bluuebunny/crossref_metadata_2025 huggingface dataset:
Short‐term constant light potentiation of large‐magnitude circadian phase shifts induced by 8‐OH‐DPAT: effects on serotonin receptors and gene expression in the hamster suprachiasmatic nucleus
Authors: Duncan Marilyn J. , Franklin Kathleen M. , Davis Verda A. , Grossman Gregory H. , Knoch Megan E. , Glass J. David
Published: November 2005

Nonphotic phase‐shifting of mammalian circadian rhythms is thought to be mediated in part by serotonin (5‐HT) acting in the suprachiasmatic nucleus (SCN) circadian clock. Previously we showed that brief (1–3 days) exposure to constant light (LL) greatly potentiates nonphotic phase‐shifting induced by the 5‐HT agonist, (±)2‐dipropyl‐amino‐8‐hydroxyl‐1,2,3,4‐tetrahydronapthalene (8‐OH‐DPAT). Here we investigated potential mechanisms for this action of LL, including 5‐HT receptor upregulation and SCN clock gene and neuropeptide gene expression. Autoradiographic analysis of ritanserin inhibition of [3H]8‐OH‐DPAT binding indicated that LL (∼2 days) did not affect 5‐HT7 receptor binding in the SCN or dorsal raphe. Measurement of 5‐HT1A autoreceptors in the median raphe and 5‐HT1B receptors in the SCN also showed no effect of LL. In experiment 2, hamsters held under a 14‐h light : 10‐h dark photocycle (LD) or exposed to LL for ∼2 days received an intraperitoneal injection of 8‐OH‐DPAT or vehicle at zeitgeber time (ZT) 6 or 0 and were killed after 2 h of dark exposure. 8‐OH‐DPAT suppressed SCN Per1 and Per2 mRNAs at both ZTs, as assessed by in situ hybridization. Per1 mRNA was also suppressed by LL alone. In addition, in situ hybridization of arginine vasopressin (AVP) mRNA and vasoactive intestinal polypeptide mRNA showed that LL significantly suppressed the former but not the latter. The LL‐induced suppression of SCN Per1 mRNA and AVP mRNA may be involved in LL‐induced potentiation of pacemaker resetting, especially as these data provide additional evidence that LL suppresses circadian pacemaker amplitude, thus rendering the clock more susceptible to phase‐shifting stimuli.
Species and strain differences in the expression of a novel glutamate‐modulating cannabinoid receptor in the rodent hippocampus
Authors: Hoffman Alexander F. , Macgill Alice M. , Smith Dennison , Oz Murat , Lupica Carl R.
Published: November 2005

A novel, non‐CB1 cannabinoid receptor has been defined by the persistence of inhibition of glutamatergic EPSPs by the cannabinoid receptor agonist WIN55,212‐2 in mice lacking the cloned CB1 receptor (CB1–/–) (Hajos et al., 2001). This novel receptor was also distinguished from CB1 by its sensitivity to the antagonist SR141716A and its insensitivity to the antagonist AM251 (Hajos & Freund, 2002). We have chosen to refer to this putative receptor as CBsc due to its identification on Schaffer collateral axon terminals in the hippocampus. We examined properties of CBsc receptors in Sprague Dawley (SD) rats and two strains of wild‐type (WT) mice (C57BL/6J and CD1) used as backgrounds for two independent lines of CB1–/– mice (Ledent et al., 1999; Zimmer et al., 1999). The inhibition of synaptic glutamate release by WIN55,212‐2 was observed in hippocampal slices from WT CD1 mice and SD rats but was absent in WT C57 mice. We also found that AM251 and SR141716A antagonized the effect of WIN55,212‐2 in hippocampal slices from CD1 mice and SD rats demonstrating a lack of selectivity of these ligands for CB1 and CBsc receptors in these animals. The results indicate that the glutamate‐modulating CBsc cannabinoid receptor is present in the hippocampi of CD1 mice and SD rats but not in C57BL/6J mice. Thus, we have identified animal models that may permit the study of cannabinoids independently of the novel CBsc receptor (C57CB1+/+), the CBsc receptor independently of the cloned CB1 receptor (CD1CB1–/–), or in the absence of both receptors (C57CB1–/–).
Unilateral lesion of the pedunculopontine nucleus induces hyperactivity in the subthalamic nucleus and substantia nigra in the rat
Authors: Breit S. , Lessmann L. , Benazzouz A. , Schulz J. B.
Published: November 2005

