Presumably memories are stored in the brain in some sort of chronological order so that we have a sense of when things occurred. Where in the brain are the oldest memories, how does the brain fill from there and does the process ever get muddled?

fosse4

Don't know about the first bit of your question but if you talk to my sisters (2 older, one younger) the memories are certainly muddled! (and haven't got any better with time despite photographic evidence that proves they are wrong!) May 27 04, 9:30 AM

McGruff

I have a sister like that too, John, and does she ever get hard-headed about stuff she doesn't remember correctly. She thinks our dad died on May 6th instead of May 3rd and none of us have been able to set her right, not even my mom. It's been 14 years, we gave up. My older sister, on the other hand, remembers things that happened to her as young as two, which I surely don't. I have vague memories of my fifth birthday and around that time, but little any earlier. She also remembers dates, not just the real important ones, but things like what day pets came into her household, and what day they died. I'm lucky if I can remember the year. The current year sometimes escapes me. Anyway, the region of the brain that stores and retrieves distant memories is known as the anterior cingulate cortex. The hippocampus processes recent memory, but it doesm't store memories permanently. The formation of new memories is thought to involve the strengthening of synaptic connections between groups of neurons. Remembering involves the reactivation of the same group or network of neurons. As memories age, the networks gradually change. Initially, memories for everyday life events appear to depend on networks in the region of the brain called the hippocampus, however over time these memories become increasingly dependent upon networks in the region of the brain called the cortex. Scientists believe there is active interaction between the hippocampus and cortex, and that the transfer process of memories between these two regions in the brain occurs over several weeks and likely during sleep. May 27 04, 10:49 AM

gmackematix

I'm not sure if my anterior cingulate cortex or my hippocampus was taking all that in, McG, but thanks for a nice mix of anecdote and science. May 28 04, 9:48 PM