brainfrontiers

Dead Salmon “haunts” fMRI data

The other day I posted a blog about research findings using functional Magnetic Resonance Imaging (fMRI) scans on Tibetan monks to locate changes in brain activity during meditation. Functional MRI is a type of specialized scan that can be used to measure the change in blood oxygen levels related to neural activity in the brain of humans or other animals. It is one of the most recently developed forms of neuroimaging and is widely used in the brain mapping field due to its relatively low invasiveness, absence of radiation exposure, and relatively wide availability.

fMRI scans are highly useful and DO provide accurate data about brain activity. However, most MRI specialists are aware that the statistical analyses used to derive those data must be carefully applied lest you run the risk of picking up false positives. For instance, blood oxygen levels which provide the signature of activation in the brain for fMRI scans is relatively weak and sources of noise in the acquired data must be carefully controlled. This means that a series of processing steps must be performed on the acquired images before the actual statistical search for behavior-related activation can begin. Case in point is this wonderful story found here about an Atlantic Salmon that despite being dead appeared to show brain activity in it’s “prefrontal cortex” when scanned in an fMRI. This story is a great read and makes you think twice about some of the conclusions reached in fMRI based research.

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