Doubling the interelectrode distances will have what effect on the waveforms?

Doubling the interelectrode distances can lead to an increase in the amplitude of the waveforms recorded. This effect occurs because the distance between electrodes directly influences the electrical potential measured from the neural sources. When the electrodes are placed further apart, they can better capture the spreading electrical activity, thus resulting in a stronger signal. This is especially true in electroencephalographic (EEG) recordings, where spatial resolution increases with interelectrode distance, allowing for a greater detection of the brain’s electrical activity.

While the other options may touch on important concepts in signal detection and processing, they do not accurately reflect the primary effect of increased interelectrode distance on the amplitude of the waveforms. Increasing slow activity and decreasing muscle artifact are influenced by different factors related to the system's filtering or the overall electrode placement rather than just the physical distance between electrodes.