Memory recall in arousing situations – an emotional von Restorff effect?

BACKGROUND: Previous research has demonstrated a relationship between memory recall and P300 amplitude in list learning tasks, but the variables mediating this P300-recall relationship are not well understood. In the present study, subjects were required to recall items from lists consisting of 12 words, which were presented in front of pictures taken from the IAPS collection. One word per list is made distinct either by font color or by a highly arousing background IAPS picture. This isolation procedure was first used by von Restorff. Brain potentials were recorded during list presentation. RESULTS: Recall performance was enhanced for color but not for emotional isolates. Event-related brain potentials (ERP) showed a more positive P300-component for recalled non-isolated words and color-isolated words, compared to the respective non-remembered words, but not for words isolated by arousing background. CONCLUSION: Our findings indicate that it is crucial to take emotional mediator variables into account, when using the P300 to predict later recall. Highly arousing environments might force the cognitive system to interrupt rehearsal processes in working memory, which might benefit transfer into other, more stable memory systems. The impact of attention-capturing properties of arousing background stimuli is also discussed

Anisotropic Josephson effects in point contacts between the heavy fermion superconductor URu₂Si₂ and Nb

Point contacts between the heavy-fermion superconductor URu(2)S(i)2 and Nb are studied. A finite de Josephson current is found in contacts aligned parallel to the a-b directions of URu2Si2 whereas it is absent in contacts aligned along the c direction. We attribute this extreme anisotropy; of the Josephson current to an unconventional superconducting order parameter in URu2Si2, with a symmetry leading to destructive interference for Josephson currents along the c direction