"This is the first time anyone has found a way to store information over seconds about both temporal sequences and stimulus patterns directly in brain tissue," says Dr. Strowbridge. "This paves the way for future research to identify the specific brain circuits that allow us to form short-term memories."
Their study, entitled "Mnemonic Representations of Transient Stimuli and Temporal Sequences in Rodent Hippocampus In Vitro," is slated for publication in the October issue of Nature Neuroscience, and is currently available online.
"The type of activity we triggered in isolated brain sections was similar to what other researchers have demonstrated in monkeys taught to perform short-term memory tasks," according to Mr. Hyde. "Both types of memory-related activity changes typically lasted for 5-10 seconds."
The researchers also demonstrated that they could generate memories for specific contexts, such as whether a particular pathway was activated alone or as part of a sequence of stimuli to different inputs. Changes in ongoing activity of hippocampal neurons accurately distinguished between two temporal sequences, akin to humans recognizing the difference between two different song melodies. The artificial memories Dr. Strowbridge's group created in the hippocampus continued to recognize each sequence even when the interval between stimuli was changed.