Brain Research Methods:
List of Invasive methods:
The only truly invasive method of brain research is:
Direct Electrode Stimulation
Other methods involve either drinking or injecting a contrast substance to help with
imaging, these are:
CT, PET and SPECT
List of Radioactive methods:
CT: Xrays from the machine.
PET and SPECT: The tracer substance ingested.
List of Types:
Functional: Direct Electrode Stimulation, EEG, TMS
Structural: CT, MRI
Both Function AND Structure: PET, SPECT and fMRI
Direct Electrode Stimulation:
-Invasive: YES
-Radioactive: NO
-Type: Functional
-Description: Measures a direct cause effect relationship
between electrically stimulating part of the brain by
touching it with an electrode, and a psychological response.
No longer used because it is extremely invasive and
not necessary due to the innovation of TMS.
TMS (Transcranial Magnetic Stimulation):
-Invasive: NO
-Radioactive: NO
-Type: Functional
-Description: Similar to Direct Electrode Stimulation, but
uses an electro magnetic coil to induce brain neurons to fire
rather than touching it with an electrode. Has an advantage
over Direct Electrode Stimulation because it is very noninvasive and works through the scalp
and skull.
rTMS
-Identical to TMS but uses repeated magnetic pulse, rather than a single pulse. This
causes disruption of brain activity in the effected area, temporarily impairing a
persons ability to perform a certain task.
EEG (Electroencephalograph):
-Invasive: NO
-Radioactive: NO
-Type: Functional
-Description: Detects the firing of neurons under
electrodes placed upon the scalp of the patient. Helps to
locate areas of brain activity while certain tasks are
performed.
CT (Computed Tomography) (CAT)
-Invasive: Non Radioactive Contrast substance injected
into blood steam.
-Radioactive: Yes, Contrast substance is not radioactive, but
xrays from CT machine are.
-Type: Structural
-Description: Uses a series of xray images to compile a
computer generated 3D image of a patients brain. The
injected Contrast substance highlights blood vessels in the brain, which helps
to interpret the CT images.
MRI (Magnetic Resonance Imaging)
-Invasive: NO
-Radioactive: NO (magnetic instead)
-Type: Structural
-Description: Uses magnetic fields and radio waves to detect
vibrations of atoms, and create a 3D image. Higher resolution
images than a CT Scan. Main disadvantage is that it cannot be
used on patients with metallic implants, as the high powered
magnets would cause damage to them.
PET (Positron Emission Tomography)
-Invasive: Injected radioactive tracer.
-Radioactive: YES (Tracer)
-Type: Functional AND Structural
-Description: Machine monitors the amount of glucose being
used within the brain to determine areas of higher activity.
Does so by detecting radioactive tracer injected into the
patients blood steam.
SPECT (Single-photon emission computed tomography)
-Invasive: Injected radioactive tracer.
-Radioactive: YES (Tracer)
-Type: Functional AND Structural
-Description: Very similar to a PET, main difference being
the SPECT tracer lasts longer the PET tracer, which helps
when monitoring tasks that take a lot longer. SPECT images
are also of a lower resolution to that of PET images, but this
can be overcome by combining SPECT images with a CT scan
(SPECT-CT).
fMRI (Functional Magnetic Resonance Imaging)
-Invasive: NO
-Radioactive: NO
-Type: Functional AND Structural
-Description: Uses MRI technology but further
enhanced with the detection of oxygen usage in the
brain, which relates to brain activity. No radioactivity or
invasive procedures, however no metallic objects can be
inside the patient.