Scientists from Russia, Belgium and the US conducted a research to understand what professions  affect the physiological processes in the brain and reduce it.

As it turned out, the astronaut's brain suffers most as a result of work in the profession: they narrow the central furrow separating the frontal and parietal lobes, the bark of the big hemispheres shifts up the skull and disturbs the circulation of the cerebrospinal fluid in the parietal lobes, moreover, the longer the astronauts stay on the ISS, the more tangible are the listed changes.

A reversible decrease in the volume of gray matter in the temporal cortex by almost 3% have been noticed, as well as an irreversible decrease in the amount of white matter.

The taxi drivers have observed the opposite effect: during training, the hippocampus increases slightly. Perhaps this is due to the need to memorize many routes and detours.

But it is interesting that the use of the navigator starts the reverse process, since the gadget replaces the hippocampus, eliminating the need to simulate route options in your head.