Brain Imaging Flashcards
What are electrophysiological techniques for monitoring neuronal activity based on?
Changes in membrane potential of activated neurons
How does brain scanning techniques work?
By monitoring changes in energy metabolism required by activating neurons
What require energy of their operation?
Electrochemical gradients that move charged ions in and out of neurons
What is the source of energy for electrochemical gradients that move charged ions in and out of neurons?
Oxidation of glucose
How are glucose and oxygen delivered to the brain?
Cerebral circulation
What causes a local increase in cerebral blood flow in active areas?
Neurovascular linl
What do modern neuroimaging devices measure?
Changes in local cerebral blood flow and use them as an index of neural activity
What is the first functional technique to be developed?
Positron Emission Tomography (PET)
What is the procedure of positron emission tomography (PET)?
Involve injection into human subject radioactive tracers that are attached to compounds of biological interest such as drugs that bind to neurotransmitter receptors
How does the positron emission tomography (PET) work?
Rings of detectors around the subject’s head record the timing and position of gamma particles emitted by the nuclear isotope as it traverses the brain and decays
What can PET be used to do?
It can be used to produce maps of changes in local cerebral blood flow (CBF)
What has PET measurement led to?
Localisation in the human brain of sensory, motor and cognitive brain functions
What are the disadvantages of PET?
- requires the injection of radioactive tracers thus many people like children and women of child-bearing age cannot have PET scan
- number of measures taken during scan are limited
What is different non-invasive technique?
Magnetic Resonance Imaging (MRI)
What can the MRI do?
Provide very fine-grained images of brain structure