bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective incorporation of influenza virus RNA segments into virions
Authors: Fujii Yutaka , Goto Hideo , Watanabe Tokiko , Yoshida Tetsuya , Kawaoka Yoshihiro
Published: February 2003

The genome of influenza A virus is comprised of eight viral RNA (vRNA) segments. Although the products of all eight vRNA segments must be present for viral replication, little is known about the mechanism(s) responsible for incorporation of these segments into virions. Two models have been proposed for the generation of infectious virions containing eight vRNA segments. The random-incorporation model assumes a common structural feature in all the vRNAs, enabling any combination of vRNAs to be incorporated randomly into virions. The selective-incorporation model predicts the presence of specific structures in each vRNA segment, leading to the incorporation of a set of eight vRNA segments into virions. Here we demonstrate that eight different vRNA segments must be present for efficient virion formation and that sequences within the coding region of (and thus unique to) the neuraminidase vRNA possess a signal that drives incorporation of this segment into virions. These findings indicate a unique contribution from individual vRNA segments and thus suggest a selective (rather than random) mechanism of vRNA recruitment into virions. The neuraminidase vRNA incorporation signal and others yet to be identified should provide attractive targets for the attenuation of influenza viruses in vaccine production and the design of new antiviral drugs.
The N-terminal domain of mammalian soluble epoxide hydrolase is a phosphatase
Authors: Cronin Annette , Mowbray Sherry , Dürk Heike , Homburg Shirli , Fleming Ingrid , Fisslthaler Beate , Oesch Franz , Arand Michael
Published: February 2003

The mammalian soluble epoxide hydrolase (sEH) is an enzyme with multiple functions, being implicated in detoxification of xenobiotic epoxides as well as in regulation of physiological processes such as blood pressure. The enzyme is a homodimer, in which each subunit is composed of two domains. The 35-kDa C-terminal domain has an α/β hydrolase fold and harbors the catalytic center for the EH activity. The 25-kDa N-terminal domain has a different α/β fold and belongs to the haloacid dehalogenase superfamily of enzymes. The catalytic properties of the enzyme reported so far can all be explained by the action of the C-terminal domain alone. The function of the N-terminal domain, other than in structural stabilization of the dimer, has therefore remained unclear. By structural comparison of this domain to other haloacid dehalogenase family members, we identified a putative active site containing all necessary components for phosphatase activity. Subsequently, we found rat sEH hydrolyzed 4-nitrophenyl phosphate with a rate constant of 0.8 s
−1
and a
K
m
of 0.24 mM. Recombinant human sEH lacking the C-terminal domain also displayed phosphatase activity. Presence of a phosphatase substrate did not affect epoxide turnover nor did epoxides affect dephosphorylation by the intact enzyme, indicating both catalytic sites act independently. The enzyme was unable to hydrolyze 4-nitrophenyl sulfate, suggesting its role in xenobiotic metabolism does not extend beyond phosphates. Thus, we propose this domain participates instead in the regulation of the physiological functions associated with sEH.
Mapping the binding interface between human eukaryotic initiation factors 1A and 5B: A new interaction between old partners
Authors: Marintchev Assen , Kolupaeva Victoria G. , Pestova Tatyana V. , Wagner Gerhard
Published: February 2003

The translation initiation factors (IFs) IF1/eIF1A and IF2/eIF5B have been conserved throughout all kingdoms. Although the central roles of the bacterial factors IF1 and IF2 were established long ago, the importance of their eukaryotic homologs, eukaryotic IFs (eIFs) eIF1A and eIF5B, has only recently become evident. The translation machinery in eukaryotes is more complex and accordingly, eIF1A and eIF5B seem to have acquired a number of new functions while also retaining many of the roles of bacterial IF1 and IF2. IF1 and IF2 have been shown to interact on the ribosome but no binding has been detected for the free factors. In contrast, yeast eIF1A and eIF5B have been reported to interact in the absence of ribosomes. Here, we have identified the binding interface between human eIF1A and the C-terminal domain of eIF5B by using solution NMR. That interaction interface involves the C termini of the two proteins, which are not present in bacterial IF1 and IF2. The interaction is, therefore, unique to eukaryotes. A structural model for the interaction of eIF1A and eIF5B in the context of the ribosome is presented. We propose that eIF1A and eIF5B simultaneously interact at two sites that are >50 Å apart: through their C termini as reported here, and through an interface previously identified in bacterial IF1 and IF2. The binding between the C termini of eIF1A and eIF5B has implications for eukaryote-specific mechanisms of recruitment and release of translation IFs from the ribosome.
Molecular bases of defective signal transduction in the platelet P2Y
12
receptor of a patient with congenital bleeding
Authors: Cattaneo Marco , Zighetti Maddalena L. , Lombardi Rossana , Martinez Constantino , Lecchi Anna , Conley Pamela B. , Ware Jerry , Ruggeri Zaverio M.
Published: February 2003

