Reader Comments

Post a new comment on this article

Referee comments: Referee 3

Posted by PLOS_ONE_Group on 10 Apr 2008 at 16:19 GMT

Referee 3's review:

**********
N.B. These are the comments made by the referee when reviewing an earlier version of this paper. Prior to publication the manuscript has been revised in light of these comments and to address other editorial requirements.
**********

This paper presents evidence for the validation of a coil that can deliver interleaved sham and real TMS within trial blocks. For some paradigms, though not all, the delivery of sham vs real TMS is a problem and it seems that this coil will allow experimenters to do this. However, it is a problem that is often overstated and I think it is overstated here. There are ways around sham stimulation: for example here are two I have used.

1. if one is stimulating to get an effect at 100 msecs after onset of a task, it is easy to interleave other timings at 80, 90, 110 and 120. Neither the experimenter nor the subject is aware f this.
2. it is a trivial matter to control the intensity of TMS from a computer. So, if threshold +/- some amount is your chosen intensity it is possible to interleave lower intensities at which you would not predict an effect. Under task demands neither subjects nor experimenters will be aware of these changes of 10-15%.

Having said that, the paper is pretty straightforward and I am sure that some sections of the TMS community will be interested in it.

I would ask only three changes:
1. shorten the MS. It is not a theory paper and not really a methods paper, it is a description of a piece of kit.
2. Make it clear that sham is only necessary for SOME paradigms.
3. Make it clear that even with sham, control sites are necessary to ensure that disruption to a specific part of the system is the cause of the TMS effects.

Figure 1 is unnecessary.