bluuebunny/crossref_metadata_2025 huggingface dataset:
Two types of social buffering differentially mitigate conditioned fear responses
Authors: Kiyokawa Yasushi , Takeuchi Yukari , Mori Yuji
Published: July 2010

In a phenomenon known as ‘social buffering’ in various species, signals from a conspecific animal can mitigate stress responses. This buffering can be achieved either by ‘pair‐housing’ after a stressful event or by ‘pair‐exposure’ to an acute stressor with a conspecific animal. In this study, we compared the impacts of these two types of social buffering on auditory conditioned fear responses in male rats. When subjects were exposed to an auditory conditioned stimulus (CS) that had been paired with foot shocks on the previous day, they clearly exhibited behavioral (freezing), autonomic (aggravated stress‐induced hyperthermia) and neural (Fos expression) responses. Pair‐housing for 24 h with an unfamiliar rat following fear conditioning resulted in a suppressed autonomic, but not behavioral, response, with Fos expression in the lateral nucleus of the amygdala and ventrolateral periaqueductal gray. On the other hand, pair‐exposure to the CS with an unfamiliar rat eliminated the behavioral, but not the autonomic, response, with Fos expression in the basal nucleus of the amygdala and infralimbic region of the prefrontal cortex. Furthermore, subjects that had been pair‐housed and then pair‐exposed showed no behavioral, autonomic or neural responses, suggesting that the combination of the two procedures can completely block the fear conditioning sequence. These results demonstrate that two types of social buffering differentially relieve conditioned fear responses, by influencing different neural pathways in the amygdala.
Training‐induced changes in the expression of GABAA‐associated genes in the amygdala after the acquisition and extinction of Pavlovian fear
Authors: Heldt Scott A. , Ressler Kerry J.
Published: July 2010

Previous work suggests the γ‐aminobutyric acid (GABA)ergic system may be dynamically regulated during emotional learning. In the current study we examined training‐induced changes in the expression of GABAA‐related genes and the binding of GABA receptor radioligands in the amygdala after the acquisition and extinction of Pavlovian fear. Usingin situhybridization, we examined the expression pattern changes of mRNAs for GABAergic markers in the lateral, basolateral and central subdivisions of the amygdala in C57Bl/6J mice. These markers included GABA‐synthesizing enzymes (GAD67 and GAD65), major GABAAreceptor subunits (α1, α2, α3, α5, β2 and γ2) and the expression of mRNAs that are involved in a variety of GABA‐related intracellular processes, including GABA transporter‐1 (GAT1), GABAAreceptor‐associated protein and the GABAAclustering protein, gephyrin. With fear conditioning, we found decreased mRNA levels of α1, α5 and GAD67, as well as deceased benzodiazepine binding in the amygdala. Fear extinction induced an increase in mRNA levels of α2, β2, GAD67 and gephyrin, as well as a decrease in GAT1. Together, these findings indicate that the acquisition of fear induced a downregulation of mRNA markers related to a decrease in amygdala GABAergic function, whereas the acquisition of fear extinction produced an upregulation of GABAergic markers related to enhanced GABAergic transmission.
Conditioning of interictal behaviours, but not ictal behaviours, seizures or afterdischarge threshold, by kindling of the amygdala in rats
Authors: Wagner Jason P. , Corcoran Michael E.
Published: July 2010

Rats received 45 pairings of kindling or sham stimulation in distinctive contexts before a conditioned place preference/aversion test, to determine whether the stimulation and seizures were rewarding or punishing. After more pairings, rats received kindling stimulation in each context (switch test). Ictal measures in this test included afterdischarge duration, clonus duration, latency to clonus, class of convulsion and falls. After more pairings, afterdischarge threshold was measured in each context. On every fourth day of pairings, the rats' behaviour in the prestimulation interval was recorded, to measure conditioned anticipatory defensive behaviour. We partially replicated the finding of Barnes et al. (2001, Behav. Neurosci., 115, 1065–1072) that conditioned anticipatory responses and conditioned place aversion are associated with the kindling environment. However, there were no conditioned effects on any ictal measures, including afterdischarge threshold. Our results fail to support the hypothesis that conditioning is a universal mechanism for kindling.
Impaired nerve regeneration in reeler mice after peripheral nerve injury
Authors: Lorenzetto Erika , Panteri Roger , Marino Ramona , Keller Flavio , Buffelli Mario
Published: July 2010

