4 Types of brain imaging techniques:
Microelectrode: Examines individual neurons
Macroelectrode: Examines brain activity without
producing an image (Ex: EEG)
Structural Imaging: Shows image of brain structure
(EX: CAT scan, MRI)
Functional Imaging: Shows image of brain structure
and activity (Ex: EEG, MEG/MSI, PET Scan, fMRI)
Microelectrode
Studies the function of a single
neuron. The microelectrode is
thinner than a human hair.
Ending is charged and inserted
into neuron. Changes in
neurons documented. Mostly
used to study effects of
neurotransmitters
Macroelectrode
Used to obtain an overall picture
of the activity in particular
regions of the brain.
EEG: (electroencephalograph)
Electrodes are taped to the scalp
to detect brain waves (alpha
waves when asleep/relaxed, beta
waves when awake/alert). Can’t
see through skull, but can show
activity in brain.
Structural Imaging
CAT Scan (aka CT Scan)
(computerized axial tomography)
Creates 3D images of the brain
by combining X-rays from many
angles.
Structural Imaging (cont’d)
MRI (magnetic resonance
imaging)
Better images than CT scan.
Head surrounded by
magnetic field & brain
exposed to radio waves,
which causes hydrogen
atoms to be released.
Released energy mapped out
and made into image.
Functional Imaging
To see brain’s activity, not just
the structure.
EEG Imaging: Same as EEG, but
detected brain waves
transformed into an image
instead.
Functional Imaging (cont’d)
MEG/MSI: Like EEG Imaging, but
more precise in where activity is
taking place in the brain.
(magnetoencephalography/
magnetic source imaging)
Functional Imaging (cont’d)
PET scan (positron emission
tomography)
Uses radioactive energy to map
brain activity. Person injected
with radioactive substance.
When substance decays due to
activity of cells, positrons
emitted. More activity, higher
emissions. Mapped into image.
Functional Imaging (cont’d)
fMRI: (functional MRI)
Same as PET scan, but instead
measures movement of blood
molecules, which is an index of
neuron activity
Extremely precise images
collected rapidly, many times per
second. Doesn’t require
injection of radioactive materials.
4 Types of brain imaging techniques:
Microelectrode: Examines individual neurons
Macroelectrode: Examines brain activity without
producing an image (Ex: EEG)
Structural Imaging: Shows image of brain structure
(EX: CAT scan, MRI)
Functional Imaging: Shows image of brain structure
and activity (Ex: EEG, MEG/MSI, PET Scan, fMRI)