darker than its counterparts on MRI
(and subthalamic nucleus?)
What is BOLD contrast?
blood oxygen level ? contrast
Reflects blood flow changes secondary to neuronal activation
What are fMRIs used for?
Simple or complex tasks compared with a ‘rest’ state
Statistical analysis of significant changes in BOLD contrast demonstrates areas of ‘activation’ - overlaid on anatomical images
What can be shown on a fMRI?
control
visual separation
language activation
What hazards are there in MRI?
Static magnetic field - magnet
radiofrequency filed - heating patient - can cause burns
magnetic field gradients - can induce currents in the patients and their implants
Hazards from the actual scanner?
Acoustic noise - they are VERY LOUD scanners
Cryogens - liquid helium keeps magnet superconducting - helium would leak out
What is something to always be aware of in MRI rooms?
Unsafe equipment
OXYGEN CYLINDERS can be mri unsafe