Reelin, an extracellular matrix protein, plays an important role in the regulation of neuronal migration and cortical lamination in the developing brain. Little is known, however, about the role of this protein in axonal regeneration. We have previously shown that Reelin is secreted by Schwann cells in the peripheral nerve compartment during postnatal development and that it is up‐regulated following nerve injury in adult mice. In this work, we generated mice deficient in Reelin (reeler) that express yellow fluorescent protein (YFP) in a subset of neurons and examined the axonal regeneration following nerve crush. We found that axonal regeneration was significantly altered compared with wild‐type mice. By contrast, retrograde tracing with Fluorogold dye after sciatic nerve crush was unaffected in these mutants, being comparable with normal axonal transport observed in wild‐type. These results indicate that the absence of Reelin impairs axonal regeneration following injury and support a role for this protein in the process of peripheral nerve regeneration.
Oxidative stress on EAAC1 is involved in MPTP‐induced glutathione depletion and motor dysfunction
Authors: Aoyama Koji , Matsumura Nobuko , Watabe Masahiko , Nakaki Toshio
Published: July 2010

Excitatory amino acid carrier 1 (EAAC1) is a glutamate transporter expressed on mature neurons in the CNS, and is the primary route for uptake of the neuronal cysteine needed to produce glutathione (GSH). Parkinson's disease (PD) is a neurodegenerative disorder pathogenically related to oxidative stress and shows GSH depletion in the substantia nigra (SN). Herein, we report that 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP)‐treated mice, an experimental model of PD, showed reduced motor activity, reduced GSH contents, EAAC1 translocation to the membrane and increased levels of nitrated EAAC1. These changes were reversed by pre‐administration of n‐acetylcysteine (NAC), a membrane‐permeable cysteine precursor. Pretreatment with 7‐nitroindazole, a specific neuronal nitric oxide synthase inhibitor, also prevented both GSH depletion and nitrotyrosine formation induced by MPTP. Pretreatment with hydrogen peroxide, l‐aspartic acid β‐hydroxamate or 1‐methyl‐4‐phenylpyridinium reduced the subsequent cysteine increase in midbrain slice cultures. Studies with chloromethylfluorescein diacetate, a GSH marker, demonstrated dopaminergic neurons in the SN to have increased GSH levels after NAC treatment. These findings suggest that oxidative stress induced by MPTP may reduce neuronal cysteine uptake, via EAAC1 dysfunction, leading to impaired GSH synthesis, and that NAC would exert a protective effect against MPTP neurotoxicity by maintaining GSH levels in dopaminergic neurons.
D1 dopamine receptor activation of NFAT‐mediated striatal gene expression
Authors: Groth Rachel D. , Weick Jason P. , Bradley Katherine C. , Luoma Jessie I. , Aravamudan Bharathi , Klug Jason R. , Thomas Mark J. , Mermelstein Paul G.
Published: July 2010

Exposure to drugs of abuse activates gene expression and protein synthesis that result in long‐lasting adaptations in striatal signaling. Therefore, identification of the transcription factors that couple drug exposure to gene expression is of particular importance. Members of the nuclear factor of activated T‐cells (NFATc) family of transcription factors have recently been implicated in shaping neuronal function throughout the rodent nervous system. Here we demonstrate that regulation of NFAT‐mediated gene expression may also be a factor in drug‐induced changes to striatal functioning. In cultured rat striatal neurons, stimulation of D1 dopamine receptors induces NFAT‐dependent transcription through activation of L‐type calcium channels. Additionally, the genes encoding inositol‐1,4,5‐trisphosphate receptor type 1 and glutamate receptor subunit 2 are regulated by striatal NFATc4 activity. Consistent with thesein‐vitrodata, repeated exposure to cocaine triggers striatal NFATc4 nuclear translocation and the up‐regulation of inositol‐1,4,5‐trisphosphate receptor type 1 and glutamate receptor subunit 2 gene expressionin vivo, suggesting that cocaine‐induced increases in gene expression may be partially mediated through activation of NFAT‐dependent transcription. Collectively, these findings reveal a novel molecular pathway that may contribute to the enduring modifications in striatal functioning that occur following the administration of drugs of abuse.
Dorsal cochlear nucleus responses to somatosensory stimulation are enhanced after noise‐induced hearing loss
Authors: Shore S. E. , Koehler S. , Oldakowski M. , Hughes L. F. , Syed S.
Published: July 2010