Recent data suggest a role for the pedunculopontine nucleus (PPN) in the pathophysiology of Parkinson's disease. Although there is anatomical evidence that the PPN and the basal ganglia are reciprocally connected, the functional importance of these connections is poorly understood. Lesioning of the PPN was shown to induce akinesia in primates, whereas in the 6‐hydroxydopamine rat model the PPN was found to be hyperactive. As both nigrostriatal dopamine depletion and lesioning of the PPN were shown to induce akinesia and parkinsonism, the present study was performed in order to investigate the changes in neuronal activity of the subthalamic nucleus (STN) and the substantia nigra pars reticulata (SNr) after unilateral ibotenic acid lesioning of the PPN and after unilateral 6‐hydroxydopamine lesioning of the substantia nigra pars compacta (SNc). The firing rate of STN neurones significantly increased from 10.2 ± 6.2 (mean ± SD) to 14.6 ± 11.7 spikes/s after lesion of the PPN and to 18.6 ± 14.5 spikes/s after lesion of the SNc. The activity of the SNr significantly increased from 19.6 ± 10.5 to 28.7 ± 13.4 spikes/s after PPN lesioning and to 23.5 ± 10.8 spikes/s after SNc lesioning. Furthermore, PPN lesion decreased the number of spontaneously firing dopaminergic SNc cells, while having no effect on their firing rate. The results of our study show that lesion of the PPN leads to hyperactivity of the STN and SNr, similar to the changes induced by lesion of the SNc. Moreover, the decreased activity of SNc cells observed after PPN lesion might be at the origin of activity changes in the STN and SNr.
Identification of an ectodomain within the LAR protein tyrosine phosphatase receptor that binds homophilically and activates signalling pathways promoting neurite outgrowth
Authors: Yang Tao , Yin Weining , Derevyanny Vicki D. , Moore Laura A. , Longo Frank M.
Published: November 2005

Elucidation of mechanisms by which receptor protein tyrosine phosphatases (PTPs) regulate neurite outgrowth will require characterization of ligand–receptor interactions and identification of ligand‐induced signalling components mediating neurite outgrowth. The first identified ligand of the leucocyte common antigen‐related (LAR) receptor PTP consists of a 99‐residue ectodomain isoform, termed LARFN5C, which undergoes homophilic binding to LAR and promotes neurite outgrowth. We employed peptide mapping of LARFN5C to identify an active neurite‐promoting domain of LAR. A peptide mimetic consisting of 37 residues (L59) and corresponding to the fifth LAR fibronectin type III (FNIII) domain prevented LARFN5C homophilic binding, demonstrated homophilic binding to itself and promoted neurite outgrowth of mouse E16–17 hippocampal neurons and of dorsal root ganglia explants. Response to L59 was partially lost when using neurons derived from LAR‐deficient (–/–) mice or neurons treated with LAR siRNA, consistent with homophilic interaction of L59 with LAR. L59 neurite‐promoting activity was decreased in the presence of inhibitors of Src, Trk, PLCγ, PKC, PI3K and MAPK. L59 activated Src (a known substrate of LAR), FAK and TrkB and also activated downstream signalling intermediates including PKC, ERK, AKT and CREB. BDNF augmented the maximal neurite‐promoting activity of L59, a finding consistent with the presence of shared and distinct signalling pathways activated by L59 with BDNF and L59 with TrkB. These studies are the first to identify an ectodomain of LAR (located within the fifth FNIII domain) capable of promoting neurite outgrowth and point to novel approaches for promotion of neurite outgrowth.
Cell type‐specific regulation of RE‐1 silencing transcription factor (REST) target genes
Authors: Hohl Mathias , Thiel Gerald
Published: November 2005

RE‐1 silencing transcription factor (REST) is a transcriptional repressor that represses neuronal gene transcription in non‐neuronal cells. REST target genes are expressed in neurons and in neuroendocrine cells. Here, we show that treatment with the histone deacetylase inhibitor trichostatin A (TSA) or expression of a mutant of REST (DP‐REST:ER) that contains a transcriptional activation domain enhanced expression of the REST target genes encoding synaptophysin and secretogranin II in neuronal as well as in neuroendocrine cells. These data indicate that the synaptophysin and secretogranin II genes are similarly regulated in neuronal and neuroendocrine cells. In contrast, expression of the connexin36 gene was inducible by TSA or DP‐REST:ER only in pancreatic α and β cells, but not in neuronal and pituitary cells, indicating that transcriptional repression by REST functions in a cell type‐specific manner. Expression of the BDNF and GluR2 genes, both described as targets of REST, was not induced by either TSA or expression of DP‐REST:ER in neuronal or neuroendocrine cells. Chromatin immunoprecipitation experiments using antibodies directed against methylated histone H3Lys4 or H3Lys9 showed a perfect correlation between expression of REST target genes in different cell types and nucleosomal modifications that distinguish active from inactive genes. We conclude that the cell type‐specific microenvironment, in particular the cell type‐specific structure of the chromatin, is crucial for the ability of REST to control gene transcription.
Photic inhibition of TrkB/Ras activity in the pigeon's tectum during development: impact on brain asymmetry formation
Authors: Manns Martina , Güntürkün Onur , Heumann Rolf , Blöchl Andrea
Published: November 2005

