A reduction of autonomic arousal leads to diversion of blood flow to viscera and away from skeletal muscle of the body. Accordingly this leads to increased blood flow to the surface of glabrous skin and thereby an increase in palmar skin temperature.
Sahaja Yoga Meditation (SYM) practitioners appear to perform exactly the same overt task since, like conventional meditators, they appear to sit quietly. If however the physiological changes that occur are different then it would suggest that despite overt similarities, the biological events are quite different.
This would suggest that SYM (and hence presumably the mental silence experience) is physiologically atypical. The mental silence experience may be associated with a unique spectrum of physiological activity.