Multisensory neurons in the dorsal cochlear nucleus (DCN) achieve their bimodal response properties [Shore (2005) Eur. J. Neurosci., 21, 3334–3348] by integrating auditory input via VIIIth nerve fibers with somatosensory input via the axons of cochlear nucleus granule cells [Shore et al. (2000) J. Comp. Neurol., 419, 271–285; Zhou & Shore (2004)J. Neurosci. Res., 78, 901–907]. A unique feature of multisensory neurons is their propensity for receiving cross‐modal compensation following sensory deprivation. Thus, we investigated the possibility that reduction of VIIIth nerve input to the cochlear nucleus results in trigeminal system compensation for the loss of auditory inputs. Responses of DCN neurons to trigeminal and bimodal (trigeminal plus acoustic) stimulation were compared in normal and noise‐damaged guinea pigs. The guinea pigs with noise‐induced hearing loss had significantly lower thresholds, shorter latencies and durations, and increased amplitudes of response to trigeminal stimulation than normal animals. Noise‐damaged animals also showed a greater proportion of inhibitory and a smaller proportion of excitatory responses compared with normal. The number of cells exhibiting bimodal integration, as well as the degree of integration, was enhanced after noise damage. In accordance with the greater proportion of inhibitory responses, bimodal integration was entirely suppressive in the noise‐damaged animals with no indication of the bimodal enhancement observed in a sub‐set of normal DCN neurons. These results suggest that projections from the trigeminal system to the cochlear nucleus are increased and/or redistributed after hearing loss. Furthermore, the finding that only neurons activated by trigeminal stimulation showed increased spontaneous rates after cochlear damage suggests that somatosensory neurons may play a role in the pathogenesis of tinnitus.
Context‐specific sensitization of cocaine‐induced locomotor activity and associated neuronal ensembles in rat nucleus accumbens
Authors: Mattson Brandi J. , Koya Eisuke , Simmons Danielle E. , Mitchell Timothy B. , Berkow Alexander , Crombag Hans S. , Hope Bruce T.
Published: July 2010

Repeated cocaine administration to rats outside their home cage induces behavioral sensitization that is strongly modulated by the drug administration environment. We hypothesized that stimuli in the drug administration environment activate specific sets of striatal neurons, called neuronal ensembles, for further cocaine‐enhanced activation, and that repeated activation of these neuronal ensembles underlies context‐specific sensitization. In the present study, we repeatedly administered cocaine or saline to rats on alternate days in two distinct environments outside the home cage, one paired with cocaine and the other with saline. On test day, cocaine challenge injections in the cocaine‐paired environment produced strongly enhanced levels of locomotor activity, while cocaine challenge injections in the saline‐paired environment did not. The corresponding record of past neuronal activation in nucleus accumbens and caudate‐putamen during repeated drug administration was assessed using FosB immunohistochemistry, while acute neuronal activation on test day was assessed usingc‐fos in situhybridization. Although only 2% of striatal neurons were FosB labeled, 87% of these FosB‐labeled neurons were co‐labeled withc‐foswhen cocaine was injected in the cocaine‐paired environment. The degree of co‐labeling was significantly less following cocaine or saline challenge injections in the saline‐paired environment. Furthermore, the total number ofc‐fos‐labeled neurons was greater with either cocaine or saline challenge injections in the cocaine‐paired environment than in the saline‐paired environment. These findings demonstrate that the drug administration environment partly determines which striatal neuronal ensembles are activated, and to what extent, following context‐specific sensitization to cocaine.
Novel neurons in ventral tegmental area fire selectively during the active phase of the diurnal cycle
Authors: Luo Alice H. , Georges François E. , Aston‐Jones Gary S.
Published: July 2010

The ventral tegmental area (VTA) contains dopamine (DA) and γ‐aminobutyric acid (GABA) neurons involved in motivation and behavioral state. These phenomena are also influenced by circadian factors. The goal of our studies was to examine the impulse activity of neurochemically identified VTA neurons during dark (active) vs light (rest) phases of the circadian cycle. Using extracellular single‐unit recordings with juxtacellular labeling in anesthetized rats, we found multiple neuronal subpopulations including ‘novel neurons’ that selectively fired during the dark phase. These novel neurons were electrophysiologically categorized into two groups, ‘novel wide‐spike’ and ‘novel thin‐spike’ neurons. Characterization of novel wide‐spike neurons found they were consistently non‐dopaminergic and non‐GABAergic [tyrosine hydroxylase (TH)(–), glutamic acid decarboxylase (GAD)(–)]. However, they were inhibited by the D2 agonist quinpirole, an effect that could be reversed by the D2 antagonist eticlopride. Physiologically, they were fast firing (mean = 18.9 ± 1.2 spikes/s), low bursting neurons (median = 6.2 ± 3.0% of spikes in bursts) with spike durations ≥ 2.0 ms, but slightly shorter than TH(+) neurons. They were also consistently non‐responsive to footpad stimulation. The novel thin‐spike neurons were neurochemically heterogeneous, and were located more ventrally than thin‐spike neurons found during the light phase. These findings reveal previously unknown populations of VTA neurons whose activities are sensitive to diurnal phase, and whose functions may be in the temporal regulation of arousal and motivational processes.
Developmental exposure to polychlorinated biphenyls PCB153 or PCB126 impairs learning ability in young but not in adult rats
Authors: Piedrafita Blanca , Erceg Slaven , Cauli Omar , Monfort Pilar , Felipo Vicente
Published: July 2010

