, 2007, Orban et al., 2004 and Passingham,
Romidepsin research buy 2009). One striking parallel in the memory signals seen across the monkey and human medial temporal lobe is significantly stronger responses to novel relative to familiar visual stimuli in the perirhinal cortex (Brown et al., 1987, Brozinsky et al., 2005, Fahy et al., 1993, Gonsalves et al., 2005, Henson et al., 2003, Köhler et al., 1998, Li et al., 1993 and Montaldi et al., 2006). Beyond this signal of relative stimulus novelty, however, the parallels between memory-related physiological signals in monkeys and humans are less striking. For example, in the monkey perirhinal cortex, Miller and Desimone (1994) reported stimulus-selective enhancement to a behaviorally relevant matching stimuli (match
enhancement) as well as stimulus-selective suppression to nonrelevant matching stimuli (match suppression) during a delayed match to sample task. Reports of match enhancement in the human perirhinal cortex, however, have been mixed (Dudukovic et al., 2011 and Duncan et al., 2009) although the tasks used in humans differed in numerous respects from the task used in monkeys. In the hippocampus, several human fMRI studies (Dudukovic et al., 2011 and Duncan et al., 2009) as well as a human single unit study in epileptic patients (Fried et al., 1997) FG 4592 reported strong match enhancement signals. By contrast, in the monkey hippocampus, several recent reports have described decrements but not enhancements in neural responses associated with repeated stimulus presentations (Jutras and Buffalo, 2010 and Yanike et al., 2009). Although many previous studies have mapped early visual areas in monkeys and humans performing the same perceptual task, few studies have compared medial
temporal lobe activity Ribonucleotide reductase across species as subjects perform the same memory task. One exception is Law et al. (2005), who developed a conditional motor associative learning task for humans based on one used in a previously published monkey physiology study (Wirth et al., 2003). Law et al. (2005) reported clear increases in the BOLD fMRI signals across the medial temporal lobe structures as human subjects learned new conditional motor associations. These findings appeared to parallel the single unit findings in the monkey hippocampus described by Wirth et al. (2003) that showed either increases or decreases in hippocampal single unit activity that were correlated with the animal’s learning curve. However, it remained unclear how the increases and decreases in single unit activity seen in individual monkey hippocampal cells corresponded to the global pattern of increased BOLD activity seen in humans.