Asymmetric photic stimulation during embryonic or post‐hatch development induces a functional lateralization of the pigeon's visual system, which is accompanied by left–right differences in tectal cell sizes. The intracellular membrane‐anchored GTPase Ras can be activated by a number of upstream mechanisms including binding of brain‐derived neurotrophic factor to its specific TrkB receptor. Ras activity plays an important morphogenetic role in neurons and therefore might also be involved in the asymmetric differentiation of tectal cells. To investigate the role of Ras, we determined the relative levels of activated Ras and of signalling active phospho‐TrkB in tecta of light‐ and dark‐incubated pigeons and combined this with an immunohistochemical detection of Ras‐GTP and TrkB receptors. While Ras activation levels did not differ between light‐ and dark‐incubated pigeons during embryonic development, directly after hatching Ras activity was significantly decreased in the stronger stimulated left tectum of light‐incubated animals. This was accompanied by lower levels of TrkB phosphorylation. Immunohistochemical staining revealed Ras‐GTP‐positive cell bodies within the efferent cell layer. These cells were TrkB‐positive and developed enlarged soma sizes within the right tectum during the first week after hatching. This association suggests asymmetric Ras activation to be involved in the asymmetric differentiation of the efferent cells as a result of asymmetric TrkB signalling. Because asymmetric light exposure occurs only during embryonic development, the observed transient asymmetric inhibition of TrkB/Ras activity after hatching may reflect differential embryonic maturation of tectal inhibitory circuits leading to a functional superiority of the right eye in the adult organism.
Segregation between acquisition and long‐term memory in sensorimotor learning
Authors: Zach Neta , Kanarek Naama , Inbar Dorrit , Grinvald Yael , Milestein Tomer , Vaadia Eilon
Published: November 2005

It is widely accepted that learning first involves generating new memories and then consolidating them into long‐term memory. Thus learning is generally viewed as a single continuous process with two sequential stages; acquisition and consolidation. Here, we tested an alternative hypothesis proposing that acquisition and consolidation take place, at least partly, in parallel. Human subjects learned two visuomotor tasks. One task required moving a cursor under visuomotor rotation and the other required arbitrary association of colour to direction of movement. Subjects learned the two tasks in sequence, and were tested for acquisition of the second immediately after learning the first, and for retention of the first on the following day. The results show that learning one task led to proactive interference to acquisition of the second. However, this interference was not accompanied by retroactive interference to consolidation of the first task, indicating that acquisition and consolidation can be uncoupled.
Morphine withdrawal‐induced morphological changes in the nucleus accumbens
Authors: Spiga Saturnino , Puddu Maria Cristina , Pisano Milena , Diana Marco
Published: November 2005

Morphine withdrawal produces a hypofunction of mesencephalic dopamine neurons that impinge upon medium spiny neurons (MSN) of the forebrain. After chronic treatment (from 20 to 140 mg/kg of morphine twice a day over 14 days at escalating doses) rats were withdrawn from chronic morphine spontaneously and pharmacologically. In these two distinct conditions we studied the effects of withdrawal on the morphology of MSN of the core and shell of the nucleus accumbens (Nacc). MSN were stained with the Golgi–Cox procedure and analysed by a confocal laser‐scanning microscope (CLSM). Our analysis shows that, shell and core MSN differed significantly for perikarya size and spine density, and the various morphine treatments did not affect the perikarya morphometry. Both spontaneous and naloxone‐induced withdrawal produced a similar reduction in spine density in MS shell neurons, as compared with MS core neurons. This effect is selectively localized at the level of second order dendritic trunks where afferents converge. By contrast, spine density counts of accumbens MSN from rats chronically treated with morphine, did not reveal any change. Collectively, the results of the present study are twofold: (i) spontaneous and pharmacologically precipitated withdrawal, but not chronic morphine per se, affects spine density of target structures of a reduced mesolimbic dopamine transmission, and (ii) the reduction of spine density in second order dendritic trunks is selectively segregated in the MSN of the shell of the Nacc. In conclusion, morphine withdrawal dramatically alters spine density, selectively in second order dendritic trunks of Nacc shell MSN, thereby further impoverishing the already abated dopamine (DA) transmission. This is in line with recent views suggesting the hypodopaminergic state as a cardinal feature of opioid dependence.
Vagal pulmonary afferents and central respiratory effects of 5‐HT in newborn rats
Authors: Glérant J.‐Ch. , Khater‐Boidin J. , Salzmann F. , Duron B.
Published: November 2005

In decerebrate newborn rats, serotonin (5‐HT) is a respiratory depressant via activation of 5‐HT2 receptors, whereas it evokes respiratory stimulant effects when applied to the isolated brainstem obtained from the newborn rat. This discrepancy could be due to deafferentation in the in vitro preparation. The aim of our study was to analyse the role of vagal afferents in the modulation of central respiratory effects of 5‐HT. In decerebrate cervically or abdominally bivagotomized newborn rats aged between 0 and 3 days, we recorded electrical activity from the diaphragm and from a hypoglossally innervated tongue muscle, as well as cardiac frequency (Fc), before and after application of 5‐HT to the floor of the IVth ventricle. The effects of related agents (a 5‐HT1A agonist, 8‐OH DPAT, and a 5‐HT2 agonist, DOI) were studied in cervically bivagotomized animals. For comparison, and to assess the spontaneous variability in inspiratory frequency (Fi) and Fc, sham groups were studied. Each group comprised ten newborn rats. In cervically bivagotomized newborn rats, 5‐HT induces a significant increase in Fi, which is the opposite to that observed in decerebrate newborn rats with intact vagi. This respiratory effect is mediated in particular, via activation of 5‐HT1A. By contrast, in abdominally bivagotomized newborn rats, a decrease in Fi was observed in response to 5‐HT (as previously described in decerebrate animals with intact vagi). We conclude that pulmonary vagal afferents modulate the central respiratory action of 5‐HT in decerebrate newborn rats, explaining the conflicting results between in vivo and in vitro experiments.
Expression of netrin‐1, slit‐1 and slit‐3 but not of slit‐2 after cerebellar and spinal cord lesions
Authors: Wehrle Rosine , Camand Emeline , Chedotal Alain , Sotelo Constantino , Dusart Isabelle
Published: November 2005

To determine whether members of the Netrin‐1 and Slit families and their receptors are expressed after central nervous system (CNS) injury, we performed in situ hybridization for netrin‐1, slit‐1, 2 and 3, and their receptors (dcc, unc5h‐1, 2 and 3, robo‐1, 2 and 3) 8 days, 2–3 months and 12–18 months after traumatic lesions of rat cerebellum. The expression pattern of these molecules was unchanged in axotomized Purkinje cells, whereas unc5h3 expression was upregulated in deafferented granule cells. Cells expressing slit‐2 or dcc were never detected at the lesion site. By contrast, cells expressing netrin‐1, slit‐1 and slit‐3, unc5h‐1, 2 and 3, and robo‐1, 2 and 3 (rig‐1) could be detected at the cerebellar lesion site as soon as 8 days after injury. Expression of unc5h‐2, robo‐1, robo‐2, slit‐1 and slit‐3 at the lesion site was maintained until 3 months, and up to 12–18 months for unc5h‐1 and 3 and robo‐3. Likewise, in the mouse spinal cord, netrin‐1, slit‐1 and slit‐3 were also expressed at the lesion site 8 days after injury. Most of the cells expressing these mRNAs were located at the centre of the lesions, suggesting that they are macrophages/activated microglial cells (macrophagic cells) or meningeal fibroblastic cells. The macrophagic nature of most Netrin‐1‐positive cells and the macrophagic or fibroblastic nature of Robo‐1‐positive cells were corroborated by double staining. Thus, Netrin‐1, Slits and their receptors may contribute to the regenerative failure of axons in the adult CNS by inhibiting axon outgrowth or by participating in the formation of the CNS scar.
Opposite impacts of tenascin‐C and tenascin‐R deficiency in mice on the functional outcome of facial nerve repair
Authors: Guntinas‐Lichius Orlando , Angelov Doychin N. , Morellini Fabio , Lenzen Mithra , Skouras Emmanouil , Schachner Melitta , Irintchev Andrey
Published: November 2005

The glycoproteins tenascin‐C (TNC) and tenascin‐R (TNR) are extracellular matrix proteins involved in the development, plasticity and repair of the nervous system. Altered expression patterns after nerve lesions in adult animals have suggested that these molecules influence axonal regeneration. To test this hypothesis, we investigated adult mice constitutively deficient in the expression of TNC, TNR or both, using the facial nerve injury paradigm. Quantitative analysis of vibrissal movements prior to nerve transection and repair (facial–facial anastomosis) did not reveal genotype‐specific differences, and thus impacts of the mutations on motor function in intact animals. Two months after nerve repair, recovery of vibrissal whisking was poor in wild‐type mice, a typical finding after facial–facial anastomosis in rodents. Differential effects of the mutations on whisking were found: recovery of function was worse in TNC‐deficient and better in TNR null mice compared with wild‐type littermates. In double‐knockout animals, vibrissal performance was insufficient, but to a lesser extent compared with TNC null mutant mice. Retrograde labelling of motoneurons in the same animals showed that similar numbers of motoneurons had reinnervated the whisker pads in all experimental groups precluding varying extents of motoneuron death and/or axon regeneration failures as causes for the different outcomes of nerve repair. Our results provide strong evidence that TNC promotes and TNR impedes recovery after nerve lesion. These findings are of particular interest with regard to the scanty knowledge about factors determining success of regeneration in the peripheral nervous system of mammals.
High‐frequency repetitive transcranial magnetic stimulation over the hand area of the primary motor cortex disturbs predictive grip force scaling
Authors: Nowak Dennis A. , Voss Martin , Huang Ying‐Zu , Wolpert Daniel M. , Rothwell John C.
Published: November 2005

When we repetitively lift an object, our grip force is influenced by the mechanical object properties of the preceding lift, irrespective of whether the subsequent lift is performed with the same hand or the hand opposite to the preceding lift. This study investigates if repetitive high‐frequency transcranial magnetic stimulation (rTMS) over the dominant primary motor cortex affects this relationship. After completion of 10 lifts of an object using the dominant hand, rTMS was applied over the dominant primary motor cortex for 20 s. On the first lift following rTMS, the peak grip force was significantly higher than on the lift preceding rTMS. Moreover, this measure remained elevated throughout the following set of lifts after rTMS. rTMS did not change the peak lift force generated by more proximal arm muscles. The same effect was observed when the lifts following rTMS over the dominant motor cortex were performed with the ipsilateral hand. These effects were not observed when subjects rested both hands on their lap or when a sham stimulation was applied for the same period of time. These preliminary data suggest that rTMS over the sensorimotor cortex disturbs predictive grip force planning.
Stimulation of PGE2 receptors EP2 and EP4 protects cultured neurons against oxidative stress and cell death following β‐amyloid exposure
Authors: Echeverria Valentina , Clerman Andrew , Doré Sylvain
Published: November 2005