Polychlorinated biphenyls (PCBs) are persistent organic pollutants present in the food chain and in human blood and milk. Exposure to PCBs during pregnancy and lactation leads to cognitive impairment in children. The underlying mechanisms remain unclear. Some PCBs are endocrine disrupters. The aim of this work was to assess whether exposure of rats to PCB126 (dioxin‐like) or PCB153 (non‐dioxin‐like) during pregnancy and lactation affects the ability of the pups to learn a Y maze conditional discrimination task and/or the function of the glutamate–nitric oxide (NO)–cGMP pathway in brain in vivo when the rats are young (3 months) or adult (7–8 months). After finishing the learning experiments, the function of the pathway was analysed in the same rats by in vivo brain microdialysis. The results obtained show that perinatal exposure to PCB153 or PCB126: (1) impairs learning ability in young but not in adult rats, (2) impairs the glutamate–NO–cGMP pathway function in cerebellum in vivo in young but not in adult rats and (3) affect these parameters in males and females similarly. PCB126 is around 10 000‐fold more potent than PCB153. In control rats the function of the glutamate–NO–cGMP pathway and learning ability are lower in adult than in young rats. These age‐related differences are not present in rats exposed to PCBs. The impairment of the glutamate–NO–cGMP pathway function induced at young age by developmental exposure to the PCBs could be one of the mechanisms contributing to the cognitive impairment found in children whose mothers ingested PCB‐contaminated food during pregnancy and lactation.
Motor cortical control of internal pallidal activity through glutamatergic and GABAergic inputs in awake monkeys
Authors: Tachibana Yoshihisa , Kita Hitoshi , Chiken Satomi , Takada Masahiko , Nambu Atsushi
Published: July 2010

The internal segment of the globus pallidus (GPi) receives motor‐related cortical signals mainly through the striatum, the external segment of the globus pallidus (GPe) and the subthalamic nucleus (STN). The GPi sends its outputs outside the basal ganglia and plays a key role in motor control. Extracellular unit recordings were performed in awake monkeys to explore how glutamatergic STN inputs and GABAergic striatal and GPe inputs control spontaneous activity and how these inputs contribute to motor cortex stimulation‐induced responses of GPi neurons. The typical responses of GPi neurons to cortical stimulation consisted of an early excitation, an inhibition and a late excitation. Local applications of the NMDA receptor antagonist 3‐(2‐carboxypiperazin‐4‐yl)‐propyl‐1‐phosphonic acid and/or the AMPA/kainate receptor antagonist 1,2,3,4‐tetrahydro‐6‐nitro‐2,3‐dioxo‐benzo[f]quinoxaline‐7‐sulphonamide in the vicinity of recorded GPi neurons reduced the firing rate, and abolished or attenuated both early and late excitations following cortical stimulation. Local application of the GABAA receptor antagonist gabazine increased the firing rate, induced oscillatory firings and diminished the cortically induced inhibition. Muscimol or gabazine injection into the STN or GPe also altered the firing rate, and attenuated the late excitation of GPi neurons. The gabazine injection into the STN occasionally induced dyskinesia with significantly decreased GPi activity. These data suggest that the early and late excitations are glutamatergic and induced by the cortico‐STN‐GPi and cortico‐striato‐GPe‐STN‐GPi pathways, respectively. The inhibition is GABAergic and induced by the cortico‐striato‐GPi pathway. In addition, these inputs are the main factors governing the spontaneous activity of GPi neurons.
Binocular rivalry reveals a dissociation between the subjective experience and induced gamma oscillations
Authors: Fairhall Scott L. , Hamm Jeff P. , Kirk Ian J.
Published: July 2010

