A couple of scientific papers, if you're up for a deep dive
The default network is causally linked to creative thinking - https://www.nature.com/articles/s41380-021-01403-8
Creativity and the default network: A functional connectivity analysis of the creative brain at rest – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4410786/
Some articles aimed at a general audience:
The Creative Brain is Wired Differently – https://neurosciencenews.com/creativity-networks-8355/
Eureka! – https://www.psychologytoday.com/us/articles/201503/eureka