When the RF exposure reaches a given level, they do this less often. Rats who have been trained to negotiate a maze lose the ability to do so when the RF exposure is high enough. The standards bodies have recognized these as undesirable effects and have set exposure limits to prevent them. Whether heating in the brain changes its function, or tissue heating disturbs the animals to the extent that they no longer want to perform their tasks, or if some other undefined mechanism has been responsible is not the issue. The primary goal of the standard limit is to prevent the effect regardless of its cause.
Some people ask about athermal effects.
That is a whole subject unto itself and is something that I will write about in more detail in future articles. However, don't forget that the standards were developed to prevent detectable changes in scientific test subjects. Mechanisms causing the changes are not considered in setting the limit, so if some of the observed changes were found to be caused by an athermal effect, they are also covered by the safety standards. RF bioeffects are real. Don't let any of your experiences convince you otherwise.