"CONCLUSION:
These data suggest that the hippocampus can be injured by long-term microwave exposure, which might result in impairment of cognitive function due to neurotransmitter disruption."
https://www.ncbi.nlm.nih.gov/pubmed/22998825

In this context is of interest how the hippocampus is working. The hippocampus is one of the few areas in the brain where there is neurogenesis in adulthood.
Adult neurogenesis in the hippocampus.
http://nwg.glia.mdc-berlin.de/media/pdf/neuroforum/2006-3.pdf

You may imagine how an by microwaves injured hippocampus is developing new neurons in the brain. Certainly, these new neurons are structured as handicapped as the hippocampus would be at the first place when it will be irradiated by microwaves.