We have identified structural attributes required for signal transduction through a seven-transmembrane-domain receptor. Platelets from a patient (AC) with a congenital bleeding disorder had normal shape change but reduced and reversible aggregation in response to 4 μM ADP, similar to normal platelets with blocked P2Y
12
receptor. The response to 20 μM ADP, albeit still decreased, was more pronounced and was reduced by a P2Y
12
antagonist, indicating some residual receptor function. ADP failed to lower the adenylyl cyclase activity stimulated by prostaglandin E
1
in the patient's platelets, even though the number and affinity of 2-methylthioadenosine 5′-[
33
P]diphosphate-binding sites was normal. Analysis of the patient's P2Y
12
gene revealed a G-to-A transition in one allele, changing the codon for Arg-256 in the sixth transmembrane domain to Gln, and a C-to-T transition in the other allele, changing the codon for Arg-265 in the third extracellular loop to Trp. Neither mutation interfered with receptor surface expression but both altered function, since ADP inhibited the forskolin-induced increase of cAMP markedly less in cells transfected with either mutant P2Y
12
as compared with wild-type receptor. These studies delineate a region of P2Y
12
required for normal function after ADP binding.
Ethanol increases GABAergic transmission at both pre- and postsynaptic sites in rat central amygdala neurons
Authors: Roberto Marisa , Madamba Samuel G. , Moore Scott D. , Tallent Melanie K. , Siggins George R.
Published: February 2003

We examined the interaction of ethanol with the γ-aminobutyric acid (GABA)ergic system in neurons of slices of the rat central amygdala nucleus (CeA), a brain region thought to be critical for the reinforcing effects of ethanol. Brief superfusion of 11–66 mM ethanol significantly increased GABA type A (GABA
A
) receptor-mediated inhibitory postsynaptic potentials (IPSPs) and currents (IPSCs) in most CeA neurons, with a low apparent EC
50
of 20 mM. Acute superfusion of 44 mM ethanol increased the amplitude of evoked GABA
A
IPSPs and IPSCs in 70% of CeA neurons. The ethanol enhancement of IPSPs and IPSCs occurred to a similar extent in the presence of the GABA type B (GABA
B
) receptor antagonist CGP 55845A, suggesting that this receptor is not involved in the ethanol effect on CeA neurons. Ethanol superfusion also decreased paired-pulse facilitation of evoked GABA
A
IPSPs and IPSCs and always increased the frequency and sometimes the amplitude of spontaneous miniature GABA
A
IPSCs as well as responses to local GABA application, indicating both presynaptic and postsynaptic sites of action for ethanol. Thus, the CeA is the first brain region to reveal, without conditional treatments such as GABA
B
antagonists, consistent, low-dose ethanol enhancement of GABAergic transmission at both pre- and postsynaptic sites. These findings add further support to the contention that the ethanol–GABA interaction in CeA plays an important role in the reinforcing effects of ethanol.
Loading of the human 9-1-1 checkpoint complex onto DNA by the checkpoint clamp loader hRad17-replication factor C complex
in vitro
Authors: Bermudez Vladimir P. , Lindsey-Boltz Laura A. , Cesare Anthony J. , Maniwa Yoshimasa , Griffith Jack D. , Hurwitz Jerard , Sancar Aziz
Published: February 2003

The human DNA damage sensors, Rad17-replication factor C (Rad17-RFC) and the Rad9-Rad1-Hus1 (9-1-1) checkpoint complex, are thought to be involved in the early steps of the DNA damage checkpoint response. Rad17-RFC and the 9-1-1 complex have been shown to be structurally similar to the replication factors, RFC clamp loader and proliferating cell nuclear antigen polymerase clamp, respectively. Here, we demonstrate functional similarities between the replication and checkpoint clamp loader/DNA clamp pairs. When all eight subunits of the two checkpoint complexes are coexpressed in insect cells, a stable Rad17-RFC/9-1-1 checkpoint supercomplex forms
in vivo
and is readily purified. The two individually purified checkpoint complexes also form a supercomplex
in vitro
, which depends on ATP and is mediated by interactions between Rad17 and Rad9. Rad17-RFC binds to nicked circular, gapped, and primed DNA and recruits the 9-1-1 complex in an ATP-dependent manner. Electron microscopic analyses of the reaction products indicate that the 9-1-1 ring is clamped around the DNA.
Communication between neocortex and hippocampus during sleep in rodents
Authors: Sirota Anton , Csicsvari Jozsef , Buhl Derek , Buzsáki György
Published: February 2003

Both neocortical and hippocampal networks organize the firing patterns of their neurons by prominent oscillations during sleep, but the functional role of these rhythms is not well understood. Here, we show a robust correlation of neuronal discharges between the somatosensory cortex and hippocampus on both slow and fine time scales in the mouse and rat. Neuronal bursts in deep cortical layers, associated with sleep spindles and delta waves/slow rhythm, effectively triggered hippocampal discharges related to fast (ripple) oscillations. We hypothesize that oscillation-mediated temporal links coordinate specific information transfer between neocortical and hippocampal cell assemblies. Such a neocortical–hippocampal interplay may be important for memory consolidation.
Nicotine activates immature “silent” connections in the developing hippocampus
Authors: Maggi Laura , Le Magueresse Corentin , Changeux Jean-Pierre , Cherubini Enrico
Published: February 2003

In the hippocampus at birth, most glutamatergic synapses are immature and functionally “silent” either because the neurotransmitter is released in insufficient amount to activate low-affinity α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors or because the appropriate receptor system is missing or nonfunctional. Here we show that, in the newborn rat, a brief application of nicotine at immature Schaffer collateral-CA1 connections strongly enhances neurotransmitter release and converts presynaptically silent synapses into conductive ones. This effect is persistent and can be mimicked by endogenous acetylcholine released from cholinergic fibers. Thus, during a critical period of postnatal development, activation of nicotinic acetylcholine receptors contributes to the maturation of functional synaptic contacts and the wiring of adult hippocampal circuitry.
Tissue transglutaminase-induced aggregation of α-synuclein: Implications for Lewy body formation in Parkinson's disease and dementia with Lewy bodies
Authors: Junn Eunsung , Ronchetti Ruben D. , Quezado Martha M. , Kim Soo-Youl , Mouradian M. Maral
Published: February 2003

Proteinaceous aggregates containing α-synuclein represent a feature of neurodegenerative disorders such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Despite extensive research, the mechanisms underlying α-synuclein aggregation remain elusive. Previously, tissue transglutaminase (tTGase) was found to contribute to the generation of aggregates by cross-linking pathogenic substrate proteins in Huntington's and Alzheimer's diseases. In this article, the role of tTGase in the formation of α-synuclein aggregates was investigated. Purified tTGase catalyzed α-synuclein cross-linking, leading to the formation of high molecular weight aggregatesin vitro, and overexpression of tTGase resulted in the formation of detergent-insoluble α-synuclein aggregates in cellular models. Immunocytochemical studies demonstrated the presence of α-synuclein-positive cytoplasmic inclusions in 8% of tTGase-expressing cells. The formation of these aggregates was significantly augmented by the calcium ionophoreA23187and prevented by the inhibitor cystamine. Immunohistochemical studies on postmortem brain tissue confirmed the presence of transglutaminase-catalyzed ɛ(γ-glutamyl)lysine cross-links in the halo of Lewy bodies in Parkinson's disease and dementia with Lewy bodies, colocalizing with α-synuclein. These findings, taken together, suggest that tTGase activity leads to α-synuclein aggregation to form Lewy bodies and perhaps contributes to neurodegeneration.
Loss of WAVE-1 causes sensorimotor retardation and reduced learning and memory in mice
Authors: Soderling Scott H. , Langeberg Lorene K. , Soderling Jacquelyn A. , Davee Stephen M. , Simerly Richard , Raber Jacob , Scott John D.
Published: February 2003

The Scar/WAVE family of scaffolding proteins organize molecular networks that relay signals from the GTPase Rac to the actin cytoskeleton. The WAVE-1 isoform is a brain-specific protein expressed in variety of areas including the regions of the hippocampus and the Purkinje cells of the cerebellum. Targeted disruption of the WAVE-1 gene generated mice with reduced anxiety, sensorimotor retardation, and deficits in hippocampal-dependent learning and memory. These sensorimotor and cognitive deficits are analogous to the symptoms of patients with 3p-syndrome mental retardation who are haploinsufficient for WRP/MEGAP, a component of the WAVE-1 signaling network. Thus WAVE-1 is required for normal neural functioning.
Associative memory Hamiltonians for structure prediction without homology: α/β proteins
Authors: Hardin Corey , Eastwood Michael P. , Prentiss Michael C. , Luthey-Schulten Zadia , Wolynes Peter G.
Published: February 2003

We describe a method for predicting the structure of α/β class proteins in the absence of information from homologous structures. The method is based on an associative memory model for short to intermediate range in sequence contacts and a contact potential for long range in sequence contacts. The coefficients in the energy function are chosen to maximize the ratio of the folding temperature to the glass transition temperature. We use the resulting optimized model to predict the structure of three α/β protein domains ranging in length from 81 to 115 residues. The resulting predictions align with low rms deviations to large portions of the native state. We have also calculated the free energy as a function of similarity to the native state for one of these three domains, and we show that, as expected from the optimization criteria, the free energy surface resembles a rough funnel to the native state. Finally, we briefly demonstrate the effect of roughness in the energy landscape on the dynamics.
Binding of small molecules to an adaptive protein–protein interface
Authors: Arkin Michelle R. , Randal Mike , DeLano Warren L. , Hyde Jennifer , Luong Tinh N. , Oslob Johan D. , Raphael Darren R. , Taylor Lisa , Wang Jun , McDowell Robert S. , Wells James A. , Braisted Andrew C.
Published: February 2003

Understanding binding properties at protein–protein interfaces has been limited to structural and mutational analyses of natural binding partners or small peptides identified by phage display. Here, we present a high-resolution analysis of a nonpeptidyl small molecule, previously discovered by medicinal chemistry [Tilley, J. W.,

et al
.

(1997)
J. Am. Chem. Soc.
119, 7589–7590], which binds to the cytokine IL-2. The small molecule binds to the same site that binds the IL-2 α receptor and buries into a groove not seen in the free structure of IL-2. Comparison of the bound and several free structures shows this site to be composed of two subsites: one is rigid, and the other is highly adaptive. Thermodynamic data suggest the energy barriers between these conformations are low. The subsites were dissected by using a site-directed screening method called tethering, in which small fragments were captured by disulfide interchange with cysteines introduced into IL-2 around these subsites. X-ray structures with the tethered fragments show that the subsite-binding interactions are similar to those observed with the original small molecule. Moreover, the adaptive subsite tethered many more compounds than did the rigid one. Thus, the adaptive nature of a protein–protein interface provides sites for small molecules to bind and underscores the challenge of applying structure-based design strategies that cannot accurately predict a dynamic protein surface.
Repression of the HIV-1 5′ LTR promoter and inhibition of HIV-1 replication by using engineered zinc-finger transcription factors
Authors: Reynolds Lindsey , Ullman Christopher , Moore Michael , Isalan Mark , West Michelle J. , Clapham Paul , Klug Aaron , Choo Yen
Published: February 2003

Zinc finger domains are small DNA-binding modules that can be engineered to bind desired target sequences. Functional transcription factors can be made from these DNA-binding modules, by fusion with an appropriate effector domain. In this study, eight three-zinc-finger proteins (ZFPs) that bound HIV-1 sequences
in vitro
were engineered into transcription repressors by linking them to the Krüppel-associated box (KRAB) repressor domain (KOX1). One protein, ZFP HIVB-KOX, which bound to a 9-bp region overlapping two Sp1 sites, was found to repress a Tat-activated 5′ LTR cellular HIV-reporter assay to almost basal levels. A related six-finger protein, HIVBA′-KOX, was made to target all three Sp1 sites in the 5′ LTR promoter and efficiently inhibited both basal and Tat-activated transcription in unstimulated and mitogen-stimulated T cells. In contrast, a combination of two unlinked three-finger ZFPs, HIVA′-KOX and HIVB-KOX, which bind over the same region of DNA, resulted in less effective repression. Finally, HIVBA′-KOX was tested for its capacity to block viral replication in a cellular infection assay using the HIV-1 HXB2 strain. This ZFP was found to inhibit HIV-1 replication by 75% compared with control constructs, thus demonstrating the potential of this approach for antiviral therapy.
Inhibition of herpes simplex virus 1 gene expression by designer zinc-finger transcription factors
Authors: Papworth Monika , Moore Michael , Isalan Mark , Minczuk Michal , Choo Yen , Klug Aaron
Published: February 2003

The herpes simplex virus 1 (HSV-1) replicative cycle begins by binding of the viral activator, VP16, to a set of sequences in the immediate-early (IE) gene promoters. With the aim of inhibiting this cycle, we have constructed a number of synthetic zinc-finger DNA-binding peptides by using recently reported methods. Peptides containing either three or six fingers, targeted to a viral promoter, were engineered as fusions with a KOX-1 transcription repression domain. These proteins bound to the HSV-1 IE175k (ICP4) promoter,
in vitro
, with nanomolar or subnanomolar binding affinity. However, in a chloramphenicol acetyltransferase reporter system, only the six-finger protein was found to repress VP16-activated transcription significantly. Thus the longer array of zinc fingers is required to compete successfully against VP16, one of the most powerful natural activators known. We found that the HSV-1 replication cycle can be partially repressed by the six-finger peptide with the viral titer reduced by 90%.
Tadpole skin dies autonomously in response to thyroid hormone at metamorphosis
Authors: Schreiber Alexander M. , Brown Donald D.
Published: February 2003

Transgenic tadpoles that express a dominant negative thyroid hormone (TH) receptor specifically in their skin undergo normal metamorphosis, with one exception: they retain a larval epidermis over the developing adult epithelium. TH-induced death of the tadpole epidermis is inhibited by the dominant negative TH receptor whereas the TH-induced response of the neighboring fibroblasts and the cells that form the adult skin occur normally. Therefore death of the tadpole skin is a direct and cell autonomous target of TH, and its protection has no detectable influence on TH-induced changes of other cell types.
Drosophila
DEG/ENaC pickpocket genes are expressed in the tracheal system, where they may be involved in liquid clearance
Authors: Liu Lei , Johnson Wayne A. , Welsh Michael J.
Published: February 2003

The
Drosophila
tracheal system and mammalian airways are branching networks of tubular epithelia that deliver oxygen to the organism. In mammals, the epithelial Na
+
channel (ENaC) helps clear liquid from airways at the time of birth and removes liquid from the airspaces in adults. We tested the hypothesis that related
Drosophila
degenerin (DEG)/ENaC family members might play a similar role in the fly. Among 16
Drosophila
DEG/ENaC genes, called pickpocket (PPK) genes, we found 9 expressed in the tracheal system. By
in situ
hybridization, expression appeared in late-stage embryos after tracheal tube formation, with individual PPK genes showing distinct temporal and spatial expression patterns as development progressed. Promoters for several PPK genes drove reporter gene expression in the larval and adult tracheal systems. Adding the DEG/ENaC channel blocker amiloride to the medium inhibited liquid clearance from the trachea of first instar larvae. Moreover, when RNA interference was used to silence PPK4 and PPK11, larvae failed to clear tracheal liquid. These data suggest substantial molecular diversity of DEG/ENaC channel expression in the
Drosophila
tracheal system where the PPK proteins likely play a role in Na
+
absorption. Extensive similarities between
Drosophila
and mammalian airways offer opportunities for genetic studies that may decipher further the structure and function of DEG/ENaC proteins and development of the airways.
Experimental test of a method for determining causal connectivities of species in reactions
Authors: Torralba Antonio S. , Yu Kristine , Shen Peidong , Oefner Peter J. , Ross John
Published: February 2003

Theoretical analysis has shown the possibility of determining causal connectivities of reacting species and the reaction mechanism in complex chemical and biochemical reaction systems by applying pulse changes of concentrations of one or more species, of arbitrary magnitude, and measuring the temporal response of as many species as possible. This method, limited to measured and pulsed species, is given here an experimental test on a part of glycolysis including the sequence of reactions from glucose to fructose 1,6-biphosphate, followed by the bifurcation of that sequence into two branches, one ending in glycerol 3-phosphate, the other in glyceraldehyde 3-phosphate. Pulses of concentrations of one species at a time are applied to the open system in a non-equilibrium stationary state, and the temporal responses in concentrations of six metabolites are measured by capillary zone electrophoresis. From the results of these measurements and the use of the theory for their interpretation, we establish the causal connectivities of the metabolites and thus the reaction mechanism, including the bifurcation of one chain of reactions into two. In this test case of the pulse method, no prior knowledge was assumed of the biochemistry of this system. We conclude that the pulse method is relatively simple and effective in determining reaction mechanisms in complex systems, including reactants, products, intermediates, and catalysts and their effectors. The method is likely to be useful for substantially more complex systems.
Effects of C-terminal deletions on cystic fibrosis transmembrane conductance regulator function in cystic fibrosis airway epithelia
Authors: Ostedgaard Lynda S. , Randak Christoph , Rokhlina Tatiana , Karp Philip , Vermeer Daniel , Ashbourne Excoffon Katherine J. , Welsh Michael J.
Published: February 2003

To better understand the function of the conserved C terminus of the cystic fibrosis (CF) transmembrane conductance regulator, we studied constructs containing deletions in the C-terminal tail. When expressed in well differentiated CF airway epithelia, each construct localized predominantly to the apical membrane and generated transepithelial Cl
−
current. The results suggested that neither the C-terminal
P
SD-95/
D
iscs-large/
Z
O-1 (PDZ)-interacting motif nor other C-terminal sequences were absolutely required for apical expression in airway epithelia. Surprisingly, deleting an acidic cluster near the C terminus reduced both channel opening rate and transepithelial Cl
−
transport, indicating that it influences channel gating. These results may help explain the relative paucity of CF-associated mutations in the C terminus.
The Stakeholder Dimension in Information Systems Evaluation
Authors: Mcaulay Laurie , Doherty Neil , Keval Natasha
Published: February 2003

This study used an earlier critique of the cultural sciences for exploring the ideological basis for the evaluation of outsourcing. Questionnaire and interview responses are presented. These incorporate a range of evaluative criteria, which together represent an indicative list of the benefits and risks of outsourcing. The paper initially suggests that different stakeholders might be impacted on in different ways by benefits and risks. It is suggested that information technology outsourcing evaluation might thus be partial and not neutral in its impact on stakeholders. However, the differences and similarities between stakeholders suggest a subtle interplay of ideological concerns that does not totally deny the interests of all but the dominant stakeholders. Although the evaluation may be partial this does not deny the potential for those who might be presumed to be disadvantaged for making personal gains. However, in making personal gains, an ideology based on economic interests is furthered, thus occluding the opportunity for autonomous and responsible engagement with the process of evaluation.
The Critical Theory of Herman Dooyeweerd?
Authors: Basden Andrew
Published: February 2003

Jürgen Habermas is a wide-ranging thinker whose ideas have formed the philosophic foundation of critical systems thinking (CST). But can the Critical approach incorporate ideas from other thinkers without abandoning its Habermasian roots? The danger of adding ideas piecemeal to address specific difficulties in CST is that the whole will eventually collapse because of inconsistencies. So if we wish to import ideas from other thinkers we need to understand the points of agreement and disagreement with critical theory. This requires reference to a set of criteria, though not necessarily in any rigid way. This paper applies a set of criteria to a philosophic framework of ideas (that of the Dutch philosopher Herman Dooyeweerd) in order not to ‘score’ the ideas for Criticality, but rather to understand the process of bringing the ideas of a thinker from a different tradition to bear on the Critical approach in a commensurable way.
Functional Representation of 3d Space in Endogenous Attention Shifts
Authors: Couyoumdjian Alessandro , Di Nocera Francesco , Ferlazzo Fabio
Published: February 2003

The aim of this study was to explore whether the attentional system, as far as an endogenous orienting is concerned, allocates resources along the sagittal plane and whether such a process is affected by, and is likely to be based on, different functional representations of 3D space in the brain. Several models make a main action-based distinction between representations of peripersonal space and of those extrapersonal space. Accordingly, if attention has to move from one representation to another, it should be possible to observe a decrease in performance during such a transition. To test this hypothesis three experiments were run in which participants performed a cued detection task. Cue stimuli were informative and were centrally located around the fixation point. Target stimuli were displayed at four different depth planes. In the first experiment, assuming that the border between the peripersonal space and the extrapersonal space was at 1 m from the observer, half the target stimuli were located in the peripersonal space and half in the extrapersonal space. The fixation point was located at 1 m from the observer. In the second experiment, the fixation point was moved at 2 m from the observer in order to rule out the possible effects of ocular motor programming. In the third experiment, in order to rule out effects related to the spatial layout of target stimuli (i.e., centre of mass effect) two target stimuli were located in the peripersonal space and six in the extrapersonal space. In all the experiments, besides a validity effect, we observed greater reaction times when attention shift was across spatial representations than when it was within the same representation. The implications for action-oriented models of attention are discussed.
Belief Bias and Relational Reasoning
Authors: Roberts Maxwell J. , Sykes Elizabeth D.A.
Published: February 2003

When people evaluate categorical syllogisms, they tend to reject unbelievable conclusions and accept believable ones irrespective of their validity. Typically, this effect is particularly marked for invalid conclusions that are possible, but do not necessarily follow, given the premises. However, smaller believability effects can also be detected for other types of conclusion. Three experiments are reported here, in which an attempt was made to determine whether belief bias effects can manifest themselves on the relational inference task. Subjects evaluated the validity of conclusions such as William the Conqueror was king after the Pyramids were built (temporal task) or Manchester is north of Bournemouth (spatial task) with respect to their premises. All of the major findings for equivalent categorical syllogism tasks were replicated. However, the overall size of the main effect of believability appears to be related to task presentation, a phenomenon not previously identified for categorical syllogisms and which current theories of belief bias have difficulty explaining.
Phonological Information in Immediate and Delayed Sentence Recall
Authors: Rummer Ralf , Engelkamp Johannes
Published: February 2003

Potter and Lombardi (1990) state in their conceptual regeneration hypothesis that immediate sentence recall is only based on conceptual and lexical information; phonological information does not contribute. As experimental evidence for this hypothesis, they reported that if a sentence is followed by a word list that included a lure word similar to one of the content words of the sentence (target word), the lure word frequently intrudes into sentence recall. We demonstrated that Potter and Lombardi did not observe any influence of phonological information because list presentation followed sentence presentation, and phonological information was discarded. We observed that phonological information influenced the intrusion rate if recall was not delayed by the subsequent presentation of a word list. With immediate recall, the lure intrusion effect disappeared in auditorily presented sentences. This shows that, if available, phonological information contributes to sentence recall.
On the Nature of Insight Solutions: Evidence from Skill Differences in Anagram Solution
Authors: Novick Laura R. , Sherman Steven J.
Published: February 2003

According to the Gestalt psychologists, problem solutions that pop into mind suddenly with no awareness of the process by which they were generated are objectively as well as subjectively sudden. Thus, such pop-out solutions are qualitatively different from search solutions, which are constructed incrementally. The authors tested this claim in the domain of anagram solution. Experiment 1 documented that anagrams yield pop-out solutions, especially among highly skilled solvers. The results of Experiment 2 indicated that both pop-out and search solutions depended on the gradual accumulation of partial information, contrary to the Gestalt view of problem solving. Nevertheless, some aspects of the Experiment 2 results, as well as new analyses of an anagram study reported elsewhere, suggest that there may in fact be a qualitative difference between pop-out and search solutions. In particular, pop-out solutions may result from parallel processing of the constraints on the rearranged order of the anagram letters, whereas search solutions may result from a serial hypothesis-testing procedure.
Measuring Learning using an Untrained Control Group: Comment on R. Reber and Perruchet
Authors: Dienes Zoltán , Altmann Gerry
Published: February 2003

R. Reber and Perruchet (this issue) argue that use of control groups without training is unsound for establishing that learning has occurred. We show that inferring learning from a difference between a trained group and an untrained control in no way relies on their implausible additivity assumption, and that untrained control groups can be an invaluable aid to the researcher.
Why Untrained Control Groups Provide Invalid Baselines: A Reply to Dienes and Altmann
Authors: Perruchet Pierre , Reber Rolf
Published: February 2003

Dienes and Altmann argue that an untrained control group provides a reliable baseline to measure artificial grammar learning. In this reply, we first provide a fictitious example to demonstrate that this assessment is faulty. We then analyse why this assessment is wrong, and we reiterate the solution proposed in Reber and Perruchet (this issue) for a proper control. Finally, we point out the importance of these methodological principles in the context of implicit learning studies.
An Investigation of Phonology and Orthography in Spoken-Word Recognition
Authors: Slowiaczek Louisa M. , Soltano Emily G. , Wieting Shani J. , Bishop Karyn L.
Published: February 2003

The possible influence of initial phonological and/or orthographic information on spoken-word processing was examined in six experiments modelled after and extending the work Jakimik, Cole, and Rudnicky (1985). Following Jakimik et al., Experiment 1 used polysyllabic primes with monosyllabic targets (e.g., BUCKLE—BUCK / b ^ k @ l /—/ b ^ k /; MYSTERY—MISS, / m I s t 2 r i /—/ m I s /). Experiments 2, 3, and 4 used polysyllabic primes and polysyllabic targets whose initial syllables shared phonological information (e.g., NUISANCE—NOODLE, / n u s I n s /—/ n u d @ l /), orthographic information (e.g., RATIO—RATIFY, /r e Si o /—/ r æ t I f a I /), both (e.g., FUNNEL—FUNNY, / f ^ n @ l /—/ f ^ n i /), or were unrelated (e.g., SERMON—NOODLE, / s Å m @ n /—/ n u d @ l /). Participants engaged in a lexical decision (Experiments 1, 3, and 4) or a shadowing (Experiment 2) task with a single-trial (Experiments 2 and 3) or subsequent-trial (Experiments 1 and 4) priming procedure. Experiment 5 tested primes and targets that varied in the number of shared graphemes while holding shared phonemes constant at one. Experiment 6 used the procedures of Experiment 2 but a low proportion of related trials. Results revealed that response times were facilitated for prime—target pairs that shared initial phonological and orthographic information. These results were confirmed under conditions when strategic processing was greatly reduced suggesting that phonological and orthographic information is automatically activated during spoken-word processing.
Effects of Response Eccentricity and Relative Position on Orthogonal Stimulus—Response Compatibility with Joystick and Keypress Responses
Authors: Proctor Robert W. , Cho Yang Seok
Published: February 2003

When unimanual left—right movement responses are made to up—down stimuli, performance is better with the up—right/down—left mapping when responding in the right hemispace and with the up—left/down—right mapping when responding in the left hemispace. We evaluated whether this response eccentricity effect is explained best in terms of rotational properties of the hand (the end-state comfort hypothesis) or asymmetric coding of the stimulus and response alternatives (the salient features coding hypothesis). Experiment 1 showed that bimanual keypresses yield a response eccentricity effect similar to that obtained with unimanual movement responses. In Experiment 2, an inactive response apparatus was placed to the left or right of the active response apparatus to provide a referent. For half of the participants, the active and inactive apparatuses were joysticks, and for half they were response boxes with keys. For both response types, an up—right/down—left advantage was evident when the relative position of the active response apparatus was right but not when it was left. That bimanual keypresses yield similar eccentricity and relative location effects to those for unimanual movements is predicted by the salient features coding perspective but not by the end-state comfort hypothesis.
Reduced Timing Variability during Bimanual Coupling: A Role for Sensory Information
Authors: Drewing Knut , Aschersleben Gisa
Published: February 2003

On a repetitive tapping task, the within-hand variability of intertap intervals is reduced when participants tap with two hands as compared to one-hand tapping. Because this bimanual advantage can be attributed to timer variance (Wing—Kristofferson model, 1973a, b), separate timers have been proposed for each hand, whose outputs are then averaged (Helmuth & Ivry, 1996). An alternative notion is that action timing is based on its sensory reafferences (Aschersleben & Prinz, 1995; Prinz, 1990). The bimanual advantage is then due to increased sensory reafference. We studied bimanual tapping with the continuation paradigm. Participants first synchronized their taps with a metronome and then continued without the pacing signal. Experiment 1 replicated the bimanual advantage. Experiment 2 examined the influence of additional sensory reafferences. Results showed a reduction of timer variance for both uni- and bimanual tapping when auditory feedback was added to each tap. Experiment 3 showed that the bimanual advantage decreased when auditory feedback was removed from taps with the left hand. Results indicate that the sensory reafferences of both hands are used and integrated into timing. This is consistent with the assumption that the bimanual advantage is at least partly due to the increase in sensory reafference. A reformulation of the Wing—Kristofferson model is proposed to explain these results, in which the timer provides action goals in terms of sensory reafferences.
The Impact of Different Directed Forgetting Instructions on Implicit and Explicit Memory: New Evidence from a Modified process Dissociation Procedure
Authors: David Daniel , Brown Richard J.
Published: February 2003

In contrast to previous research on directed forgetting, the present studies adopted a recent modification of the process dissociation procedure (Jacoby, 1991; Richardson-Klavehn & Gardiner, 1995) to accommodate the cross-contamination of memory test performance by implicit and explicit memorial factors. In Experiment 1, 120 subjects were compared in global directed forgetting, item-by-item directed forgetting, and control conditions on estimates of voluntary conscious memory, involuntary conscious memory, and involuntary unconscious memory performance. In Experiment 2, 80 subjects were compared in specific directed forgetting and control conditions on estimates of voluntary conscious memory, involuntary conscious memory, and involuntary unconscious memory performance. Subjects showed significant decrements in voluntary and involuntary conscious memory performance following instructions for directed forgetting in all conditions. None of the directed forgetting conditions showed a decrement in involuntary unconscious memory performance. Results suggest that, regardless of instruction type, directed forgetting prevents the conscious expression of memorial information (both voluntary and involuntary) while leaving unconscious memory intact.
Causal Judgement as Evaluation of Evidence: The use of Confirmatory and Disconfirmatory Information
Authors: White Peter A.
Published: February 2003

