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 betweenelectricallystimulating part of the brain by touching it with an electrode, and a psychological response. No longer used because it is extremely invasive and notnecessarydue to theinnovationof TMS.
TMS (Transcranial Magnetic Stimulation):
-Invasive:NO
-Radioactive:NO
-Type:Functional
-Description:Similar toDirect Electrode Stimulation, but uses an electro magnetic coil to induce brainneuronsto fire rather than touching it with an electrode. Has an advantage overDirect Electrode Stimulation because it is verynoninvasive 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 personsabilityto 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 intoblood 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 tointerpretthe 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 (PositronEmissionTomography)
-Invasive:Injected radioactive tracer.
-Radioactive:YES (Tracer)
-Type:Functional AND Structural
-Description: Machinemonitorsthe 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 thedetectionof oxygen usage in the brain, which relates to brainactivity. Noradioactivityor invasiveprocedures, however no metallic objects can be inside the patient.