Binocular rivalry occurs when separate incompatible images are presented, one to each eye. The subjective experience of viewing these stimuli is not of a fused image, rather the perceiver experiences either one or the other percept alternating across time. Manipulation of rivalry transfer, through an abrupt focal contrast change, causes the emerging percept to radiate across the declining image. This spreading percept transition has been likened to a wave of neural excitation propagating across the excitable medium of the visual cortex [H.R. Wilson et al. (2001) Nature, 412, 907–910; S.H. Lee et al. (2005) Nat. Neurosci., 8, 22–23]. Electrophysiologically, scalp‐recorded gamma oscillations (30–70 Hz) have been reported to persist for several hundred milliseconds in response to changes in the subjective experience induced by alterations in incoming sensory information (moving‐bar stimuli). Here, we used electroencephalographic recordings in the human and binocular rivalry transition to assess the role of scalp‐recorded gamma in purely subjective changes in the visual experience. Despite the protraction of perceptual binding over a 900 ms period, no deviation in the pattern of induced gamma was observed from that reported during the perceptual closure of static images. These results suggest that localized scalp‐recorded gamma oscillations are dissociable from the subjective visual experience.
Dendritic nicotinic receptors modulate backpropagating action potentials and long‐term plasticity of interneurons
Authors: Rózsa Balázs , Katona Gergely , Kaszás Attila , Szipöcs Róbert , Sylvester Vizi E.
Published: July 2010

Stratum radiatum interneurons, unlike pyramidal cells, are rich in nicotinic acetylcholine receptors (nAChRs); however, the role of these receptors in plasticity has remained elusive. As opposed to previous physiological studies, we found that functional α7‐subunit‐containing nAChRs (α7‐nAChRs) are abundant on interneuron dendrites of rats. Moreover, dendritic Ca2+transients induced by activation of α7‐nAChRs increase as a function of distance from soma. The activation of these extrasynaptic α7‐nAChRs by cholinergic agonists either facilitated or depressed backpropagating action potentials, depending on the timing of α7‐nAChR activation. We have previously shown that dendritic α7‐nAChRs are involved in the regulation of synaptic transmission, suggesting that α7‐nAChRs may play an important role in the regulation of the spike timing‐dependent plasticity. Here we provide evidence that long‐term potentiation is indeed boosted by stimulation of dendritic α7‐nAChRs. Our results suggest a new mechanism for a cholinergic switch in memory encoding and retrieval.
Parkin occurs in a stable, non‐covalent, ∼110‐kDa complex in brain
Authors: Van Humbeeck Cindy , Waelkens Etienne , Corti Olga , Brice Alexis , Vandenberghe Wim
Published: July 2010

Mutations in the gene for parkin, a 52‐kDa E3 ubiquitin ligase, are a major cause of hereditary Parkinson's disease (PD). In vitro studies have identified a large number of parkin‐interacting proteins. Whether parkin exists as a monomer or as part of a stable protein complex in vivo is uncertain. Here we demonstrate that endogenous parkin occurs in a stable, non‐covalent, ∼110‐kDa complex in native extracts from mouse brain, heart and skeletal muscle, while monomeric parkin is undetectable. Partial denaturation experiments indicate that this complex is at least a tetramer. Reported parkin‐binding partners do not show detectable association with the parkin complex on native gels. Upon overexpression in COS1, SH‐SY5Y or CHO cells, parkin accumulates predominantly as a monomer, suggesting that the interactors required for complex formation are available in limiting amounts in these cells. Importantly, PD‐linked parkin mutations significantly impair parkin complex formation. These data demonstrate that parkin oligomerizes into a stable, non‐covalent, heteromeric complex in vivo, and suggest that parkin may have as yet unidentified stable binding partners.
5‐HT2Cantagonism blocks blood oxygen level‐dependent pharmacological‐challenge magnetic resonance imaging signal in rat brain areas related to feeding
Authors: Stark Jennifer A. , McKie Shane , Davies Karen E. , Williams Steve R. , Luckman Simon M.
Published: July 2010

