neuroscience - What are different firing rates in different regions in the human brain?

Could it for example be that neurons that are concerned with high-order thought and medium-term planning fire more slowly, or is it expected that all neurons rather fire more or less at the same rate?

Here is an article on the average firing rate: http://aiimpacts.org/rate-of-neuron-firing/

Is the assumption that the measurements tend to be biased by accounting only for visually responsive cells warranted?