It was recently reported that a magnetic actuator, Magneto, can control neuronal firings at magnetic strength as low as 50 mT (ref. 1), offering an exciting non-invasive approach to manipulating neuronal activity in a variety of research and clinical applications. We investigated whether Magneto can be used to manipulate electric properties of Purkinje cells in the cerebellum, which play critical roles in motor learning and emotional behaviors2. Surprisingly, we found that the application of a magnetic field did not change any electrical properties of Purkinje cells expressing Magneto, raising serious doubt about the previous claim that Magneto can readily be used as a magnetic actuator1.