In this study, pharmacological‐challenge magnetic resonance imaging was used to further characterize the central action of serotonin on feeding. In both feeding and pharmacological‐challenge magnetic resonance imaging experiments, we combined 5‐HT1B/2Cagonist m‐chlorophenylpiperazine (mCPP) challenge with pre‐treatment with the selective 5‐HT1Band 5‐HT2Creceptor antagonists, SB 224289 (2.5 mg/kg) and SB 242084 (2 mg/kg), respectively. Subcutaneous injection of mCPP (3 mg/kg) completely blocked fast‐induced refeeding in freely behaving, non‐anaesthetized male rats, an effect that was not modified by the 5‐HT1Breceptor antagonist but was partially reversed by the 5‐HT2Creceptor antagonist. mCPP alone induced both positive and negative blood oxygen level‐dependent (BOLD) responses in the brains of anaesthetized rats, including in the limbic system and basal ganglia. Overall, the 5‐HT2Cantagonist SB 242084 reversed the effects elicited by mCPP, whereas the 5‐HT1Bantagonist SB 224289 had virtually no impact. SB 242084 eliminated BOLD signal in nuclei associated with the limbic system and diminished activation in basal ganglia. In addition, BOLD signal was returned to baseline levels in the cortical regions and cerebellum. These results suggest that mCPP may reduce food intake by acting specifically on brain circuits that are modulated by 5‐HT2Creceptors in the rat.
DeltaFosB accumulation in ventro‐medial caudate underlies the induction but not the expression of behavioral sensitization by both repeated amphetamine and stress
Authors: Conversi D. , Bonito‐Oliva A. , Orsini C. , Colelli V. , Cabib S.
Published: July 2010

Both repeated psychostimulants and stress have the ability to promote behavioral sensitization, i.e. enhanced behavioral response to drug challenge. To test whether the behavioral phenotype is also accompanied by similar neuroplastic adaptations, the present study evaluated changes in Fos and FosB/DeltaFosB transcription factors induced in the brain of C57BL/6J mice behaviorally sensitized by repeated amphetamine or repeated restraint stress. Groups of mice received repeated injections ofd‐amphetamine or saline in group‐specific environments. Different groups of mice experienced 2 h of restraint daily for 10 consecutive days. Amphetamine‐ pre‐treated mice, drug‐challenged in the environment in which they received drug treatments (Paired), as well as repeatedly stressed mice expressed robust sensitization to the locomotor effects of amphetamine. Both stress‐ and amphetamine‐pre‐treated groups showed changes in amphetamine‐induced Fos expression; however, none of these changes was shared by the two sensitizing treatments. Instead, accumulation of FosB/DeltaFosB immunoreactivity in the ventro‐medial caudate was common to both pre‐treatments. These results support the hypothesis that a common neuroadaptive process involving DeltaFosB accumulation in the ventro‐medial caudate underlies the induction but not the expression of behavioral sensitization by different conditions.
Coding of images of materials by macaque inferior temporal cortical neurons
Authors: Köteles Károly , De Mazière Patrick A. , Van Hulle Marc , Orban Guy A. , Vogels Rufin
Published: July 2010

Objects vary not only in their shape but also in the material from which they are made. Knowledge of the material properties can contribute to object recognition as well as indicate properties of the object (e.g. ripeness of a fruit). We examined the coding of images of materials by single neurons of the macaque inferior temporal (IT) cortex, an area known to support object recognition and categorization. Stimuli were images of 12 real materials that were illuminated from three different directions. The material textures appeared within five different outline shapes. The majority of responsive IT neurons responded selectively to the material textures, and this selectivity was largely independent of their shape selectivity. The responses of the large majority of neurons were strongly affected by illumination direction. Despite the generally weak illumination‐direction invariance of the responses, Support Vector Machines that used the neural responses as input were able to classify the materials across illumination direction better than by chance. A comparison between the responses to the original images and those to images with a random spectral phase, but matched power spectrum, indicated that the material texture selectivity did not depend merely on differences in the power spectrum but required phase information.
Tactile responses of hindpaw, forepaw and whisker neurons in the thalamic ventrobasal complex of anesthetized rats
Authors: Aguilar J. , Morales‐Botello M. L. , Foffani G.
Published: July 2010

The majority of studies investigating responses of thalamocortical neurons to tactile stimuli have focused on the whisker representation of the rat thalamus: the ventral–posterior–medial nucleus (VPM). To test whether the basic properties of thalamocortical responses to tactile stimuli could be extended to the entire ventrobasal complex, we recorded single neurons from the whisker, forepaw and hindpaw thalamic representations. We performed a systematic analysis of responses to stereotyped tactile stimuli − 500 ms pulses (i.e. ON–OFF stimuli) or 1 ms pulses (i.e. impulsive stimuli) − under two different anesthetics (pentobarbital or urethane). We obtained the following main results: (i) the tuning of cells to ON vs. OFF stimuli displayed a gradient across neurons, so that two‐thirds of cells responded more to ON stimuli and one‐third responded more to OFF stimuli; (ii) on average, response magnitudes did not differ between ON and OFF stimuli, whereas latencies of response to OFF stimuli were a few milliseconds longer; (iii) latencies of response to ON and OFF stimuli were highly correlated; (iv) responses to impulsive stimuli and ON stimuli showed a strong correlation, whereas the relationship between the responses to impulsive stimuli and OFF stimuli was subtler; (v) unlike ON responses, OFF responses did not decrease when stimuli were moved from the receptive field center to a close location in the excitatory surround. We obtained the same results for hindpaw, forepaw and whisker neurons. Our results support the view of a neurophysiologically homogeneous ventrobasal complex, in which OFF responses participate in the structure of the spatiotemporal receptive field of thalamocortical neurons for tactile stimuli.
Alterations in serotonin signalling are involved in the hyperactivity of Pitx3‐deficient mice
Authors: Smits Simone M. , Noorlander Cornelle W. , Kas Martien J. H. , Ramakers Geert M. J. , Smidt Marten P.
Published: July 2010

