bluuebunny/crossref_metadata_2025_split huggingface dataset:
mGluR‐dependent persistent firing in entorhinal cortex layer III neurons
Authors: Yoshida Motoharu , Fransén Erik , Hasselmo Michael E. 
Published: September 2008

AbstractPersistent firing is believed to be a crucial mechanism for memory function including working memory. Recent in vivo and in vitro findings suggest an involvement of metabotropic glutamate receptors (mGluRs) in persistent firing. Using whole‐cell patch‐recording techniques in a rat entorhinal cortex (EC) slice preparation, we tested whether EC layer III neurons display persistent firing due to mGluR activation, independently of cholinergic activation. Stimulation of the angular bundle drove persistent firing in 90% of the cells in the absence of a cholinergic agonist. The persistent firing was typically stable for > 4.5 min at which point persistent firing was terminated by the experimenter. The average frequency of the persistent firing was 2.1 Hz, ranging from 0.4 to 5.5 Hz. This persistent firing was observed even in the presence of atropine (2 μm), suggesting that the persistent firing can occur independent of cholinergic activation. Furthermore, ionotropic glutamate and GABAergic synaptic blockers (2 mm kynurenic acid, 100 μm picrotoxin and 1 μm CGP55845) did not block the persistent firing. On the other hand, blockers of group I mGluRs (100 μm LY367385 and 20 μm MPEP) completely blocked or suppressed the persistent firing. An agonist of group I mGluRs (20 μm DHPG) greatly enhanced the persistent firing induced by current injection. These results indicate that persistent firing can be driven through group I mGluRs in entorhinal layer III neurons, suggesting that glutamatergic synaptic input alone could enable postsynaptic neurons to hold input signals in the form of persistent firing.
Emotional context enhances auditory novelty processing: behavioural and electrophysiological evidence
Authors: Domínguez‐Borràs Judith , Garcia‐Garcia Manuel , Escera Carles 
Published: September 2008

AbstractViewing emotionally negative pictures has been proposed to attenuate brain responses towards sudden auditory events, as more attentional resources are allocated to the affective visual stimuli. However, peripheral reflexes have been shown intensified. These observations have raised the question of whether an emotional context actually facilitates or attenuates processing in the auditory novelty system. Using scalp event‐related potentials we measured brain responses induced by novel sounds when participants responded to visual stimuli displaying either threatening or neutral sceneries. We then tested the modulatory effect of the emotional task conditions on auditory responses. Novel sounds yielded a stronger behavioural disruption on subjects’ visual task performance when responding to negative pictures compared with when responding to the neutral ones. Accordingly, very early novelty‐P3 responses to novel sounds were enhanced in negative context. These results provide strong evidence that the emotional context enhances the activation of neural networks in the auditory novelty system, gating acoustic novelty processing under potentially threatening conditions.
Acute in utero morphine exposure slows G2 / M phase transition in radial glial and basal progenitor cells in the dorsal telencephalon of the E15.5 embryonic mouse
Authors: Sargeant Tim J. , Day Darren J. , Miller John H. , Steel Ryan W. J. 
Published: September 2008

AbstractThe antiproliferative effects of opiate exposure on neurogenesis in vitro have been well documented, but the effects of opiates on brain development in vivo are less well understood. We have recently shown that mu opioid receptors are expressed on radial glia of the lateral ventricle, the neuronal and glial progenitor cells of the developing cortex. In the present study we show that in vivo morphine treatment of the E15.5 mouse increases the length of the G2/M phase of the radial glial cell cycle in the dorsal telencephalon, as well as slows interkinetic nuclear migration of radial glial nuclei from the basal ventricular zone to the apical surface. A prolonged G2/M phase was also observed in basal progenitor cells. Although morphine exposure altered the duration of the cell cycle for progenitor cells in the embryonic telencephalon, it did not affect whether the progenitors remained proliferative and re‐entered the S phase, or whether they exited the cell cycle and became quiescent. In addition, morphine treatment did not change the proportion of basal to apical mitoses. These findings indicate that opioid signalling plays a role in cell cycle progression of both radial glia and basal progenitor cells in vivo in the developing cerebral cortex.
Characterization of NO‐sensitive guanylyl cyclase: expression in an identified interneuron involved in NO–cGMP‐dependent memory formation
Authors: Ribeiro Maria , Straub Volko A. , Schofield Michael , Picot Jo , Benjamin Paul R. , O’Shea Michael , Korneev Sergei A. 
Published: September 2008

