Recent Breakthroughs
Recent breakthroughs in non-invasive brain imaging have been somewhat limited because most of them have not been completely novel; rather, they are simply refining existing brain imaging techniques. fMRI is a perfect example of this from the early 1990s, and it still remains the most popular brain imaging technique available today.
Advances have been made in a number of ways regarding neuroimaging, and this section will cover some of the more prominent improvements including computational advances, transcranial magnetic stimulation, and nuclear magnetic resonance.
To begin with, much of the recent progress has had to do not with the actual brain imaging methods themselves but with our ability to utilize computers in analyzing the data. For example, substantial discoveries in the growth of human brains from age three months to the age of fifteen have been made due to the creation of high-resolution brain maps and computer technology to analyze these maps over various periods of time and growth (Thompson, UCLA). This type of breakthrough represents the nature of most breakthroughs in neuroscience today. With fMRI technology mapping brains beyond what we are already understanding, most innovators time is being spent trying to make sense of the data we already have rather than probing into other realms of brain imaging and mapping.
This can be seen more clearly in the fact that brain imaging archives are catching on and neuroinformatics is allowing researchers to examine thousands of brains rather than just a few (Lynch). Also, these archives are universalizing and standardizing formats and descriptions so that they are more searchable for everyone. For the past decade we have been able to get data and now our technology allows us to share findings and research much easier. This has also allowed for "brain atlases" to be made. Brain atlases are simply maps of what normal functioning brains look like (Thompson, Bioinformatics).
Transcranial magnetic stimulation (TMS) is a recent innovation in brain imaging. In TMS, a coil is held near a person's head to generate magnetic field impulses that stimulate underlying brain cells to make someone perform a specific action. Using this in combination with MRI, the researcher can generate maps of the brain performing very specific functions. Instead of asking a patient to tap his or her finger, the TMS coil can simply "tell" his or her brain to tap his or her finger. This eliminates many of the false positives received from traditional MRI and fMRI testing. The images received from this technology are slightly different from the typical MRI results, and they can be used to map any subject's brain by monitoring up to 120 different stimulations. This technology has been used to map both motor processes and visual processes (Potts link at bottom of TMS). In addition to fMRI, the activation of TMS can be measured using electroencephalography (EEG) or near infrared spectroscopy (NIRS).
Nuclear magnetic resonance (NMR) is what MRI and fMRI technologies were derived from, but recent advances have been made by going back to the original NMR technology and revamping some of its aspects. NMR traditionally has two steps, signal encoding and detection, and these steps are normally carried out in the same instrument. The new discovery, however, suggests that using laser-polarized xenon gas for "remembering" encoded information and transporting that information to a remote detection site could prove far more effective (Preuss). Separating the encoding and detection allows researchers to gain data about chemical, physical, and biological processes that they have been unable to gain until now. The end result allows researchers to map things as big as geological core samples or as small as single cells.
It is interesting to see how advances are split between those seeking a completely mapped brain by utilizing single neuron imaging and those utilizing images of brains as subjects perform various high-level tasks. Single neuron imaging (SNI) uses a combination of genetic engineering and optical imaging techniques to insert tiny electrodes into the brain for the purpose of measuring a single neuron's firing. Due to its damaging repercussions, this technique has only been used on animals, but it has shed a lot of light on basic emotional and motivational processes. The goal of studies in higher-level activities is to determine how a network of brain areas collaborates to perform each task. This higher-level imaging is much easier to do because researchers can easily use subjects who have a disease such as Alzheimer's. The SNI technology seems to be going after the possibility for AI while the network-probing technology seems to be more for medical purposes.
Read more about this topic: History Of Neuroimaging