There are four kinds of contingency information: occurrences and nonoccurrences of an effect in the presence and absence of a cause. In two experiments participants made judgements about sets of stimulus materials in which one of these four kinds had zero frequency. The experiments tested two kinds of predictions derived from the evidential evaluation model of causal judgement, which postulates that causal judgement depends on the proportion of instances evaluated as confirmatory for the cause being judged. The model predicts significant effects of manipulating the frequency of one kind of contingency information in the absence of changes in the objective contingency. The model also predicts that extra weight will be given to one kind of confirmatory information when the other kind has zero frequency, and to one kind of disconfirmatory information when the other kind has zero frequency. Results supported both sets of predictions, and also disconfirmed predictions of the power probabilistic contrast theory of causal judgement. This research therefore favours an account of causal judgement in which contingency information is transformed into evidence, and judgement is based on the net confirmatory or disconfirmatory value of the evidence.
The Relative Efficacy of Different forms of Knowledge of Results for the Learning of a New Relative Timing Pattern
Authors: De Jaeger Dominique , Proteau Luc
Published: February 2003

The goal of the present study was to determine the relative efficacy of verbal and auditory knowledge of results for promoting learning of a new constrained relative timing pattern. In a series of four experiments we compared the efficiency of verbal knowledge of results to that of auditory knowledge of results. The results of all four experiments revealed that verbal knowledge of result is a very effective source of information to promote learning of a new imposed relative timing pattern. Auditory knowledge of results favoured learning of a new relative timing pattern in a very limited set of circumstances. In the present study, this was only the case when movement velocity remained constant from one segment of the task to the next and if it resulted in an unfamiliar temporal pattern. The results of all four experiments also provided evidence that movement parameterization and relative timing are independent processes that can be developed in parallel.
Creativity and Inductive Reasoning: The Relationship between Divergent Thinking and Performance on Wason's 2—4—6 Task
Authors: Vartanian Oshin , Martindale Colin , Kwiatkowski Jonna
Published: February 2003

This study was an investigation of the relationship between potential creativity—as measured by fluency scores on the Alternate Uses Test—and performance on Wason's 2—4—6 task. As hypothesized, participants who were successful in discovering the rule had significantly higher fluency scores. Successful participants also generated higher frequencies of confirmatory and disconfirmatory hypotheses, but a multiple regression analysis using the stepwise method revealed that the frequency of generating disconfirmatory hypotheses and fluency scores were the only two significant factors in task outcome. The results also supported earlier studies where disconfirmation was shown to play a more important role in the later stages of hypothesis testing. This was especially true of successful participants, who employed a higher frequency of disconfirmatory hypotheses after receiving feedback on the first announcement. These results imply that successful participants benefited from the provision of feedback on the first announcement by switching to a more successful strategy in the hypothesis-testing sequence.
Retrieval Independence in Successive Recognition Tasks
Authors: Glass Arnold L. , Lian Arild , Helstrup Tore
Published: February 2003

In three experiments participants studied AB word pairs and completed two recognition tests. In the first recognition test, which was included in all three experiments, the B word had to be discriminated from two distractors that did not appear on the study list. In Experiment 1, in the second recognition test, an AB target was compared with distractors composed of words not on the study list. In Experiment 2, in the second recognition test, an AB target had to be discriminated from two other pairs that were created by randomly re-pairing A and B words that appeared on the study list. In Experiment 3, on the second recognition test, words from the study list were systematically re-paired to form distractors that contained either the same A term or the same B term as the target pair. Recognition of the B word on the first test was always at least partly independent of recognition of the AB pair on the second test. Even when recognition judgements were restricted to those for which the participants were most confident, all experiments demonstrated significant retrieval independence between the two tests.
The Influence of Response—Effect Compatibility in a Serial Reaction Time Task
Authors: Stöcker Christian , Sebald Albrecht , Hoffmann Joachim
Published: February 2003

Participants performed a serial reaction time task, responding to either asterisks presented at varying screen locations or centrally presented letters. Stimulus presentation followed a fixed second-order conditional sequence. Each keypress in the experimental groups produced a contingent, key-specific tone effect. The critical variation concerned the mapping of tones to keys. In Experiment 1, keypresses in one control condition produced noncontingent tone effects, while in another control condition there were no tone effects. In Experiment 2, three different key—tone mappings were compared to a control condition without tone effects. The results show that tone effects improve serial learning when they are mapped to the response keys contingently and in a highly compatible manner. The results are discussed with reference to an ideomotor mechanism of motor sequence acquisition.
Age of Acquisition, Ageing, and Verb Production: Normative and Experimental Data
Authors: Morrison Catriona M. , Hirsh Katherine W. , Duggan Geoffrey B.
Published: February 2003

Young and old adults were shown pictured or written verbs and asked to name them as quickly as possible. Simultaneous multiple regression was used to investigate which of a set of potential variables predicted naming speed. Age of acquisition was found to be an important predictor of naming speed in both young and old adults, and for both word and picture naming. Word frequency predicted picture-naming speed only in older adults and failed to make any significant contribution to word-naming speeds for either group of participants. The respective loci and roles of age of acquisition and frequency in lexical processing are discussed in the light of these findings.