Comment on "Cerebellar LTD and Learning-Dependent Timing of Conditioned Eyelid Responses"

Abstract
First, Koekkoek et al. argued that their magnetic method of measuring eyelid movement is superior to electromyogram (EMG) recording from the obicularis oculi. We previously showed that eyelid movement is essentially perfectly correlated with EMG measurement for conditioned eyeblink responses (CRs) (2, 3). EMG recording is slightly more sensitive, particularly for measuring CR onset latency, and is the current standard in freely moving animals. The only advantage of the method used in (1) is more accurate measurement of eyelid response to unconditioned stimulus (US), which is irrelevant to the study.