methods of investigating brain function Flashcards
what is an EEG?
- used when we want to investigate the whole brain
- Electrical activity on the scalp from millions of neurons is detected and amplified to produce a continuous picture of activity in the brain over a time period
- Uses small, metal discs called electrodes attached to your scalp
define wave frequency
number of waves that pass a given point in a given time period
define wave amplitude
the magnitude of a reaction or of a stimulus
what are the positives for an EEG?
- Anyone can participate
- Cheap
- Non invasive
- Range of activities
- Very high temporal resolution
- Can detect fast changes
what are the negatives of an EEG?
- Must be connected to computer
- Electrical fields are mostly blocked by skull, can’t measure deep activity
- Sign is weak and spatial resolution is poor
- Don’t show specific area of activity
define functional imaging
study of human brain function based on analysis of data using brain imaging modalities
define temporal resolution
the accuracy of the scanner in relation to time
define spatial resolution
the smallest feature that a scanner can detect
what is the EEG used for?
- Diagnose seizures, strokes, epilepsy, brain injuring and tumors
- Sleep studies
- Confirm brain dead
what is an MRI?
MAGNETIC RESONANCE IMAGING
- STATIC imaging
- Magnetic fields and radio waves are rotated around the head
- Powerful magnet affects nuclei of atoms
- The waves are tuned to the hydrogen in water and energy released from the hydrogen atom is measured to produce a 3D image
- It also distinguishes between different types of soft tissue
what are the uses of an MRI?
- Creates high definition 3D image of brain or body
- Very useful for measuring the size of brain structures
what are the positives of MRI?
- Gives detailed knowledge of brain
- Non invasive
- No radiation
- Patient is conscious and awake
what are the negatives of an MRI?
- Expensive and time-consuming
- Claustrophobic > may cause anxiety
- Image needs to be seen by an expert
- Noisy
- Doesn’t show change in brain over time
what are the negatives of an MRI?
- Expensive and time-consuming
- Claustrophobic > may cause anxiety
- Image needs to be seen by an expert
- Noisy
- Doesn’t show change in brain over time
what is a PET scan?
POSITRON EMISSION TOMOGRAPHY
- DYNAMIC imaging
- Use a radioactive glucose to determine the location of greatest brain activity during a tsk
- Detects the rate of metabolism of injected substances such as radioactive glucose
- Records activity over minutes = scan every 40 seconds