Neuroscience for Kids

BrainImaging

Recent technology has enabled neuroscientists to "see" insidethe living brain. These brain imaging methods help neuroscientists:
Understand the relationships between specificareas of the brain and what function they serve.
Locate the areas of the brain that are affectedby neurological disorders.
Develop new strategies to treat brain disorders.

Procedure Method
Computed TomographyScan
(CT Scan) CT scans use a series of X-ray beams passed throught the head. Theimages are then developed on sensitive film. This method createscross-sectional images of the brain and shows only the structure of the brain, not its function.
Positron Emission Tomography
(PET)

Image courtesy of the NationalInstitute on Drug Abuse
A scanner detects radioactive material that was injected or inhaled to produce an image of the brain. Commonly used radioactively-labeled material includes oxygen, fluorine, carbon and nitrogen. When thismaterial gets into the bloodstream, it goes to areas of the brain that useit. So, oxygen and glucose accumulate in brain areas that aremetabolically active. When the radioactive material breaks down, itgives off a neutron and a positron. When a positron hits anelectron, both are destroyed and two gamma rays are released. Gammaray detectors record the brain area where the gamma rays are emitted.This type of method provides a functional view of thebrain.
Advantages:
Provides an image of brainactivity.
Disadvantages:
Expensive to use.
Radioactive material used.
Magnetic Resonance Imaging
(MRI)
MRI uses the detection of radiofrequency signals produced by displacedradio waves in a magnetic field. It provides an anatomical view of thebrain.
Advantages:
No X-rays or radioactive material is used.
Provides detailed view of the brain in different dimensions.
Safe, painless, non-invasive.
No special preparation (except the removal of all metal objects) isrequired from the patient. Patients can eat or drink anything before theprocedure.
Disadvantages:
Expensive to use.
Cannot be used in patients with metallic devices, like pacemakers.
Cannot be used with uncooperative patients because the patient mustlie still.
Cannot be used with patients who are claustrophobic (afraid of smallplaces). However, new MRI systems with a more open design are nowavailable.
Functional Magnetic Resonance Imaging
(fMRI) Functional MRI detects changes in blood flow to particular areasof the brain. It provides both an anatomical and a functional view of thebrain.
Angiography Angiography involves a series of X-rays after dye is injected into theblood. This method provides an image of the blood vessels of the brain.

Procedure	Method
Computed TomographyScan (CT Scan)	CT scans use a series of X-ray beams passed throught the head. Theimages are then developed on sensitive film. This method createscross-sectional images of the brain and shows only the structure of the brain, not its function.
Positron Emission Tomography (PET) Image courtesy of the NationalInstitute on Drug Abuse	A scanner detects radioactive material that was injected or inhaled to produce an image of the brain. Commonly used radioactively-labeled material includes oxygen, fluorine, carbon and nitrogen. When thismaterial gets into the bloodstream, it goes to areas of the brain that useit. So, oxygen and glucose accumulate in brain areas that aremetabolically active. When the radioactive material breaks down, itgives off a neutron and a positron. When a positron hits anelectron, both are destroyed and two gamma rays are released. Gammaray detectors record the brain area where the gamma rays are emitted.This type of method provides a functional view of thebrain. Advantages: Provides an image of brainactivity. Disadvantages: Expensive to use. Radioactive material used.
Magnetic Resonance Imaging (MRI)	MRI uses the detection of radiofrequency signals produced by displacedradio waves in a magnetic field. It provides an anatomical view of thebrain. Advantages: No X-rays or radioactive material is used. Provides detailed view of the brain in different dimensions. Safe, painless, non-invasive. No special preparation (except the removal of all metal objects) isrequired from the patient. Patients can eat or drink anything before theprocedure. Disadvantages: Expensive to use. Cannot be used in patients with metallic devices, like pacemakers. Cannot be used with uncooperative patients because the patient mustlie still. Cannot be used with patients who are claustrophobic (afraid of smallplaces). However, new MRI systems with a more open design are nowavailable.
Functional Magnetic Resonance Imaging (fMRI)	Functional MRI detects changes in blood flow to particular areasof the brain. It provides both an anatomical and a functional view of thebrain.
Angiography	Angiography involves a series of X-rays after dye is injected into theblood. This method provides an image of the blood vessels of the brain.

Here are some examples of using a combination of PET and MRItechniques:
ThalamusCortex
These 2 images show the averaged data from 14 subjects who received apainful injection of the chemical capsaicin intothe upper arm. The colored part of the images show increased blood flow(the PET) to the thalamus and primary somatosensory cortex after theinjection. The gray areas of the images (the MRI) show the brain anatomy.So using this method can identify the areas of the brain that are activeduring specific conditions. This technique could be used to study just about any other cognitive function.
(These two PET/MRI images were provided by Dr. Robert C. Coghill at theNational Institute of Dental Research. Dr. Coghill's pagehas more examples of using imaging to study pain.)
PET alone is also used to study different cognitive functions. Someexamples of how PET is used to study brain function can be found at Let's Play PET. Functional MRI has also been used to examine what parts of the brainare active during memory.