Brain scanning can be done through EEG, PET, MRI, and fMRI scans via different methods. Neuroimaging, as well as brain scanning, is the use of various techniques to image the structure, function, or pharmacology of the brain directly or indirectly. It is a relatively recent field of study within medicine, neurology, and psychology.

Radiologists are physicians who specialize in the performance and interpretation of neuroimaging in the clinical context.

1. Electroencephalography (EEG) 

Electroencephalography (EEG) is a technique used to measure brain activity during various psychological states, such as alertness or tiredness. It aids in the identification of seizures and other medical disorders involving an excess or absence of activity in certain areas of the brain. Electrodes are implanted on the face and scalp to prepare for an EEG. The electrical potential of each electrode may be monitored after each electrode is properly positioned. The frequency and shape of the EEG signal vary depending on a person's condition (waking, sleeping, etc.). Patients with epilepsy have an increase in the amplitude of firing that is seen on the EEG record. The downside of EEG is that the electric conductivity — and hence the observed electrical potentials — can vary greatly across people and over time owing to the inherent conductivities of various tissues such as brain matter, blood, and bones. As a result, it is not always evident which part of the brain is sending a signal.

2. Positron Emission Tomography (PET)

Positron emission tomography (PET) scans detect levels of the sugar glucose in the brain to show where neuronal activation is occurring. Because activated neurons need glucose as fuel, this works. A tracer chemical linked to radioactive isotopes is injected into the blood as part of the scan. When certain areas of the brain activate, blood (with the tracer) is sent to give oxygen. This produces visible dots, which are subsequently detected by detectors and utilized to generate a video picture of the brain while executing a specific activity. PET scans, on the other hand, can only detect generic regions of brain activity rather than precise sites. Furthermore, PET scans are expensive and intrusive, limiting their utilization. They can, however, be employed in some medical diagnoses, such as Alzheimer's.

3. Magnetic Resonance Imaging (MRI)

Magnetic resonance imaging (MRI) and functional magnetic resonance imaging (fMRI) scans are the types of brain imaging that are most directly applicable to psychology. An MRI employs powerful magnetic fields to align spinning atomic nuclei (typically hydrogen protons) within bodily tissues, then disrupts the nuclei's axis of rotation and monitors the radio frequency signal produced when the nuclei return to their baseline condition. An MRI generates a picture of the brain structure through this technique. MRI scans are noninvasive, pose no danger to health, and maybe utilized on newborns, offering a constant technique of imaging across the development spectrum. One downside is that the patient must remain still for lengthy periods in a loud, crowded environment while the imaging is being conducted. The fMRI is a series of MRIs that uses the computer adaption of many pictures to quantify both the anatomy and functional activity of the brain. The fMRI, in particular, monitors signal changes in the brain caused by changing neural activity. An fMRI allows a patient to conduct mental activities while detecting the region of action through blood flow from one portion of the brain to another by collecting photos less than a second apart and displaying where the brain "lights up." When a person analyses visual information, for example, blood rushes to the back of the brain, where the occipital lobe is situated. MRIs can demonstrate when things happen, how brain regions change with experience, and which brain areas collaborate. They've been used to investigate a wide range of psychological phenomena, including (but not limited to) the brain activity of lying, the differences between novices and specialists when playing a musical instrument, and what happens inside our skulls when we dream.