This 2015 rodent study used a genetic strain of mice that was bred to not express a gene that enabled long-term memory in the hippocampus. The mice were not memory-impaired, however, due to their brains’ neural plasticity.

The researchers found:

“Deletion of genes in organisms does not always give rise to phenotypes because of the existence of compensation.

The current work provides an example of how a complex brain system may adjust to the effects of gene deletion to recover function.”

The Early human brain development can be greatly modified by environmental factors study showed even greater plasticity in another part of the human brain where the people faced much larger obstacles than gene deletion.

I view this finding as a cautionary tale to reference any time a study comes out stating that A and B genes are found to cause X and Y symptoms or behavior. Researchers don’t have enough evidence in 2015 to unequivocally describe what rodent brains are capable of, much less human brains.

The researchers implied how they kept faith in their work with the phrase:

“The compensatory mechanism is imperfect and does not fully restore cGKII-dependent function.”

Is perfection the standard to which their research is also held?

http://www.pnas.org/content/112/10/3122.full “Network compensation of cyclic GMP-dependent protein kinase II knockout in the hippocampus by Ca2+-permeable AMPA receptors”