T1 L8: Global brain activity Flashcards
What does EEG stand for?
Electroencephalogram
How does an EEG work?
It records summation of electrical activity
What are the 2 basic requirements for signal detection by an EEG?
- A whole population of neurones must be working in synchrony to generate a large enough electrical field
- These neurones need to be aligned in parallel so they can summate and not cancel out
What does the amplitude of an EEG depend on?
On how synchronous the activity of the underlying neurones is
Which waves are present on an EEG when the eyes are open VS when they’re closed?
Open: Alpha
Closed: Beta
What are the 3 functional states of sleep?
Awake, Non-REM, and REM
Give example of some structural imaging techniques
CT, MRI
They measure spatial configuration of types of tissue in the brain
Give examples of some Functional imaging techniques
Positron emission tomography (PET), fMRI
They measure moment-to-moment variable characteristics of the brain associated with changes in cognitive processing
How does an MRI collect a signal from the brain?
Magnetic fields of protons in the brain are orientated by 90 degrees to produce a measurable MR signal
What does a PET scan measure?
Changes in blood flow
What does and fMRI scan measure?
The concentration of O2 in the blood
What is the BOLD signal?
The blood oxygen-level-dependent contrast is the signal measured in an fMRI. It relates to the concentration of oxy- and deoxyhaemoglobin in the blood
What is the HRF?
It’s the haemodynamic response function. It describes the changes of the BOLD signal over time
