Complex sentence: Less is known about the physiological inputs of the low frequency (LF) activity (0.04 to 0.15 Hz), though recent consensus suggests it is influenced either by the SNS or a mixture of both the SNS and PSNS.
Split into simpler sentences: Less is known about the physiological inputs of the low frequency (LF) activity (0.04 to 0.15 Hz). It is thought to be influenced either by the SNS or a mixture of both the SNS and PSNS.