Neurons that fire together wire together

A memory trace in a living animal after it has encountered a single, new stimulus has been detected for the first time. The animal is of course the honeybee, and the memory is an odour.

Neuroscientists have looked into a living brain to explore short-term memory as never before. Roberto Fernández Galán, a leading author on the report and a postdoctoral research associate at Carnegie Mellon University explained:

“We are the first to observe this phenomenon at the network level. We are also the first to detect a distinct signature, not only of a sensory short-term memory, but one that developed after a single exposure to a previously unknown stimulus, so that there is no context. All previous studies in this field have observed only a sustained, non-specific increase in neural activity after a living animal is repeatedly exposed to a stimulus. These investigations haven't retrieved a signature of a stimulus, whereas we have.”

Their finding supports Hebb's theory of learning that

“neurons that fire together wire together,” thereby strengthening their connections. According to the theory, a stimulus activates some neurons while inhibiting others. Once this stimulus is removed, traces of that excitation/inhibition pattern -- so-called Hebbian reverberations -- should remain.