Although a complete novice in brain science, I have been curious. My question might appear to be similar to this previously asked question, but I believe I am addressing a different case.
The brain's storage capacity is said to be something closer to around 2.5 petabytes (a million GB).
An article on ScientificAmerican.Com says:
...neurons combine so that each one helps with many memories at a time, exponentially increasing the brain’s memory storage capacity to something closer to around 2.5 petabytes (or a million gigabytes). For comparison, if your brain worked like a digital video recorder in a television, 2.5 petabytes would be enough to hold three million hours of TV shows. You would have to leave the TV running continuously for more than 300 years to use up all that storage.
I think that's a lot of storage space, and someone like me may never utilize even 20 percent of it. But a vast portion of that storage space can get filled up over a long period of time if we indulge in a lot of study, research or learning, can't it?
In that case, is it possible that all or part of the information that has been acquired and stored gets jumbled and becomes irretrievable; or worse, irrational? I have never heard about such a case, but I am wondering if a brain malfunction like that can ever happen.