Advances in brain imaging techniques such as positron emission tomography (PET), single photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI), along with electro-encephalography (EEG), an earlier technique for monitoring brain activity are enabling scientists to produce remarkably detailed computer-screen images of brain structures and to observe neurochemical changes that occur in the brain as it processes information or responds to various stimuli such as drugs of abuse or drug abuse treatment medications.
PET, SPECT, MRI, and EEG can reveal the living human brain at work by measuring the biological activity through the skull and. Each technique has its own advantages and each provides different information about brain structure and function.
Why should I be aware of this?
- Brain scanning and imaging have made considerable advancements where sophisticated package of miniaturised electronics are able to pick up the tiny electrical fields generated by the workings of the brain.
- In recent months scientists have used the technology to watch the formation of emotions ranging from love and lust to anger and disgust. They have also watched decisions being made, measured academic ability, spotted the mental signature of psychopathy and seen the hitherto invisible advance signs of devastating diseases such as Alzheimer’s. 
All about brain imaging
So far it has not been easy to get an idea of the workings of the brain. With most other parts of the body, postmortem dissection could give researchers a rough idea of their workings. But as brains lack moving parts, use of electrical impulses put it beyond easy understanding. For this reason, till the end of the last century researchers depended on brain-damaged patients to learn how the brain worked.
Then, in the 1980s, a range of new technologies began to emerge, including positron emission tomography (Pet) computerised axial tomography (Cat) and, perhaps the best known, functional magnetic resonance imaging (fMRI).
Gauging consumer desires
Some large corporations are availing brain scanning techniques to help them understand the consumers’ deepest thoughts and desires. Some scientific entrepreneurs are now marketing brain-scanning techniques to big corporations, suggesting they can use them to reveal our deepest thoughts and desires.
Brain scans can reveal the role of the subconscious in consumer purchase decisions which are expected to give corporations a better idea of how to market and improve their products.
Advanced lie detection
The greatest commercial attention is, however, focused on the idea that brain-scanning can be used as a form of advanced lie detection.
Five years ago fMRI researchers at Temple University in Philadelphia found that telling the truth activates the cingulate gyrus, in the middle of our brains, while lying lights up the limbic lobes, which are near the front, and also consumes more brain energy.
Since then several companies have sprung up to exploit such findings, including No Lie MRI Inc of Tarzana, California, which offers honesty scans for use in everything from dating to business deals. 
Other brain imaging techniques
- Positron Emission Tomography (PET) uses trace amounts of short-lived radioactive material to map functional processes in the brain.
- Electroencephalography (EEG) is the measurement of the electrical activity of the brain by recording from electrodes placed on the scalp. This is a non-invasive process and is frequently used in experimentation
- Magnetoencephalography (MEG) is an imaging technique used to measure the magnetic fields produced by electrical activity in the brain via extremely sensitive devices known as SQUIDs. These measurements are commonly used in both research and clinical settings.
- Near infrared spectroscopy (NIRS) is an optical technique for measuring blood oxygenation in the brain. NIRS can provide an indirect measure of brain activity.
- In one recent paper scientists reported they had found the seat of human wisdom by pinpointing the parts of the brain that become active when we face moral dilemmas.
- In another they found that unconditional love, experienced as a desire to care for another person without any thought of reward, emerged from interplay between seven separate areas of the brain.
- Last month researchers even suggested they could use a variant of fMRI, called diffusion tensor imaging, to show how people with high IQs think faster.
- The Basics of Brain Imaging
- They know what you're thinking: brain scanning makes progress
- Other brain imaging techniques