• Neuroiamging

March 5, 2019 0 Comment

• Neuroiamging,
The process of producing images of the structure or activity of the brain or other part of the nervous system by techniques such as magnetic resonance imaging or computerized tomography. Neuroimaging or brain imaging is the use of various techniques to either directly or indirectly image the structure function of the nervous system. Currently, there are multiple neuroimaging techniques that allow us to observe structure and/or function within the living brain. For example, magnetic resonance imaging (MRI) may be used to acquire high-resolution images of brain structure noninvasively. A special version of this technique, functional magnetic resonance imaging (fMRI), may be used to assess which areas of the brain are active. PET, like fMRI, makes use of hemodynamic (i.e., blood flow) measures to monitor brain function and is minimally invasive because of its use of radioactivity. Both fMRI and PET have been consistently used to understand “where” processing occurs in the brain. Techniques such as EEG and MEG are used for mapping the brain’s electrical activity on a millisecond timescale and thus can tell us “when” during task performance brain areas may be most active. Together, all of these technologies may be used to investigate which areas of the brain are active and when they are active, thus providing us with valuable insight into the function. 29
Types of neuroimaging:
fMRI is the most commonly applied method of functional neuroimaging . It relies on the hemodynamic blood oxygenation level dependent (BOLD) effect, which reflects the ratio between oxygenated and deoxygenated hemoglobin. The BOLD contrast is used to infer which areas of the brain are active and may be used to map response within superficial. as well as deep areas of the brain. This includes limbic, cerebellar, and even brainstem areas all putatively involved in therapeutic acupuncture. BOLD fMRI has high spatial resolution (1–3 mm3) and does not involve harmful radiation. However, it has limited temporal resolution because of the delay and temporal spread of the hemodynamic response, which is thought to peak seconds after neuronal activity. 29
Modern neuroimaging modalities: