Brain Imaging Technology

Phernology

1800

This method of neuroimaging grew to be popular in the United States and Europe. It was created by Franz Joseph Gall, a physician, who thought various sections of the brain could be read by feeling contours of the skull. These sections were then split into different "personalities" where the strongest traits were the biggest and were felt as bulges. This method lacked scientific evidence, but the idea that brain functions are localized to certain areas of the brain did prove to be accurate.

Human Circulation Balance

1800

Angelo Mosso, an Italian physiologist created a contraption that is thought to be the first actual neuroimaging technique. It was a noninvasive method that measured redistribution of blood during different activities, including intellectual and emotional activities. His belief was that the brain required more blood when it worked harder. The exact contraption is unknown, but is thought to look like the picture. This technique also has similarities to popular techniques used today.

Pneumoencephalography

1918

American neurosurgeon, Walter Dandy, introduced a technique where x-ray images of the brain's ventricular system were seen by injecting air into one or both ventricles of the brain. It involves "removing the cerebral spinal fluid and replacing it with air." It helps to detect tumors that may create changes in the ventricle. The procedure was very painful and had lots of side effects that could be long lasting. It was performed until the late 1970s.

Cerebral Angiography

1920

Egas Moniz, a neurology professor is reported to be the first person to complete a radiographic image on a living person's brain. This method uses x-rays to create images that find blockages or abnormalities in the head's blood vessels. It involves injecting radioactive dyes into the blood which helped get a clear picture. At first, the injection would be directly into the carotid artery, but has since been replaced by threading a catheter because of risks associated with the process.

Electroencephalography (EEG)

1924

The first known use of EEG on humans was by the German physiologist, Hans Berger. It is neuroimaging that detects electrical activity in the brain. EEGs are made of small metal discs that attach to a person's scalp. Communication impulses are recorded in wave patterns and has high temporal resolution so it can quickly pick up frequencies. However, it has poor spatial resolution so it doesn't know exactly where activity is taking place.

Positron Emission Tomography (PET)

1950

Gordon Brownell and other employees at Massachusetts General Hospital contributed to the creation of PET technology. These images were further developed 1975, and are still popular today. PET scans measure levels of sugar glucose in the brain to see where neurons are firing. During PET scans, radioactive tracer is injected into the blood which goes to deliver oxygen creating visible spots. A downfall though is they are costly and invasive, and not very specific in findings.

Magnetic Resonance Imaging (MRI)

1980

Invented with contributions from many different researchers. First, the MRI was developed to gain spatial information which was turned into a signal using magnetic fields. They have been used to detect medical conditions and produce images of brain structure using magnetic fields. They are non-invasive and can be used on people of all ages.
https://www.ted.com/talks/allan_jones_a_map_of_the_brain/transcript