AbstractIn a number of neuronal models of learning signalling by endogenous nitric oxide (NO), produced by the enzyme NO synthase (NOS), is essential for the formation of long‐term memory (LTM). For example, in the molluscan model systemLymnaea, NO is required for LTM formation in the first few hours after one‐trial reward conditioning. Furthermore, conditioning leads to transient up‐regulation of the NOS gene in identified modulatory neurons, the cerebral giant cells (CGCs), which are known to be involved in LTM formation. InLymnaeanothing is known however about the structure and localization of the major receptor for NO, the soluble guanylyl cyclase (sGC). Here we report on the cloning and characterization of both α and β subunits of NO‐sensitive sGC and show that they are coexpressed in the CGCs. Furthermore, our electrophysiological experiments on isolated CGCs show that these neurons respond to NO by generating a prolonged depolarization of the membrane potential. Moreover, we demonstrate that this depolarization is blocked by ODQ, supporting our hypothesis that it is mediated by sGC.
Charge compensation for NADPH oxidase activity in microglia in rat brain slices does not involve a proton current
Authors: De Simoni Anna , Allen Nicola J. , Attwell David 
Published: September 2008

AbstractThe membrane properties of isolated cultured microglia have been extensively studied but it is important to understand their propertiesin situ, where they protect the brain against infection, but also contribute to neurodegenerative diseases. Microglia and macrophages attack bacteria by generating reactive oxygen species, a process which involves NADPH oxidase pumping electrons out across the cell membrane. The resulting inward current evokes a depolarization, which would inhibit the activity of the NADPH oxidase if there were no charge‐compensating current which moves positive charge out across the membrane. The mechanism of this charge compensation is controversial. In neutrophils and in cultured microglia a depolarization‐activated H+conductance has been proposed to provide charge compensation, and also to remove protons generated intracellularly by the NADPH oxidase. Alternatively, a depolarization‐activated K+conductance has been proposed to mediate charge compensation. Here we show that in microglia, either in the resting state or when activated by the bacterial coat component lipopolysaccharide, both in acute and in cultured hippocampal slices, no significant H+current is detectable. This implies that the membrane properties of microglia in their normal cellular environment differ from those of cultured microglia (similarly, microglia generated a current in response to ATP but, unlike in culture, not to glutamate or GABA). Furthermore, the K+current (Kv1.3) that is activated by lipopolysaccharide is inactivated by depolarization, making it unsuitable for mediating charge compensation on a long time scale at positive voltages. Instead, charge compensation may be mediated by a previously undescribed non‐selective cation current.
Through the looking glass: counter‐mirror activation following incompatible sensorimotor learning
Authors: Catmur Caroline , Gillmeister Helge , Bird Geoffrey , Liepelt Roman , Brass Marcel , Heyes Cecilia 
Published: September 2008

AbstractThe mirror system, comprising cortical areas that allow the actions of others to be represented in the observer’s own motor system, is thought to be crucial for the development of social cognition in humans. Despite the importance of the human mirror system, little is known about its origins. We investigated the role of sensorimotor experience in the development of the mirror system. Functional magnetic resonance imaging was used to measure neural responses to observed hand and foot actions following one of two types of training. During training, participants in the Compatible (control) group made mirror responses to observed actions (hand responses were made to hand stimuli and foot responses to foot stimuli), whereas the Incompatible group made counter‐mirror responses (hand to foot and foot to hand). Comparison of these groups revealed that, after training to respond in a counter‐mirror fashion, the relative action observation properties of the mirror system were reversed; areas that showed greater responses to observation of hand actions in the Compatible group responded more strongly to observation of foot actions in the Incompatible group. These results suggest that, rather than being innate or the product of unimodal visual or motor experience, the mirror properties of the mirror system are acquired through sensorimotor learning.
Enhanced neurogenesis from neural progenitor cells with G1/S‐phase cell cycle arrest is mediated by transforming growth factor β1
Authors: Misumi Sachiyo , Kim Tae‐Sun , Jung Cha‐Gyun , Masuda Tadashi , Urakawa Susumu , Isobe Yoshiaki , Furuyama Fujiya , Nishino Hitoo , Hida Hideki 
Published: September 2008

