What pulse width (PW) is known to excite more motor fibers than sensory fibers?

The correct pulse width known to excite more motor fibers than sensory fibers is 0.5 ms (50 µs). This is primarily because of how the duration of the electrical pulse interacts with the thresholds of different types of nerve fibers.

Motor fibers, especially the large-diameter alpha motor neurons, have a lower threshold for stimulation and a higher conduction velocity compared to sensory fibers. A pulse width of around 0.5 ms is considered optimal for preferentially activating these larger motor fibers while still having some level of action on sensory fibers.

Longer pulse widths, such as 1.0 ms (100 µs) and 1.5 ms (150 µs), provide enough stimulation to engage a broader range of fibers, which can lead to excitation of sensory fibers alongside motor fibers, potentially diluting the specificity for motor response. Conversely, shorter pulse widths, like 0.2 ms (20 µs), may not provide sufficient duration to effectively stimulate both motor and sensory nerves, thus limiting their effectiveness in a clinical setting for activating motor pathways.

Therefore, a pulse width of 0.5 ms represents a balanced approach that maximizes the activation of motor fibers over sensory fibers, making it particularly valuable in neurophysiological