The physical emission mechanisms differ, but both arise from the same population of massive stars, albeit at different stages of their life. Now take one last look at the radio and far-IR images. There is one emission peak in the radio map that does not correspond to any feature in the infrared image. The fact that it is at the edge of the photo is suggestive that the feature may not be associated whatsoever with Messier 101. It could be a foreground object within our Milky Way Galaxy or a background object in the distant Universe.
Some investigative work leads to the answer.
Now let us turn our attention to shorter wavelengths. Massive young stars born in these environments emit significant amounts of ultraviolet light. This image is dominated by electronic noise, similar to static on your AM radio, and the blue-black variations in the pixels are nothing more than random noise. The fuzziest and dimmest emissions regions near the center are probably associated with the disk of M101.