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Clinical applications
Functional magnetic resonance spectroscopy (fMRS) uses the same scanning equipment as functional magnetic resonance imaging (fMRI) but with a different software. It is described as in vivo because it can be used to record the level change of different chemicals in the brain whilst the subject is thinking or performing a task. Thus analyses of the imaging allows for conclusions based on the functioning brain as opposed to just the neuroanatomy of the resting brain. The change in chemical levels in the brain is because of metabolism. The signals produced are then acquired as a waveform and over time being digitized and then processed in the computer software. The different chemicals being measured produce different signals that can be separated using the Fourier transform which is a mathematical computerized processing method.

There have been many technical advances for acquiring and analyzing high-quality MRS signals. Some of which involve using pulse sequences in the acquiring of data and controlling the timing of the different parts of the scanner. Examples of pulse sequences techniques include PEPSI (Proton EchoPlanar Spectroscopic Imaging), STEAM (Stimulated Echo Acquisition Method), and PRESS (Point Resolved Spectroscopy). Pulse sequences can be measured by single voxel or multiple voxel techniques. Single voxel technique obtain signal from only one specific known brain location while multiple voxel techniques can be used to obtain spectroscopic information from multiple voxels or regions of the brain, it can also be used to produce metabolite maps. Multiple voxel techniques are best used in studies whereby the exact region of interest is not known.

Chemicals
FMRS gives information about both the spatial position and chemical information of the brain. One group of chemicals that can be measured are known as metabolites. They are present at all stages of the metabolism process.

Lactate
One of the chemicals that can be measured is lactate, thought to be metabolized in the brain as an energy substrate for neurons, it is also a by-product of glucose metabolism during brain activation. FMRS has also been used to demonstrate an increase in lactate in normal adults during visual, auditory and cognitive tasks. Additionally, fMRS using the PEPSI (Proton EchoPlanar Spectroscopic Imaging) technique is also an example of an approach used to detect regional brain activation during a specific mental task.

Language
In the study of language function in the brain, fMRS has been used by the mapping of changes in certain chemicals during specific language tasks in response to brain activation. During different states the brain is in, the levels of brain chemicals are then measured. When performing a language task, the brain responds by using up energy and in turn producing chemical changes in the language areas of the brain, which are the Broca’s area and the Wernicke's area. MR spectroscopy allows us to view some of these chemicals (metabolites) non-invasively.

Auditory pathways
A common clinical syndrome, sudden sensorineural hearing loss is when patients lose useful hearing over a time of few minutes to hours. The absence of clinical markers that might help indicate the mechanisms that causes the disease hampers the efforts to develop treatment this clinical syndrome. There are current theories suggesting that reversible cases of such involve a reduce amount of cochlear blood flow and in nonreversible cases may be caused by a viral infection and accompanied by vertigo. In such cases, fMRS is used to study the biochemical changes produced by auditory stimuli in patients with sudden hearing loss as compared to that of healthy individuals, by the understanding of how the different proton metabolites are affected in the auditory pathways of the brain during a neuronal activity.

Anterior cingulate cortex
The anterior cingulate cortex (ACC) can provide a variety of important information in psychiatric disorders, where for example metabolites such as glutamine have been shown to be abnormal. However it is not easy to functionally activate the area and getting qualitative and reliable data is also a challenge because of its close proximity to sinuses. Due to its close proximity to the brain and its strong response to visual activation, fMRS can provide valuable information like the dynamic rate of concentration change in the brain. A study done detected phosphocreatine (PCr) changes showing the existing potential of fMRS being used in the ACC during the performance of a task and that using this technique could provide useful information on the metabolic dynamics in neuropsychiatric disorders.

Pain
Painful stimuli have been shown to activate the Anterior Cingulate gyrus (ACg) in which may reflect an increase in glutamate neurotransmission, which then through the conversion of glutamate and glial uptake yield an increase in glutamine. The use of fMRS technique in the study of pain to investigate the effects of pain shown that there is an increase in concentration of glutamate and glutamine due to an external painful stimulus. The increase in glutamine may indirectly reflect an increased glutamate neurotransmission, which is also reflected by the increased glutamate concentration. Results in these study highlighting the non-invasive measurement of glutamate and glutamine changes in the brain and glutamate neurotransmission introduces a new and unique tool for studying brain activation in vivo. With a combination of a dynamic spectroscopic imaging and fMRI in future studies will help with the determining of the specificity and time course of metabolic changes and can in turn prove to be a useful tool in the study of pharmacologic intervention in pain.

Migraine
Valuable information on functional disorders like migraine and a common theory linking habituation deficit to migraine can be provided through the studying of dynamic processes in brain metabolism. FMRI has become a popular choice to help with the mapping of different functional areas of the brain and the detection of biochemical changes during which neurons are activated. FMRS in this case can be used in the studying of the lactate concentration in the brain during visual stimulation using the single voxel technique. And also for the investigation of the metabolic component of habituation while migraine patients have a sustained visual stimulus, using fMRS allows the possibility to have both temporal and spatial resolution in the same spectroscopic imaging examination. Early stage test results shown a difference in the habituation behaviour between patients with migraine and that of healthy volunteers.