The experiments were performed in the laboratory of Randolf Menzel, whose pioneering observational experiments in the 1970s and 1980s showed that honeybees exposed to an odor and rewarded with sugar could develop a memory of that odor and temporarily store it as "working memory." They also found that honeybees lost their working memory of a re-enforced odor if they were cooled down and then revived, suggesting that the memory wasn't permanently stored.
This latest study is the first to combine fluorescent dye imaging developed by Galizia, and advanced image processing and mathematical data analysis developed by Galán to actually detect a working memory trace.
In the current research, the scientists studied clusters of neurons called glomeruli within the honeybee's antennal lobe (AL), considered the invertebrate equivalent of the brain's olfactory bulb. Team member Marcel Weidert placed fluorescent probes within different glomeruli, and imaged their activity using dyes sensitive to the opening and closing of calcium channels on neurons. The scientists created an imaging grid across the glomeruli and measured the ratio of fluorescence versus nonfluorescence over time.
Galán then used advanced mathematical techniques to process the images and create a matrix of the extent (or amplitude) of neuronal excitation and inhibition within glomeruli. He retrieved a spatial pattern of synchronized, correlated activity ?the memory trace ?from what appeared to be random fluctuations of neural activity.
"The trace is like a fingerprint that disappears over time. It's
Source:Carnegie Mellon University