Supplementary materials for Yeshurun et al 2009: The Privileged Brain Representation of First Olfactory Associations: Yaara Yeshurun, Hadas Lapid, Yadin Dudai, Noam Sobel, The Privileged Brain Representation of First Olfactory Associations, Current Biology, Volume 19, Issue 21, 2009, Pages 1869-1874, ISSN 0960-9822, https://doi.org/10.1016/j.cub.2009.09.066. (http://www.sciencedirect.com/science/article/pii/S0960982209018570) Abstract: Summary Authors [1], poets [2], and scientists 3, 4, 5, 6 have been fascinated by the strength of childhood olfactory memories. Indeed, in long-term memory, the first odor-to-object association was stronger than subsequent associations of the same odor with other objects [7]. Here we tested the hypothesis that first odor associations enjoy a privileged brain representation. Because emotion impacts memory 8, 9, 10, we further asked whether the pleasantness of an odor would influence such a representation. On day 1, we associated the same visual objects initially with one, and subsequently with a second, set of pleasant and unpleasant olfactory and auditory stimuli. One week later, we presented the same visual objects and tested odor-associative memory concurrent with functional magnetic resonance brain imaging. We found that the power (% remembered) of early associations was enhanced when they were unpleasant, regardless of whether they were olfactory or auditory. Brain imaging, however, revealed a unique hippocampal activation for early olfactory but not auditory associations, regardless of whether they were pleasant or unpleasant. Activity within the hippocampus on day 1 predicted the olfactory but not auditory associations that would be remembered one week later. These findings confirmed the hypothesis of a privileged brain representation for first olfactory associations. Keywords: SYSNEURO