Effect of articulatory suppression on task-switching performance: implications for models of working memory

In a series of experiments, we examine some effects of articulatory suppression in task switching. The results from Experiments 1a and 2a showed that switch costs in the articulatory suppression condition were larger than those in the control and tapping conditions when the switching cues were not provided. On the other hand, articulatory suppression did not have any effect on switch costs in Experiments 1b and 2b, where the switching cues were provided. In Experiment 3, using a computer-assisted experimentation, this pattern of data was replicated in a two-factor design with articulatory suppression and switching cues factors. The results indicate that a specific component in working memory, the phonological loop, might contribute to the performance in task switching, at least in situations where the external task cues were not available. The data reported here suggest that the phonological loop plays an important role in one of the executive control processes, and challenge the traditional idea that the slave systems are simply governed by the central executive in the working memory.     

Fos expression in CRF-containing neurons in the rat paraventricular nucleus after central administration of neuromedin U

We examined the effects of centrally administered neuromedin U (NMU) on corticotrophin-releasing factor (CRF)-containing neurons in the hypothalamic paraventricular nucleus (PVN) of rats, using double immunohistochemistry for CRF and Fos. Almost all CRF-containing neurons in the parvocellular divisions of the PVN expressed Fos-like immunoreactivity 90 min after intracerebroventricular administration of NMU (3 nmol/rat). This results suggest the possibility that central NMU may be involved in stress-induced activation of CRF-containing neurons in the PVN.     

When remembering the past suppresses memory for future actions

Remembering planned actions at the correct time in the future is an integral component of prospective cognition. Recent studies on future remembering have led to suggestions that prospective cognition might be based on past experience. To test this hypothesis, we focused on retrieval-induced forgetting (RIF), which usually indicates that remembering past events suppresses memory for related but different past events. The current study assessed RIF in two kinds of event-based prospective memory (PM) tasks using either focal or non-focal cues for ongoing tasks. Participants studied six members from each of eight taxonomic categories and then practiced recalling three of the six members from four of the eight categories using category-stem cues. This retrieval practice suppressed the detection of non-practiced members of the practiced categories during the PM task with non-focal cues (Experiment 1) but not with focal cues (Experiment 2). The results suggest that recall of certain items inhibits the function of the others as PM cues, but only if the PM task does not largely share its processing with the ongoing task.     

Lexical decomposition of complex Kanji characters in Japanese readers

Summary The study investigates the question whether during recognition of a complex Kanji character readers also access the meaning of opaque components of the character. The experiment used a speeded semantic-categorization task of two characters, in which readers were requested to decide whether two characters represented words related in meaning or not. The control pairs consisted of (a) graphically similar, but semantically unrelated, characters, and (b) a simple character and a complex character, of which the simple character was a component (part-whole relation), the two characters being again semantically unrelated. The critical pairs consisted of two characters unrelated in meaning, one of which contained an opaque component element related in meaning to the other character. A corresponding trial with English and its alphabetic system would be to ask a subject to decide whether boycott is related in meaning to girl or not. In this condition the subject is expected to give a No response, but if the pseudocomponent boy is activated, interference could occur. (If boy is recovered during recognition of the pseudocompound boycott, the appropriate No response for boycott-girl could become more difficult to take.) The result of the experiment indicated interference in all three conditions (graphically similar characters, part-whole related characters, and opaque-component related characters. Thus, in an analogous task with alphabetic material, it would be more difficult to say No about the existence of a semantic relation between (a) tree and free, (b) boy and boycott, and (c) boycott and girl. The last result can be interpreted as offering evidence for the activation of the opaque component upon recognition of the complex character.This account is somewhat oversimplified. It is not always easy to determine which is a radical in a complex character. A higher radical can in fact be a combination of a lower radical with the addition of one or more strokes.     

Electronic and structural properties of 3D Hopf-linked carbon allotrope: Hopfene

ABSTRACT

Electronic and structural properties of a 3D carbon allotrope made of Hopf-linked graphenes, which we call a Hopfene – a type of topological crystal, are examined by semi-empirical molecular-orbital and density-functional-theoretical methods, where band-structure analyses reveal very different properties from those of 2D graphenes. Furthermore, the analyses give an interesting finding that, depending on graphene-sheet spacings, Hopfenes exhibit different band features between primary-type Hopfene with a finite minimum sheet spacing and secondary type with its double-sized spacing. The primary type shows semi-metallic nature and the secondary type exhibits semi-metallic or semiconducting nature at different bands and also has flat bands; these conducting features can be utilised by Fermi-level control. A device application of Hopfenes is also provided.