Alzheimer's disease (AD) is associated with gliosis, neuroinflammation and higher levels of prostaglandins. Conflicting roles for cyclooxygenases and prostaglandins in the etiopathology of AD have been reported. We hypothesized that PGE2 signaling through EP2 and EP4 G‐protein‐coupled receptors could protect against amyloid β‐peptide (Aβ) neurotoxicity by increasing the cAMP signaling cascade. Using primary neuronal cultures, we investigated the presence of EP receptors (EP1–4) and the action of PGE2 and EP receptor agonists on neuronal susceptibility to Aβ1−42 toxicity. Low concentrations (1 µm) of PGE2, butaprost (EP2 agonist), and 1‐hydroxy‐PGE1 (EP4/EP3 agonist) were neuroprotective against Aβ1−42 toxicity, while sulprostone (EP3/EP1 agonist) at similar doses had no detectable effects. EP2 and EP4 receptor‐mediated neuroprotection would involve changes in cAMP levels, as both EP2 and EP4 agonists increased intracellular cAMP concentration by approximately doubling basal levels, and both exhibited neuroprotective actions against Aβ‐induced toxicity. The protein kinase A (PKA) inhibitor RpcAMPS significantly attenuated the neuroprotection by butaprost, but not that by 1‐hydroxy‐PGE1, implying differences between EP2 and EP4 receptor protective mechanisms. Additionally, the increase in reactive oxygen species generated following exposure to Aβ was reduced by stimulation of both EP2 and EP4 receptors. Together, these results indicate that PGE2 can protect neurons against Aβ toxicity by acting on given receptors and stimulating a cascade of intracellular events, including the cAMP–PKA pathway. We propose that development and testing of specific PGE2 receptor agonists downstream of cyclooxygenase could lead to therapeutic applications.
Central nervous system neurons acquire mast cell products via transgranulation
Authors: Wilhelm M. , Silver R. , Silverman A. J.
Published: November 2005

Resting and actively degranulating mast cells are found on the brain side of the blood–brain barrier. In the periphery, exocytosis of mast cell granules results in the release of soluble mediators and insoluble granule remnants. These mast cell constituents are found in a variety of nearby cell types, acquired by fusion of granule and cellular membranes or by cellular capture of mast cell granule remnants. These phenomena have not been studied in the brain. In the current work, light and electron microscopic studies of the medial habenula of the dove brain revealed that mast cell‐derived material can enter neurons in three ways: by direct fusion of the granule and plasma membranes (mast cell and neuron); by capture of insoluble granule remnants and, potentially, via receptor‐mediated endocytosis of gonadotropin‐releasing hormone, a soluble mediator derived from the mast cell. These processes result in differential subcellular localization of mast cell material in neurons, including free in the neuronal cytoplasm, membrane‐bound in granule‐like compartments or in association with small vesicles and the trans‐Golgi network. Capture of granule remnants is the most frequently observed form of neuronal acquisition of mast cell products and correlates quantitatively with mast cells undergoing piecemeal degranulation. The present study indicates that mast cell‐derived products can enter neurons, a process termed transgranulation, indicating a novel form of brain–immune system communication.
Opposing effects of amygdala and orbital prefrontal cortex lesions on the extinction of instrumental responding in macaque monkeys
Authors: Izquierdo Alicia , Murray Elisabeth A.
Published: November 2005

Extinction is a well‐known behavioural phenomenon that allows organisms to respond flexibly to a changing environment. Although recent work implicates the amygdala and orbital prefrontal cortex (PFo) in extinction of Pavlovian conditioned fear and aversion, much less is known about the neural bases of instrumental extinction. To explore the contribution of the macaque amygdala to flexible responding in the face of changing reward contingency, we tested the effects of selective, excitotoxic lesions of the amygdala on extinction of an instrumental response. For comparison, we evaluated the effects of ablation of PFo on the same task. Amygdala lesions facilitated the extinction of instrumental responses, whereas lesions of PFo had the opposite effect.
Differential involvement of the prelimbic cortex and striatum in conditioned heroin and sucrose seeking following long‐term extinction
Authors: Schmidt E. Donné , Voorn Pieter , Binnekade Rob , Schoffelmeer Anton N. M. , De Vries Taco J.
Published: November 2005

Relapse to drug taking is triggered by stimuli previously associated with consumption of drugs of misuse (cues) and involves brain systems controlling motivated behaviour towards natural reinforcers. In this study, we aimed to identify and compare neuronal pathways in corticostriatal systems that control conditioned heroin or natural reward (sucrose) seeking. To that end, rats were trained to self‐administer heroin or sucrose in association with an identical compound cue. After more than 3 weeks of abstinence during extinction training, cue exposure robustly reinstated heroin and sucrose seeking, but induced distinct and even opposing changes in the expression of the neuronal activation marker zif268 in the prelimbic cortex and striatal complex, respectively. Because in the prelimbic area zif268 expression was enhanced during cue‐induced heroin seeking but unaffected during sucrose seeking, a pharmacological intervention was aimed at this prefrontal region. Injection of a GABA agonist mixture within the prelimbic area enhanced conditioned heroin seeking, but had no effect on conditioned sucrose seeking. Our findings suggest a differential role of the prelimbic area and the striatum in the persistence of heroin vs. sucrose seeking following long‐term extinction.
Parasitism of Cameraria ohridella (Lepidoptera, Gracillariidae) in natural and artificial horse‐chestnut stands in the Balkans
Authors: Grabenweger G. , Avtzis N. , Girardoz S. , Hrasovec B. , Tomov R. , Kenis M.
Published: November 2005

1 The horse‐chestnut leafminer, Cameraria ohridella Deschka & Dimic, was discovered during a mass outbreak on planted horse‐chestnut trees, Aesculus hippocastanum, near Lake Ohrid in Macedonia. However, several peculiarities in the leafminer's biology and ecology, such as its inefficient control through natural enemies, indicate that it may be of exotic origin.

2 In this study, the parasitism of C. ohridella was examined in natural and artificial horse‐chestnut stands in South‐eastern Europe. The size and composition of the parasitoid complex of natural stands was comparable with that known from artificial stands. No specialist parasitoid species were detected in any of the samples. The only parasitoid species found exclusively in natural stands during this investigation were the braconid Colastes braconius and the eulophid Chrysocharis phryne. Both are known to be polyphagous on many leafminers in Europe and C. braconius has been often recorded from C. ohridella in artificial stands in previous studies. Parasitism levels varied within the same range (3.6–21.0%) throughout the entire region, in both types of habitats.

3 These results suggest that the parasitoid complex of C. ohridella in natural and planted horse‐chestnut stands in Europe is typically that of an exotic, recently introduced leafminer. Consequently, C. ohridella is probably not indigenous in the Balkans, but has been introduced to the area of its discovery from another continent.
Population dynamics ofOligonychus afrasiaticusin the southern Arava Valley of Israel in relation to date fruit characteristics and climatic conditions
Authors: Palevsky E. , Borochov‐Neori H. , Gerson U.
Published: November 2005

1 Oligonychus afrasiaticus, the old world date mite, is a serious pest of dates in North Africa and the Near East, including Israel. It attacks and rapidly develops when the fruit is young and green. Mite phenology is affected by date cultivar, but the relationship between fruit characteristics and mite population development is unknown.

2 We report that mite establishment on the main cultivars grown in Israel, ‘Medjool’, ‘Barhi’ and ‘Deglet Noor’, began only when the water content of the fruit increased to ≥ 84%. Fruit bunch architecture and resistance to penetration, as well as sugar composition and content, were not key factors in mite establishment.

3 Later in the season, when total sugar levels reached ≥ 150 mg/g fresh fruit weight, total soluble solids comprised 15% and water content decreased to ≤ 75%, mite populations declined.

4 Yearly climatic variations could be responsible for phenological asynchrony between the pest and fruit development.
Size and shape changes of Ips typographus L. (Coleoptera: Scolytinae) in relation to population level
Authors: Sallé Aurélien , Baylac Michel , Lieutier François
Published: November 2005

1 High intraspecific competition is known to occur during Ips typographus outbreaks, and is thought to be the main factor regulating epidemic populations by affecting beetle population productivity. However, little is known about the consequences of intraspecific competition on population quality during outbreaks, although it could have consequences on beetle population dynamics.

2 Ips typographus morphological variations among localities, years and beetle population levels were investigated in 10 Norway spruce (Picea abies) stands having various beetle damage intensities. Beetle size and shape estimators based on wing length, and using isometric size and log‐shape ratios, were employed. Field‐caught beetles were compared with beetles emerging from controlled breeding at different densities, performed in the laboratory. Beetles from this colony were also used to check the influence of breeding densities on the size estimator.

3 Size variations occurred among localities and years and were consistent with the epidemic or latent status of the beetle populations. Controlled breeding confirmed the negative effect of beetle densities encountered in the field on offspring size. Two hypotheses are formulated to explain this increase of intraspecific competition during an outbreak, but our data support the effect of host quality change between latent and epidemic populations.

4 Shape variations also occurred among localities but were unrelated to beetle population levels. No groups consistent with a geographical structure were found, suggesting low genetic variation for I. typographus populations in France.
Parasitoid assemblages reared from geometrid defoliators (lepidoptera: geometridae) of larch and fir in the alps
Authors: Kenis Marc , Herz Kathrin , West Richard J. , Shaw Mark R.
Published: November 2005

1 Geometrid larvae were collected from larch and fir in the Swiss Alps in 1991–94. Eight geometrid species were found in sufficient numbers to rear out parasitoids:Agriopis aurantiaria,Bupalus piniarius,Epirrita autumnata,Eupithecia lariciata,Odontopera bidentata,Lycia isabellaeandSemiothisa lituratawere collected from larch, andPuengeleria capreolariawas obtained from fir.

2 Parasitoid species belonging to five different guilds and four families were obtained; however, the taxonomic status of some of these is not completely resolved.