Pitx3 deficiency in mice causes a dramatic loss of dopaminergic neurones located in the substantia nigra pars compacta during development. This early disruption of the nigrostriatal pathway in Pitx3‐deficient mice is characterized by increased spontaneous home‐cage activity levels during the habitual sleep phase of these animals. These findings are reminiscent of the spontaneous hyperactivity in mice neonatally lesioned with 6‐hydroxydopamine, which is caused by an extensive serotonergic hyperinnervation of the striatum. The present study investigated whether an imbalance between dopamine (DA) and serotonin (5‐HT) signalling is involved in the behavioural phenotype of Pitx3‐deficient mice. Serotonergic hyperinnervation was demonstrated by increased [3H]‐citalopram autoradiographic binding specifically in the dorsal striatum of adult Pitx3‐deficient mice, indicating alterations in 5‐HT transporter levels that correlated to DA dysfunction in Pitx3 deficiency. In addition, stimulus‐induced release of DA and 5‐HT indicated an altered balance between these neurotransmitters in the dorsal striatum of Pitx3–/– mice. To determine whether the increased 5‐HT signalling was involved in the spontaneous hyperactivity during the light phase observed in Pitx3 deficiency, we treated Pitx3‐deficient and control mice with the selective irreversible tryptophan hydroxylase inhibitorp‐chlorophenylalanine to decrease 5‐HT levels. Reduction of 5‐HT levels in Pitx3‐deficient mice decreased their locomotor activity to normal levels, whereas the same treatment increased the locomotor activity levels of control mice. Taken together, our results indicate alterations in 5‐HT signalling in Pitx3‐deficient mice that underlie their spontaneous hyperactivity.
Family Relationships, Parenting Practices, the Availability of Male Family Members, and the Behavior of Inner‐City Boys in Single‐Mother and Two‐Parent Families
Authors: Florsheitn Paul , Tolan Patrick , Gorman‐Smith Deborah
Published: July 2010

The primary goal of this study was to clarify if and how differences in the functioning of single‐mother and two‐parent families relate to the occurrence of behavioral problems among inner‐city boys (ages 10–15). Data were collected on family relationships, parenting practices, the positive influence of male family members, and the severity of externalizing behavior problems. Results indicated that (1) multiple family risk factors contribute to the occurrence of behavior problems; (2) most family risk factors were generalizable to both single‐mother and two‐parent families; (3) although boys in single‐mother families were at greater risk for developing behavior problems than boys in two‐parent families, the risks associated with single motherhood were offset by a structured family environment, an effective disciplinary strategy that allowed for some degree of adolescent autonomy, and the positive involvement of a male family member; and (4) not all differences in the functioning of single‐mother and two‐parent families were associated with problem behavior, underscoring the importance of distinguishing between adaptive and maladaptive aspects of single‐mother family functioning.
Estimators Based on Data‐Driven Generalized Weighted Cramér‐von Mises Distances under Censoring – with Applications to Mixture Models
Authors: BEUTNER ERIC , BORDES LAURENT
Published: July 2010

Abstract. Estimators based on data‐driven generalized weighted Cramér‐von Mises distances are defined for data that are subject to a possible right censorship. The function used to measure the distance between the data, summarized by the Kaplan–Meier estimator, and the target model is allowed to depend on the sample size and, for example, on the number of censored items. It is shown that the estimators are consistent and asymptotically multivariate normal for everypdimensional parametric family fulfiling some mild regularity conditions. The results are applied to finite mixtures. Simulation results for finite mixtures indicate that the estimators are useful for moderate sample sizes. Furthermore, the simulation results reveal the usefulness of sample size dependent and censoring sensitive distance functions for moderate sample sizes. Moreover, the estimators for the mixing proportion seem to be fairly robust against a ‘symmetric’ contamination model even when censoring is present.
The challenge of contributing to policy making in primary care: the gendered experiences and strategies of nurses
Authors: Hughes Alison
Published: July 2010