AbstractWe have previously demonstrated that a G1/S‐phase cell cycle blocker, deferoxamine (DFO), increased the number of new neurons from rat neurosphere cultures, which correlated with prolonged expression of cyclin‐dependent kinase (cdk) inhibitor p27kip1 [H. J. Kim et al. (2006)Brain Research, 1092, 1–15]. The present study focuses on neuronal differentiation mechanisms following treatment of neural stem/progenitor cells (NPCs) with a G1/S‐phase cell cycle blocker. The addition of DFO (0.5 mm) or aphidicolin (Aph) (1.5 μm) to neurospheres for 8 h, followed by 3 days of differentiation, resulted in an increased number of neurons and neurite outgrowth. DFO induced enhanced expression of transforming growth factor (TGF)‐β1 and cdk5 at 24 h after differentiation, whereas Aph only increased TGF‐β1 expression. DFO‐induced neurogenesis and neurite outgrowth were attenuated by administration of a cdk5 inhibitor, roscovitine, suggesting that the neurogenic mechanisms differ between DFO and Aph. TGF‐β1 (10 ng/mL) did not increase neurite outgrowth but rather the number of β‐tubulin III‐positive cells, which was accompanied by enhanced p27kip1 mRNA expression. In addition, TGF‐β receptor type II expression was observed in nestin‐positive NPCs. Results indicated that DFO‐induced TGF‐β1 signaling activated smad3 translocation from the cytoplasm to the nucleus. In contrast, TGF‐β1 signaling inhibition, via a TGF‐β receptor type I inhibitor (SB‐505124), resulted in decreased DFO‐induced neurogenesis, in conjunction with decreased p27kip1 protein expression and smad3 translocation to the nucleus. These results suggest that cell cycle arrest during G1/S‐phase induces TGF‐β1 expression. This, in turn, prompts enhanced neuronal differentiation via smad3 translocation to the nucleus and subsequent p27kip1 activation in NPCs.
Neurotoxic catecholamine metabolite in nociceptors contributes to painful peripheral neuropathy
Authors: Dina Olayinka A. , Khasar Sachia G. , Alessandri‐Haber Nicole , Bogen Oliver , Chen Xiaojie , Green Paul G. , Reichling David B. , Messing Robert O. , Levine Jon D. 
Published: September 2008

AbstractThe neurotoxic effects of catecholamine metabolites have been implicated in neurodegenerative diseases. As some sensory neurons express tyrosine hydroxylase and monoamine oxidase (MAO), we investigated the potential contribution of catecholamine metabolites to neuropathic pain in a model of alcoholic neuropathy. The presence of catecholamines in sensory neurons is supported by capsaicin‐stimulated epinephrine release, an effect enhanced in ethanol‐fed rats. mRNA for enzymes in dorsal root ganglia involved in catecholamine uptake and metabolism, dopamine β‐hydroxylase and MAO‐A, were decreased by neonatal administration of capsaicin. Ethanol‐induced hyperalgesia was attenuated by systemic and local peripheral administration of inhibitors of MAO‐A, reduction of norepinephrine transporter (NET) in sensory neurons and a NET inhibitor. Finally, intradermal injection of 3,4‐dihydroxyphenylglycolaldehyde (DOPEGAL), a neurotoxic MAO‐A catecholamine metabolite, produced robust mechanical hyperalgesia. These observations suggest that catecholamines in nociceptors are metabolized to neurotoxic products by MAO‐A, which can cause neuronal dysfunction underlying neuropathic pain.
SK channel blockade promotes burst firing in dorsal raphe serotonergic neurons
Authors: Rouchet Nathalie , Waroux Olivier , Lamy Cédric , Massotte Laurent , Scuvée‐Moreau Jacqueline , Liégeois Jean‐François , Seutin Vincent 
Published: September 2008