3 The parasitoid complex of the larch‐feeding species was totally different from that of Tortricidae and Tenthredinidae, which feed on the same host tree. In general, there was little overlap in the parasitoid complexes of the larch geometrids, with the most dominant parasitoid of each species reared from only one host. By contrast, many parasitoid species found during our study are also known to attack the same hosts or closely related hosts on different host tree species in different environments, suggesting that host specificity in geometrid parasitoids is more related to host taxonomy than to host plant or habitat.
The Interaction of Payoff Structure and Regulatory Focus in Classification
Authors: Markman Arthur B. , Baldwin Grant C. , Maddox W. Todd
Published: November 2005

This report brings together research on motivation and learning by exploring how fit of regulatory focus affects people's ability to acquire new categories. Perceptual categories were learned by people with a promotion focus (a situationally determined sensitivity to gains) or a prevention focus (a sensitivity to losses). Classification performance was closest to optimal (as determined by models fit to individual subjects' data) when the regulatory focus matched the structure of the payoffs for the categories. Promotion-focus subjects performed best when the payoffs consisted of all gains. Prevention-focus subjects performed best when the payoffs consisted of all losses.
“Tip of the Fingers” Experiences by Deaf Signers
Authors: Thompson Robin , Emmorey Karen , Gollan Tamar H.
Published: November 2005

The “tip of the fingers” phenomenon (TOF) for sign language parallels the “tip of the tongue” phenomenon (TOT) for spoken language. During a TOF, signers are sure they know a sign but cannot retrieve it. Although some theories collapse semantics and phonology in sign language and thus predict that TOFs should not occur, TOFs were elicited in the current study. Like TOTs, TOFs often resolve spontaneously, commonly involve targets that are proper names, and frequently include partial access to phonology. Specifically, signers were more likely to retrieve a target sign's handshape, location, and orientation than to retrieve its movement. Signers also frequently recalled the first letter of a finger-spelled word. The existence of TOFs supports two-stage retrieval and a division between semantics and phonology in American Sign Language. The partial phonological information available during TOFs suggests that phonological features are accessed more simultaneously during lexical access for signed language than during lexical access for spoken language.
Predicting Literacy at Age 7 From Preliteracy at Age 4
Authors: Oliver Bonamy R. , Dale Philip S. , Plomin Robert
Published: November 2005

Early literacy experience and preliteracy knowledge have been shown to predict later literacy outcomes. Using a representative sample of 3,052 same-sex twin pairs (6,104 children) in the United Kingdom, we explored phenotypic and etiological interrelationships among early literacy experience, preliteracy knowledge, and school-based literacy outcomes (reading and writing). Both literacy experience and preliteracy knowledge at age 4 significantly and independently predicted literacy at age 7. Both measures also showed genetic influence that significantly predicted literacy at age 7, although genetic mediation was stronger for preliteracy knowledge than for early literacy experience. However, for both measures, shared environmental factors explained most of the association with literacy at age 7.
Shadows of the Past
Authors: Schwartz Greg , Howard Marc W. , Jing Bing , Kahana Michael J.
Published: November 2005

We examine whether temporally defined associations play a role in item recognition. The role of these associations in recall tasks is well known; we demonstrate an important role in item recognition as well. In this study, subjects were significantly more likely to recognize a test item as having been previously experienced if the preceding test item was studied in a temporally proximal list position than if the preceding test item came from a more distant list position. Further analyses showed that this associative effect was almost entirely due to cases in which the preceding test item received a highest-confidence recognition judgment.
The influence of home on learning to read
Authors: Moon Cliff , Wells Gordon
Published: November 2005

Large scale investigations into home variables and educational success frequently demonstrate relationships between global factors such as socio‐economic status, education of parents, etc. and general educational achievement, of which attainment in reading is often taken as an index. This paper reports a small but detailed study of home influences on the early stages of learning to read within the context of the Bristol Longitudinal Language Development Research Programme. Data were derived from three sources: interviews with the parents when the children were aged 5 and 7 years; regular recordings of spontaneous conversation at home between 3 %and 5 years; assessments of reading at 5 and 7 years. Attainment in reading at age 7 was found to be strongly predicted by knowledge of literacy on entry to school, and this in turn to be predicted by parental interest in literacy and quality of verbal interaction with the child in the preschool years. The child's own pre‐school interest in literacy was not found to be strongly associated with later success. The significance of these findings is discussed.
The relation between linguistic factors identified by a principal components analysis of written style and reading comprehension as measured by cloze tests
Authors: Henry G.
Published: November 2005

60 passages are analysed using 25 linguistic factors as descriptors. These 25 linguistic variables are factor analysed using a principal components technique. The factor analysis suggests three important factors: content, syntax and redundancy. The reading comprehension difficulty of each of the 60 passages was assessed at three grade levels (5‐6; 8‐9; 11‐12) by using the cloze technique with about 900 subjects at each level. The differential influence of the three factors on reading comprehension as measured by cloze was established by regressing the factor scores on the cloze results. The main results are that the semantic content of a passage is the main source of difficulty for the youngest children; syntactical and redundancy factors are not relevant when the content remains too difficult, and older children are more and more able to use redundancy cues.
The influence of pictures on the derivation of meaning from children's reading materials
Authors: Coldstein Ralph , Underwood Geoffrey
Published: November 2005

