How does pic related work within the brain?

I have a rough understanding, but I've been seeing it around lately because people do "dopamine fasts" where they abstain from technology, porn, or any sort of "artificial high" to restore their dopamine receptors.

I understand how tolerance works (at least in terms of nicotine and other drugs) but this appears to be a different sort of theory.

Regardless, is this an effective way of restoring these receptors within the brain? Would it even matter? Am I retarded?