AbstractPreviousin vivostudies have shown that blockade of small‐conductance Ca2+‐activated potassium (SK) channels enhances burst firing in dopaminergic neurons. As bursting has been found to be physiologically relevant for the synaptic release of serotonin (5‐HT), we investigated the possible role of SK channels in the control of this firing pattern in 5‐HT neurons of the dorsal raphe nucleus. In these cells, bursts are usually composed of doublets consisting of action potentials separated by a small interval (< 20 ms). Bothin vivoandin vitroextracellular recordings were performed, using anesthetized rats and rat brain slices, respectively.In vivo, the specific SK blocker UCL 1684 (200 μm) iontophoresed onto presumed 5‐HT neurons significantly increased the production of bursts in 13 out of 25 cells. Furthermore, the effect of UCL 1684 persisted in the presence of both the GABAAantagonist SR 95531 (10 mm) and the GABABantagonist CGP 35348 (10 mm), whereas these agents by themselves did not significantly influence the neuronal firing pattern.In vitro, bath superfusion of the SK channel blocker apamin (300 nm) induced bursting in only three out of 18 neurons, although it increased the coefficient of variation of the interspike intervals in all the other cells. Our results suggest that SK channel blockade promotes bursting activity in 5‐HT neurons via a direct action. An input which is present onlyin vivoseems to be important for the induction of this firing pattern in these cells.
Nonpecuniary Benefits to Farming: Implications for Supply Response to Decoupled Payments
Authors: Key Nigel , Roberts Michael J. 
Published: September 2008

AbstractWe develop a household model wherein farmers allocate labor to maximize utility from leisure, consumption, and nonpecuniary benefits from farming. The model shows that farmers with decreasing marginal utility of income respond to higher decoupled payments by decreasing off‐farm labor and increasing farm labor, resulting in greater agricultural output. We then estimate the difference between farm and off‐farm returns to labor using data from three nationally representative farm household surveys. The finding of a large on‐farm/off‐farm wage differential provides compelling evidence of substantial nonpecuniary benefits from farming.
A Model of Spatial Arbitrage with Transport Capacity Constraints and Endogenous Transport Prices
Authors: Coleman Andrew 
Published: September 2008

AbstractThis article solves a high‐frequency model of price arbitrage incorporating storage and trade when the amount of trade is limited by transport capacity constraints. In equilibrium there is considerable variation in transport prices because transport prices rise when the demand to ship goods exceeds the capacity limit. This variation is necessary to attract shipping capacity into the industry. In turn, prices in different locations differ by a time varying amount. Thus while the law of one price holds, it holds because of endogenous variation in transport prices.
Do Alternative Marketing Arrangements Increase Pork Packers' Market Power?
Authors: Zheng Xiaoyong , Vukina Tomislav 
Published: September 2008

AbstractIn this article we use structural econometrics to formally test whether the use of the alternative marketing arrangements (AMAs) by pork packers is the source of their market power on the spot (cash) market for live hogs. We specify the pork packers' conjectures of the change in the industry total market procurement of live hogs through the spot market with respect to their AMAs stocks. The test is carried out using the mandatory price reporting data. Our results show that pork packers have statistically significant market power on the spot market for live hogs, but the source of that market power cannot be narrowed down to the existence of AMAs stocks.
Pareto‐Improving Water Management over Space and Time: The Honolulu Case
Authors: Pitafi Basharat A. , Roumasset James A. 
Published: September 2008

AbstractWe model welfare gains from efficient allocation of groundwater over space and time relative to the status quo policy of financial cost recovery. In order to promote political feasibility, an intertemporal compensation plan is devised that renders the reform Pareto‐improving. Gainers from the reform finance the compensation in proportion to their benefits through a block‐pricing scheme. For the Honolulu case, only 7% of the $441 million in gains to winners is needed to compensate losers from the reform. Future winners from the reform also repay the deficit created by the compensation package, much as state and local governments finance capital improvements.
Payment Limitations and Acreage Decisions under Risk Aversion: A Simulation Approach
Authors: Goodwin Barry K. 
Published: September 2008