This discussion is a review of experimental work designed to determine whether pictures have an effect upon the derivation of meaning from the text printed in children's reading materials. Many reading schemes emphasize the use of illustration, but for a number of different purposes ranging from the provision of a referent for a specific word, to the provision of' contextual support, and the generation of motivation for reading. Experimental studies of the interactions between pictures arid words in the cognitive system go some way to supporting three uses of illustration in (a) the provision of meanings against which the print may be compared, (b) in the development of an organized understanding of the meaning of the text, and (c) in the enhancement of subsequent recall. The danger of distraction arising from the pictures has also been investigated, and been found to lead to decoding errors in young children presented with one word at a time. An analysis of mutual interference effects between pairs of pictures and words leads to the conclusion that the cognitive representations of meanings arc organized in a semantic system common to pictures and words. Thus, any decoding errors due to interference effects are of more than local importance—they can affect comprehension and influence the stored representation.
A study of the relationship between the Stroop effect and reading age in dyslexic subjects
Authors: Hicks Carolyn , Jackson Peter
Published: November 2005

40 dyslexic subjects were given a version of the Stroop test and the magnitude of interference was plotted as a function of reading age as measured by the British Ability Scale. A negative linear relationship emerged, such that greater reading proficiency was associated with less interference. This result is discussed in the context of LaBerge and Samuel's theory of automatic information processing in reading.
Behaviour problems and their relationship to reading difficulty
Authors: Bale Peter
Published: November 2005

An investigation into the relationship between reading difficulty and maladjustment indicated that a significantly greater number of backward readers than normal readers were antisocial. The higher incidence of maladjustment was found in those backward readers with perceptual motor problems. The backward readers were also significantly more restless and uncontrolled in their behaviour. The relationship of restless hyperactive behaviour with perceptual motor difficulties is associated with an inability by the backward reader to ignore distracting stimuli and focus upon relevant perceptual information. As the restless hyperactive behaviour was present from an early age but the antisocial behaviour did not develop until he or she was experiencing difficulty with reading, it is probable that the backward reader's poor concentration and impulsive behaviour contribute both to the reading difficulty and to the development of antisocial tendencies.
Text Display Effects on the Fluency of Young Readers
Authors: Raban Bridie
Published: November 2005

The aim of this research was to investigate one of the features of text display in books printed for young readers. The feature chosen as the focus for this study was the position of the line‐break with respect to the phrase structure of the sentence. When reading aloud, children tend to equate line length with a complete sentence, thus disrupting their fluency and, possibly, comprehension. This research was specifically designed to investigate the effect of a line‐break after each word in the sentence pattern: subject‐verb‐object‐adverbial. In an associated experiment, positioning effects of the word were investigated in coordinating positions between clauses, phrases and words occurring at the end of one line or at the beginning of the next. These experimental line‐breaks were embedded in a story which had an identical parallel form in which none of the sentences was violated by line‐breaks. In total, 254 five‐ to eight‐year‐old children were tape‐recorded reading pairs of texts aloud, with a three‐week break between recordings. These tapes were analysed for disruptions of fluency and comprehension. A hierarchy of difficulty in relation to the occurrence of the line‐breaks for these sentence patterns has been identified.
Predicting Future Reading Attainment from the WPPSI
Authors: Yule William , Rigley Leslie V.
Published: November 2005

A sample of 150 children who had been tested on the WPPSI at five and a half years of age were subsequently tested on group and individual tests of reading at ages seven and eight years. Correlations of approximately ' 0.6 are reported with group tests of reading, but only low correlations were found in the sub‐sample tested individually on the Neale test.
Levels of Language Competence and Reading Ability: an Exploratory Investigation
Authors: Whyte Jean
Published: November 2005

Associations have been found between reading ability around the age of seven to eight years and communicative competence, indicating a stage corresponding to the Piagetian concrete operations stage. It was not known, however, whether children who lagged at that stage in learning to read and in acquiring communicative competence would eventually‘catch up’with their peers in both these areas. This paper reports an exploratory study of this issue with adults who had not learnt to read as children although they were of average intelligence, and had no obvious physical defect. The objectives were:

(a) to investigate whether these adults would perform on the same level as normal reading peers on language tasks requiring communicative and analytic competence;

(b) to investigate whether performance on these tasks would be related to level of vocabulary comprehension and intelligence.

No significant differences were found between the groups in their performance on the tasks involving communicative competence. However, normal readers scored significantly higher in tasks requiring analytic competence or the ability to retrieve and transform verbal material. In addition, the pattern of correlations was different for the two groups, suggesting that they had undergone different courses of cognitive development. The results cannot tell us whether the ability to read, or lack of it, influenced the development of these functions or vice versa. It seems from this investigation, however, that not all functions of oral language develop to the same extent in readers and in non‐readers, and that this is not related solely to IQ.
Cultural Group, Reading Attainments and Dialect Interference
Authors: Pumfrey Peter D. , Lee Joyce
Published: November 2005

(NB. In the interests of brevity, the British‐born children of parents of West Indian origin are referred to as the WI group and the children of parents of English origin are referred to as the E group.)

It has been suggested that, partly because of dialect interferences, WI children experience greater difficulty than E group children in various aspects of reading.

The present study compares the attainments of a sample of 20 WI and E boys and girls of equivalent intellectual ability attending a multi‐cultural inner‐city comprehensive school in a social priority area. Reading accuracy, reading comprehension and listening comprehension attainments of the children were tested by the individual administration of the Neale Analysis of Reading Ability, Forms A, B and C.

In terms of both reading accuracy and comprehension, although the group mean scores were all below the norms for their chronological ages, there were no significant mean differences between the WI and E pupils or between boys and girls. Silent reading led to significantly lower scores than did reading aloud.