October 20, 2010

overgeneralizing results

I was reading an article for my Neuroscience seminar about how the uncoupling protein UCP2 is required for the exercise-induced changes that occur in the hippocampi of mice (Dietrich, Andrews & Horvath, 2008).  In comparison to UCP2ko mice, the researchers found that only wildtype mice showed increases in both oxygen consumption during mitochondrial respiration and in the number of synapses in the CA1 region of the hippocampus. The methods used in this paper were very straight forward and the researchers appeared to control very well for potential biases. It would be very difficult to argue the validity of these results. Therefore I will accept, as Dietrich, Andrews and Harvath conclude, that voluntary exercise in mice increases mitochondrial respiration, mitochondria number, and spine synapse density in the dentate gyrus and the CA1 region of the hippocampus, all of which are dependent on UCP2.

Just when I thought I had finally read a paper for my seminar that hadn't bothered me in some way, I came across this in the conclusion: "Our data illustrate the role of uncoupling proteins in promoting brain plasticity and their participation in physiological and pathological adaptations of the brain." Isn't that statement a tad bit broad for this relatively straight-forward study which really only assessed the importance of UCP2? Furthermore, multiple times throughout the paper, the researchers assert that they did not monitor the effects or levels of UCP3 or UCP5, two other predominant uncoupling proteins. What about UCP1? It has been found to have implications in generating heat in hibernating mammals - how would this come into play in exercise-induced brain function, if at all?

Overgeneralization of results in science can be problematic for the directions of future research. The conclusion of this paper would lead one to believe that all uncoupling proteins have been found to have the same implications on these processes as UCP2 did, when in fact they may not in the least. This concept got me thinking about a trade-off, between overgeneralization and over-specificity, which was perceptively blogged about a few days ago. In Science papers, overgeneralizing can mislead future research, and lead to oversight. On the other hand, being too specific about something could lead to frivolous research, wasting time and resources.

Perhaps for this paper, an appropriate way to conclude this paper would be to assert that UCP2 has been implicated in these mechanisms, but further research is required to determine whether or not all uncoupling proteins produce the same results.

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