Answer
The CNS interprets a stimulus as more intense if it receives signals from a high threshold sensory neurons than if it receive signals only from low-threshold neurons.
Work Step by Step
There are two ways in which strength of stimulus is encoded: firing frequency, and firing threshold of sensory( stimulating neurons)
Different neurons have different firing ( excitatory) thresholds. A weak stimulus excites a few neurons with weak thresholds. In contrast, a strong stimulus facilitates recruitment of many neurons; this enable the CNS to judge the strength of the stimulus. For example, a weak stimulus may trigger a few action potentials( 6-10 APs). A strong stimulus is much more powerful and may trigger hundreds of APs ( 500-800).
