I watched the X-men movies and read some of the comics but I couldn't understand how he couldn't just regenerate his brain to get his memories? I thought things associated with his Nervous Systems could be the problem, but I want someone more scientific to help. And yes I read some of the other post and they did not explain in enough detail.
Unfortunately there is no real world or in-world logic that would explain it. While each continuity handles it differently, they all have the same result; whatever damage was done to erase Wolverine's memories is permanent and cannot be undone easily.
Earth-199999, the MCU, is the simplest, as it shows when, where and how Logan lost his memories. An adamantium bullet shot through the skull scrambled his brains. His implicit memories (behavior, language, skills) are intact, but explicit memories are lost. Except they are not. Professor X is able to find and tries to unlock those memories. And Logan remembers some memories from before (WW2 prisoner of war during Little Boy). So the memories are repressed or inaccessible through normal means.
Earth-616 is so very convoluted its hard to keep track of. Decades of comic history can do that. Wolverine regenerates from being flattened by a steamroller and complete nuclear annihilation without memory loss. Other people with the same powers also don't suffer from memory loss. Deadpool for one, regularly blows his own brains out or other cranial damage, and is good to go. His memory loss stems from constant cancer growths and healing power fixing it. In 616, Wolverine goes through memory conditioning and reprogramming in the Weapon X project. Brainwashed to become an assassin, and that's where he loses most of his memories. False memories implanted via fake scenes and actors. Very technical, practical applications. I've read there were also telepaths or psychics involved. The memories are there, just buried.
In the end, the reason the Wolverine in the movie can't regenerate his memories are because the movies stick to some basic tenants of the comic character. Comic Wolverine has no memories, so neither should Movie Wolverine. Any reason given has to take that into account. In real life, physical damage to memory cells completely disconnect those memories with 0% chance of recovery through modern science. Some physical trauma causes memory loss, while mental trauma can cause repression of memories as a survival instinct (shock), two different causes with the same result. Amnesia simply means Memory Loss after all.
He can regenerate brain tissue, but if the original memories 'written' on that brain tissue are gone, say through a gunshot wound, as in the X-Men: Origins film, then simply regenerating the tissue will not bring them back.
To use a metaphor: it's like burning a piece of paper. Wolverine's power enables him to re-grow that piece of paper, but any writing or drawings on it are irretrievable.
The answer is found in a story from Marvel called, "Origin". Wolverine was actually born James Howlett in late 19th century Alberta, Canada. But rather than go on through the twisted drama that actually lead to the manifestation of Wolverine's powers, we can use the aftermath to explain his memory loss. This was the first of many traumatic events Wolverine would find himself in, which afterwards he would start to have almost immediate amnesia.
Wolverine's mind treats traumatic memories as a psychic injury. Bringing back his memories would be the opposite of what his healing factor is trying to do, it would be like Wolverine's healing factor reopening wounds instead of closing them.
As a comparison, Sabretooth has a similar healing factor, but he's cruel and violent. His mind dances in unison with the rage, and therefore he doesn't believe anything he's done as traumatic. Thus, there is no need to "heal" his memories in the same way. Another comparison is Deadpool, who's healing factor is off the charts, but his mind is in constant flux because of it, which is often pointed as the reason for his "insanity/fourth wall breaking antics".
So no, there's no real life reason as to why Wolverine has memory loss. It's actually a tragic point that few talk about related to his healing factor.
Memories are like signals and if you have done something you have done before, your brain recreates those signals. If a well placed bullet lodges itself into Wolverines brain, then he would regenerate, but lose all his feelings and memories.