Does anyone know about this experiment?

Maybe you’re thinking about the seminal case of “H.M.” (Henry Gustav Molaison), who developed a seizure disorder following a bicycle accident at age 9. Surgeries then disabled a large portion of the brain structures involved in memory. A lot of what we know about memory and the brain structures that mediate it come from various studies on H.M. Here’s one that looked at how his motor memory continued unimpaired.

My sister is head injured and her short term memory was effected. What we’ve experienced is that she completely forgets about all the rote and mundane things in her life like scheduling dentist appointments, doctor’s appointments, when the dog was last fed etc. If something highly emotional happens like when our mother died she remembers that. I’ve concluded that, for her at least, memory is intrinsically tied to emotion.

Her ability to remember songs (different part of the brain), though, is unaffected.

I thought of H.M. too. His story continues to turn up in the literature again and again. Only a few nights ago I read a passage in this 2011 book (page 57) that referenced his case.

So would that mean that there are more than just anterograde and retrograde memory loss? That is, if there is another type of emotional memory?

Some of the works by Oliver Sacks discuss the memory phenomena.

1953 to be exact. “H.M.” (Henry Gustav Molaison) had a bike accident at 9 which may or may not have caused epilepsy with partial seizures. After age 16, the seizures worsened and at 26 (I think) a doctor at Harvard removed fairly substantial sections of his brain so the seizures would stop. This caused both anterograde amnesia, and retrograde amnesia. Anterograde amnesia is the loss of the ability to create new memories after the surgery leading to an inability to recall the recent past. Long-term memories from before the event remained intact. In retrograde amnesia, memories created prior to surgery or an accident or a stroke, are lost. His procedural memory, created through “procedural learning” or, repeating a complex activity over and over again until all of the relevant neural systems work together to automatically produce the activity, remained intact. Much of Procedural Memory involves motor tasks.

The bike accident and the epilepsy had nothing to do with amnesia (although any head injury has the potential for such.) It was a result of the surgery.

It would be most unusual for a brain “event” to cause amnesia years later. It happens right away.

If you folks want to read about the different kinds of memory, look up “Memory” in Wikipedia. You’ll find a pretty substantial explanation of various types of memory.

However, if you’re a slug, here are the Cliff notes…..
We can boil it down to three kinds:
Working Memory
Short-term Memory
Long-term Memory.

WM = holding onto an idea while working with another.
SM= what you ate for breakfast
LT= well, y’all know that already.

@thorninmud
That was a different case, where a 40 year old man who lost motor functioning after brain surgery regained it some 13 years later through memory training of brain structures lying dormant. The memory of the tasks came back but the speed of doing them lagged behind, supposedly due to the long elapsed period of time between the surgery and the training.