Transcript Psychology Unit 2 - Biological Bases of Behavior Brain Scans

Psychology
Unit 2 - Biological
Bases of Behavior
Brain Scans
5 PRIMARY WAYS TO
EXAMINE THE BRAIN.
EEG
CT
PET
MRI
fMRI
STRUCTURE &
ACTIVITY
EEG - Electroencephalograph
EEG measures brain waves/electrical activity
Seen a lot on sleep studies.
With skull cap or individual electrodes - can
measure brain activity
EEG - Electroencephalograph
Although not a "brain scan" as the term is usually used, one of the first -- and still
very useful -- ways of non-invasively observing human brain activity.
Records electrical signals from the brain made by hooking up electrodes to the subject's
scalp.
The pens trace the signals onto the graph paper.
State: asleep, awake, anaesthetized -- because the characteristic patterns of current
differ for each of these states.
Shows how long it takes the brain to process various stimuli.
Major drawback - cannot show us the structures and anatomy of the brain or really
tell us which specific regions of the brain do what.
CT/CAT SCAN - Computed Tomography
Uses x-rays to create a 3 dimensional image.
Nice view of soft tissue as well as denser bone
structure.
CT/CAT SCAN
Uses computer-processed Xrays to produce tomographic
images or 'slices' - crosssectional images are used for
diagnostic and therapeutic
purposes in various medical
disciplines.
Digital geometry processing is
used to generate a threedimensional image of the
inside of an object from a
large series of twodimensional X-ray images
taken around a single axis of
rotation.
PET SCAN - Positron Emission Tomography
Radioactive glucose to see functioning in the brain.
Functioning - where is activity occurring in the brain?
PET SCAN - Positron Emission Tomography
PET SCAN - Positron Emission Tomography
PET scan below shows 2 areas of the
brain (red & yellow) that become
particularly active when volunteers
read words on a video screen: the
primary visual cortex & an additional
part of the visual system, both in back
of the left hemisphere.
Other brain regions become especially
active when subjects hear words
through a headset, as seen in the PET
scan on the right.
MRI - Magnetic Resonance Imaging
Magnets/radio waves to see structure of the soft
tissue.
MRI - Magnetic Resonance Imaging
Sequential sections from an MRI of the brain, concurrently showing slices through
transverse, sagittal, and coronal planes (left to right).
MRI makes use of the property of nuclear magnetic
resonance (NMR) to image nuclei of atoms inside the body.
MRI can create more detailed images of the human body
than are possible with X-rays.
fMRI - Functional Magnetic Resonance Imaging
Functional neuroimaging procedure using MRI technology that
measures brain activity by detecting associated changes in
blood flow.
This technique relies on the fact that cerebral blood flow and
neuronal activation are coupled. When an area of the brain is in
use, blood flow to that region also increases.
Since the early 1990s, fMRI has come to dominate brain
mapping research because it does not require people to undergo
shots, surgery, or to ingest substances, or be exposed to
radiation.
These fMRI images are from a study showing parts of the brain lighting up on seeing
houses and other parts on seeing faces. The 'r' values are correlations, with higher
positive or negative values indicating a better match.
5 PRIMARY WAYS TO
EXAMINE THE BRAIN.
EEG
CT
PET
MRI
fMRI
STRUCTURE &
ACTIVITY