Can lost memories ever be ''found'' again?

Question

Can memories that were at one stage completely unreachable ever be retrieved again?
Also, I've heard of the terms "Memory loss'' and ''memory lack'', and how the two are different. What do the two terms mean, and how do they differ?

Please do not reply unless you work in the field/s of Psychology, Psychiatry or Neurology, or is undertaking tertiary study in one of the subjects.

Answer 1

It depends where you lost them. Seriously, memory storage involves the limbic system, and is affected by the amygdala, cyngulate gyrus, hippocampus, and mammillary bodies. How the brain accesses these memories is a little bit more difficult to understand, but these mentioned structures are involved because in certain pathalogical states (i.e. Wernicke-Kosakoff syndrome, Alzheimer's disease) these nuclei are affected and memory is impaired. I don't believe that memory loss from these pathologies can be regained. There is also the phenomenon of psychological memory loss which can be re-accessed. There are also different types of amnesia, some of which can be re-accessed and some cannot. Memory loss implies that the memory was there at one point but was subsequently lost (for a period of time or permanently). Memory lack implies that the memory was never formed although the event was witnessed. This second term implies a dysfunction in the mechanism that establishes memory in the first place. Such as neurosurgery or tumor that destroyed the part of the limbic system necessary to store the memory.