93,94 Strikingly, however,

at the 1-day delay, the details associated with negative simulations were remembered significantly less often than the details associated with positive and neutral simulations. We related this finding to previous studies that have documented a phenomenon known as “fading affect bias”: emotional Inhibitors,research,lifescience,medical reactions tend to fade more quickly over time for negative than positive everyday experiences.95 Perhaps rapid fading of negative affect over time rendered details associated with negative simulations more difficult to recall than those associated with positive or neutral simulations. Although additional research will be required to understand this finding, it may be related in interesting ways to the simulation of RG7204 manufacturer future events in clinical populations with affective disorders. A number of studies have shown that Inhibitors,research,lifescience,medical patients with depression96,97 and anxiety98,99 exhibit impaired simulations of future events that tend to lack specific detail and are often negatively biased. Inhibitors,research,lifescience,medical These observations, as well as related observations of impaired future simulations in other psychiatric and neurological disorders (for reviews, see refs 19,78), highlight the clinical relevance of research concerning imagining the future. They also suggest that it will be interesting to examine memory for positive and negative

simulations in depressed and anxious patients in order to determine whether patterns consistent with x201c;fading affect bias” — ie, impaired recall Inhibitors,research,lifescience,medical of negative simulations after a long delay versus a short delay — are absent or reduced in such patients. Distinguishing betwee true and false memories The observation that memory and imagination depend, at

least Inhibitors,research,lifescience,medical in part, on a common neural network, raises an important question: how does the brain distinguish between memories for actual past experiences and those that have only been imagined? One clue comes from the Addis et al86 study discussed earlier, in which participants were scanned while remembering actual events consisting of key person-place-object details, or imagining experiences comprised of recombined details from different memories. As in previous studies, the core Thymidine kinase network discussed earlier was activated for both remembering and imagining. In addition, however, Addis et al86 noted that distinct subsystems within the core network were preferentially associated with imagining and remembering, respectively. The imagining network consisted of medial temporal lobe including anterior hippocampus, bilateral medial prefrontal cortex, inferior frontal gyrus, polar and posterior temporal cortex, and medial parietal cortex. The remembering network included posterior visual cortices such as fusiform, lingual and occipital gyri and cuneus, as well as parahippocampal gyrus and posterior hippocampus.