Rd
Banich & Compton (2011) Cognitive Neuroscience, 3 Ed. Wadsworth Cengage.
nd
Jamie Ward (2010). Student’s Guide to Cognitive Neuroscience, 2 Ed. Psychology Press
nd
M Gazzaniga, R Ivry & G Mangun (2002) Cognitive Neuroscience 2 Ed. Norton
Techniques for assessing brain anatomy
Computerized Axial Tomography (CAT SCAN)
• Uses x-rays to determine the density of the brain
• Cerebrospinal fluid (CSF) is less dense than brain tissue. Brain tissue is less dense
than blood. Blood is less dense than bone.
• Tissue that is dense will appear white and tissue/material that is more dense will
appear black. For example: bone will appear white and CSF will appear black
• CAT provides slides of the brain stacked on top of each other
• Regions of the brain that have been damaged in the past will appear darker than the
tissue that surrounds it due to being filled with less dense CSF
• Likewise, places where bleeding has occurred will be lighter because blood is less
dense than brain tissue
• The advantages of CAT scans is that they are not expensive and can be administered
to anybody
• The disadvantage is that the x-rays use radiation and patients get exposed to that
ionizing radiation
Magnetic Resonance Imaging (MRI)
• Technique that relies on the use of magnetic fields to distort the behaviour of protons
• This information is then used to create an image of the anatomy of the brain
• MRI relies on three magnetic fields:
• Static field – a constant magnetic field whose strength determines the strength of the
MRI machines. It causes all the magnetically sensitive particles to align themselves in
the same direction.
• Pulse sequence – an oscillating magnetic field. The time it takes for the protons to go
back to their original state (relaxation time) is recorded through a radio-frequency coil
that acts as a receiver coil (positioned around or near to the persons head).the
intensity of the signal received by the receiver coil indicates the concentration of the
particular substance in the brain.
• Gradient field – varies in intensity over the area being imaged. Provides a way to
identify particular locations which allows for the identification of where the signals
are coming from. A 3-d image of the brain is able to be formed due to spatial
information and signal intensity received.
• The advantages of MRI’s is that they do not require x-rays therefore there is no
ionizing radiation and the resolution of the image is much clearer
• The disadvantages are that it is costly and cannot be administered on individuals with
pacemakers
• There is a recently developed anatomical MRI method called diffusion tensor imaging
(DTI) which not only provides information about the structural integrity of brain
Banich & Compton (2011) Cognitive Neuroscience, 3 Ed. Wadsworth Cengage.
nd
Jamie Ward (2010). Student’s Guide to Cognitive Neuroscience, 2 Ed. Psychology Press
nd
M Gazzaniga, R Ivry & G Mangun (2002) Cognitive Neuroscience 2 Ed. Norton
Techniques for assessing brain anatomy
Computerized Axial Tomography (CAT SCAN)
• Uses x-rays to determine the density of the brain
• Cerebrospinal fluid (CSF) is less dense than brain tissue. Brain tissue is less dense
than blood. Blood is less dense than bone.
• Tissue that is dense will appear white and tissue/material that is more dense will
appear black. For example: bone will appear white and CSF will appear black
• CAT provides slides of the brain stacked on top of each other
• Regions of the brain that have been damaged in the past will appear darker than the
tissue that surrounds it due to being filled with less dense CSF
• Likewise, places where bleeding has occurred will be lighter because blood is less
dense than brain tissue
• The advantages of CAT scans is that they are not expensive and can be administered
to anybody
• The disadvantage is that the x-rays use radiation and patients get exposed to that
ionizing radiation
Magnetic Resonance Imaging (MRI)
• Technique that relies on the use of magnetic fields to distort the behaviour of protons
• This information is then used to create an image of the anatomy of the brain
• MRI relies on three magnetic fields:
• Static field – a constant magnetic field whose strength determines the strength of the
MRI machines. It causes all the magnetically sensitive particles to align themselves in
the same direction.
• Pulse sequence – an oscillating magnetic field. The time it takes for the protons to go
back to their original state (relaxation time) is recorded through a radio-frequency coil
that acts as a receiver coil (positioned around or near to the persons head).the
intensity of the signal received by the receiver coil indicates the concentration of the
particular substance in the brain.
• Gradient field – varies in intensity over the area being imaged. Provides a way to
identify particular locations which allows for the identification of where the signals
are coming from. A 3-d image of the brain is able to be formed due to spatial
information and signal intensity received.
• The advantages of MRI’s is that they do not require x-rays therefore there is no
ionizing radiation and the resolution of the image is much clearer
• The disadvantages are that it is costly and cannot be administered on individuals with
pacemakers
• There is a recently developed anatomical MRI method called diffusion tensor imaging
(DTI) which not only provides information about the structural integrity of brain
