Early olfactory experience induces structural changes in the primary olfactory center of an insect brain.

ARENAS, ANDRÉS; GIURFA, MARTIN; SANDOZ, JEAN CHRISTOPH; HOURCADE, B; DEVAUD, JM; FARINA WM

EUROPEAN JOURNAL OF NEUROSCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2012 p. 682 - 690

0953-816X

The antennal lobe (AL) is the first olfactory center of the insect brain and is constituted of different functional units, the glomeruli. Inthe AL, odors are coded as spatiotemporal patterns of glomerular activity. In honeybees, olfactory learning during early adulthoodmodifies neural activity in the AL on a long-term scale and also enhances later memory retention. By means of behavioralexperiments, we first verified that olfactory learning between the fifth and eighth day of adulthood induces better retentionperformances at a late adult stage than the same experience acquired before or after this period. We checked that the specificity ofmemory for the odorants used was improved. We then studied whether such early olfactory learning also induces long-term structuralchanges in the AL consistent with the formation of long-term olfactory memories. We also measured the volume of 15 identifiedglomeruli in the ALs of 17-day-old honeybees that either experienced an odor associated with sucrose solution between the fifth andeighth day of adulthood or were left untreated. We found that early olfactory experience induces glomerulus-selective increases involume that were specific to the learned odor. By comparing our volumetric measures with calcium-imaging recordings from aprevious study, performed in 17-day-old bees subjected to the same treatment and experimental conditions, we found that glomerulithat showed structural changes after early learning were those that exhibited a significant increase in neural activity. Our results makeevident a correlation between structural and functional changes in the AL following early olfactory learning.