AbstractPayment limits have played an important role in U.S. farm policy deliberations for the last thirty years. Current limits are largely nonbinding. Proposals to strengthen and enforce limits are currently in discussion. We evaluate the likely effects of such proposals on acreage for corn, soybeans, wheat, cotton, and rice in several important producing states. Our results generally indicate that payment limits are unlikely to significantly affect acreage in most cases; exceptions occur for cotton and rice, where the probability that limits would be binding is much greater and thus more likely to affect production.
THE EUROPEAN SOCIAL ECONOMY: CONCEPT AND DIMENSIONS OF THE THIRD SECTOR
Authors: Monzon José Luis , Chaves Rafael 
Published: September 2008

ABSTRACT**:  In recent years a new context has emerged in Europe characterized by a larger growing Europe, the creation of a new European platform for social economy named ‘Social Economy Europe’ and an improvement in research, networks and initiatives in this area from certain European Institutions such as the European Social and Economic Committee. This paper focuses on recurrent, but needing clarification, topics such as the question of definitions, the national recognition of the concept of Social Economy and the size of this European third sector. It begins with a proposition of a conceptual delimitation of the Social Economy and of the different classes of company and organization that belong to it. Second, it identifies the different agents which, irrespective of their legal form, are part of the Social Economy in each of the member states of the European Union and to compare the different national definitions that are related to the Social Economy concept. Finally, it provides quantitative data on the European Social Economy.
Fast Food and Animal Rights: An Examination and Assessment of the Industry's Response to Social Pressure
Authors: ADAMS RONALD J. 
Published: September 2008

ABSTRACTFast food chains such as McDonald's, KFC, and Burger King are major players in the production, marketing, and consumption of animal‐derived food throughout the world. Animal rights activists are quick to point out the link between the highly efficient factory farms that supply these chains and extreme animal cruelty and environmental degradation. Strategically, fast food is well positioned to leverage change in the methods by which animals are raised and processed for human consumption. Although progress has been made as the fast food industry has responded to pressure exerted by animal rights organizations, there is little indication of true collaborative efforts that would harness the power of the market to bring about substantive changes in the way the consuming public views the issue of animal welfare and food production.
Human Rights in Global Business Ethics Codes
Authors: CARASCO EMILY F. , SINGH JANG B. 
Published: September 2008

ABSTRACTThe last decade has witnessed renewed attempts to regulate the conduct of transnational corporations. One way to do this is via global ethics codes. This paper examines seven such codes (the Sullivan Principles, UN Center for Transnational Corporations’ Draft Code, OECD Guidelines, ILO's Tripartite Declaration, the Caux Round Table Principles for Business, Global Compact, and the United Nations Norms) to determine their coverage of human rights and concludes that if these initiatives succeed, particularly the more recent codes, transnational corporations may emerge as a major force in promoting human rights globally.
Local Management Response to Corporative Restructuring: A Case Study of a Company Town
Authors: SUNDSTRÖM AGNETA C. , HYDER AKMAL S. 
Published: September 2008

ABSTRACTThis is a case study of top management in a Swedish pulp industry at Skutskär. After decades of proactive response to change, starting in 1976 the pulp industry experienced a rapid and significant restructuring. In 1992, and after a prolonged hold on local investments, came a large‐scale investment with major labor reductions, which created a local crisis. The aim of this study is to analyze how top managers of a local business plant perceive and explain their citizenship relationship to the community of the company town during a transition period from 1976 to 2007. Our study shows that too much reliance on top management cost reduction requirements and not caring, or underscoring, local social concerns created gaps and local stakeholder distrust. We discuss how prolonged distrust of the company to bear social responsibility ended up in a broken relationship between the company and the local community. Our case indicates at least two problems that must be handled for successful corporate citizenship. First, the traditional control‐oriented management view is too narrow and not adjusted to today's citizenship reality, including how to handle corporate social responsibility. Second, we can see a possibility where the conceived needs on a global corporate level may lead to situations to obscure local needs and consequences.
Constitutional Philosophy, Pragmatism, and Economic Regulation*
Authors: SAGNER JAMES S. , ROSNER DAVID J. 
Published: September 2008

ABSTRACTThis article explores the various senses in which the framers of the Constitution were motivated by a pragmatist philosophical framework, and how this pragmatism influenced their vision of the best interests of the American economic system. We argue that, on various grounds, the framers would have disapproved of the excessive regulation that characterizes the current business environment.