Functional Magnetic Resonance Imaging fMRI , brain function study

A functional magnetic resonance imaging (fMRI) study of the brain can actually determine between the regular and the occasional coffee drinker. Caffeine consistently slows blood flow by 25% to the gray matter of the brain, which contains the cells, and by 20% to the white matter, which contains the connecting nerve fibers. Heavy users of caffeine show more blood flow in the gray matter in the front of the brain when they had abstained for 30 hours, compared to those who infrequently ingest caffeine. With fMRI, the doctor can look inside the brain and observe the phenomenon of caffeine withdrawal in action. 

Recent evidence from functional magnetic resonance imaging (fMRI) studies of children followed from birth to adolescence suggest that childhood lead exposure (and by implication, fetal lead exposure) may have a significant and persistent impact on the ongoing reorganization of brain connections involved in language function.21... 

It is known that respiratory stimuli elicit neural activity in suprapontine areas (O Donnell et al. 2007). hi human studies (Fig. 1) respiratory-related evoked potentials (RREP), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI) have been used to study human brain activity induced by respiratory mechanical loads, reducing tidal volume, hypercapnia, and hypoxia (O Donnell et al. 2007). Neural activation has been reported in the primary sensory cortex, thalamus, hypothalamus, anterior cingulate, amygdala, anterior insular... 

Functional magnetic resonance imaging (fMRI) scanning to visualize brain activity relies primarily on the blood oxygen level dependent (BOLD) signal, an indirect measurement of cerebral blood flow associated with neuronal activity. In a prospective study of fMRI, 14 children were randomized to propofol 1 mg/kg by bolus injection followed either by propofol 4 mg/kg/hour or by midazolam 0.6 mg/kg/hour [80 ]. There were no differences in MRI time, and all studies were completed without movement or adverse events. The children in both groups required further boluses of sedation, and there were no differences in recovery time. Midazolam temporally affected neuronal activity and vascular response leading to a delay in functional response whereas propofol produced a similar activation pattern to non-sedated adults. 

NMR can be used for the accurate determination of nuclear moments. It can also be used in a sensitive form of magnetometer to measure magnetic fields. In medicine, magnetic resonance Imaging (MRI) has been developed, in which images of tissue are produced by magnetic-resonance techniques. Functional MRI (fMRI) can detect changes in blood flow that accompany neural activity and is therefore used to study brain function. See Feature. 

---