Question

Explain what can be inferred by analyzing BOLD signals in fMRI studies. Briefly describe two limitations to fMRI. What approaches/solutions could you use to overcome these limitations?

Answer 1

fMRI tends to cover functional imagery of brain. As a non-invasive braining imaging method, fMRI has become the go-to workhorse of cognitive neuroscience. 1) neural activity is systematically associated with changes in the relative concentration of oxygen in local blood supply of the body 2) oxygenated blood has different magnetic susceptibility relative to deoxygenated blood 3) changes in the ratio of oxygenated/de-oxygenated blood can be inferred with fMRI by measuring the blood-oxygen-level dependent (BOLD) response. This means that the level of any neurochemical/biological changes in composition of blood can be tapped by the measure of BOLD signals in fMRI. All kinds of neural activity in the brain is tapped by this measure including the visual, motor, language functions and cognition. BOLD in general has high sensitivity and easy implementation. It is based on physiological and anatomical parameters. The limitations of fMRI consist of the fact that it is highly time consuming and expensive. Moreover, it has mediocre temporal resolution and is complex, high variable data analysis.