Final answer:
Physiologic temporal dispersion affects sensory responses more than motor responses due to the variable nature of sensory pathways, which often include smaller, less myelinated fibers, and the role of integration in the CNS.
Step-by-step explanation:
Physiologic temporal dispersion refers to the phenomenon where nerve impulses travel at slightly different speeds, leading to a spreading out of the electrical signal over time. This dispersion generally has a greater impact on the sensory response when compared to the compound motor response. One reason is that motor responses involve the activation of multiple motor units which follow a relatively fixed, synchronized path, starting from the initiation at the motor cortex to the neuromuscular junction. The motor pathways have larger diameter axons and greater myelination, which allows for more synchronized transmission of the impulses.
In contrast, sensory responses are often subject to greater variability due to factors such as differences in the timing of when sensory information is received and processed. This variability can be due to a number of factors, including the different types of sensory receptors involved and the varying distances the sensory signals must travel to reach the central nervous system (CNS) for integration. Moreover, sensory pathways, with smaller diameter fibers and less myelination, can have more asynchronous transmission, thus being more susceptible to temporal dispersion.
Integration also plays a role in why sensory responses are affected more by temporal dispersion. As the sensory information arrives at different times, the CNS must integrate it with ongoing processes, such as comparing it with past experiences, or the current state of the body, to produce an appropriate response. The conscious perception of pain, as an example, might be delayed as it takes time to travel through the sensory pathways and be recognized by the cerebral cortex.