An interesting study providing more evidence for the computational theory of mind.
Confirming what neurocomputational theorists have long suspected, researchers report that the human brain locks down episodic memories in the hippocampus, committing each recollection to a distinct, distributed fraction of individual cells.
I think the part that’s most interesting about this study is this passage.
The researchers found that recently viewed words were stored in a distributed fashion throughout the hippocampus, with a small fraction of cells, about 2 percent, responding to any one word and a small fraction of words, about 3 percent, producing a strong change in firing in these cells.
“Intuitively, one might expect to find that any neuron that responds to one item from the list would also respond to the other items from the list, but our results did not look anything like that. The amazing thing about these counterintuitive findings is that they could not be more in line with what influential neurocomputational theorists long ago predicted must be true,” said Wixted.
Although only a small fraction of cells coded recent memory for any one word, the scientists said the absolute number of cells coding memory for each word was large nonetheless — on the order of hundreds of thousands at least. Thus, the loss of any one cell, they noted, would have a negligible impact on a person’s ability to remember specific words recently seen.
It’s pretty clear that something about those memories is being stored in the hippocampus. Of course, the hippocampus’s central role in memory has been known for a long time, since patient’s with damage there often have trouble making or retrieving memories, but seeing specific cells fire up gives more clues than ever before about what exactly is getting stored there.
From what I’ve read before, the hippocampus is probably more of a pointer table, a switchboard that stores the “addresses” of the memories of sensory impressions in each sense’s brain module, with sight memories being stored in the vision center, smell memories in the olfactory centers, etc. The hippocampus is probably responsible for recognizing a pattern currently being senses and pulling up previous patterns of sensory information, in other words, retrieving memories, and for recording the locations of the components of new memories.
The ongoing progress of neuroscience!