This paper explores nurses’ experiences as members of primary care organisations set up to develop and commission health services for local communities. Nurses, alongside GPs and other health professionals, were given a place on the governing bodies (boards) of Local Health Groups – a move widely welcomed by the nursing profession as long overdue recognition of the important contribution nurses and nursing could bring to the policy arena. Nurse board members faced a number of challenges in their attempts to contribute to and influence local health policy. This ethnographic study (which involved non‐participant observation of 33 board meetings and interviews with 29 board members including nurses) suggests that medical authority and control, and hierarchical power relations between doctors and nurses on the board, were seen by nurses as significant obstacles to their participation in this new policy arena. In response to their perceived lack of power and subordinate status, nurses employed a number of strategies to negotiate their participation as board members – these included ‘getting it right’, ‘achieving the right balance’, ‘self‐presentation’ and ‘unassertiveness’. These strategies reflected and reproduced gendered identities and relations of power and raise important questions regarding the influence of nurses and nursing within policy making.
Private Benefits, Warm Glow, and Reputation in the Free and Open Source Software Production Model
Authors: CONLEY JOHN P. , KUNG FAN‐CHIN
Published: July 2010

A great deal of production and consumption behavior takes place in the context of social organizations that seem to fall outside of the traditional paradigm of profit/utility maximization. These organizations are voluntary in nature and rely on contributions from members to achieve their objectives. Examples include the Linux operating system and other FOSS projects, political movements, churches and religious groups, Habitat for Humanity, and similar charitable organizations. In this paper, we consider a world containing agents with heterogeneous abilities who may voluntarily choose to make effort contributions to one or more different public projects. Agents are motivated by a desire to be seen as significant contributors to important and valuable projects, the warm glow from the act of contributing, and a desire to directly enjoy the benefits of projects when complete. We find that contributions from others can be either strategic complements or substitutes. We show that Nash equilibria exist and study how agents’ abilities and project quality affect the equilibrium levels of contributions.
Half a Century of Public Software Institutions: Open Source as a Solution to Hold‐Up Problem
Authors: SCHWARZ MICHAEL , TAKHTEYEV YURI
Published: July 2010

We argue that the intrinsic inefficiency of proprietary software has historically created a space for alternative institutions that provide software as a public good. We discuss several sources of such inefficiency, focusing on one that has not been described in the literature: the underinvestment due to fear of hold‐up. An inefficient hold‐up occurs when a user of software must make complementary investments, when the return on such investments depends on future cooperation of the software vendor, and when contracting about a future relationship with the software vendor is not feasible. We also consider how the nature of the production function of software makes software cheaper to develop when the code is open to the end users. Our framework explains why open source dominates certain sectors of the software industry (e.g., programming languages), while being almost non existent in some other sectors (e.g., computer games). We then use our discussion of efficiency to examine the history of institutions for provision of public software from the early collaborative projects of the 1950s to the modern “open source” software institutions. We look at how such institutions have created a sustainable coalition for provision of software as a public good by organizing diverse individual incentives, both altruistic and profit‐seeking, providing open source products of tremendous commercial importance, which have come to dominate certain segments of the software industry.
The Effect of Status on Charitable Giving
Authors: KUMRU CAGRI S. , VESTERLUND LISE
Published: July 2010

Fundraisers often start their campaigns by soliciting the wealthier, more recognized, and respected individuals in a community. We examine whether the success of this solicitation ordering in part can be attributed to the fact that it enables individuals to select organizations that have a high‐status donor base. Assuming that individuals prefer to associate with individuals of higher social ranking we use a simple linear model to show that both aggregate donations and earnings are larger when high‐status donors are solicited first. We investigate the predicted comparative statics using the experimental laboratory. Inducing a status differential we reverse the contribution ordering between participants of high and low status. Consistent with current fundraising practice, we find that low‐status followers are likely to mimic donations by high‐status leaders and this encourages high‐status leaders to give. Donations are therefore larger when individuals of high status give before rather than after those of low status.
Leadership in Public Good Provision: A Timing Game Perspective
Authors: KEMPF HUBERT , GRAZIOSI GRÉGOIRE ROTA
Published: July 2010

We address in this paper the issue of leadership when two governments provide public goods to their constituencies with cross‐border externalities as both public goods are valued by consumers in both countries. We study a timing game between two different countries: before providing public goods, the two policymakers non‐cooperatively decide their preferred sequence of moves. We establish conditions under which a first‐ or second‐mover advantage emerges for each country, highlighting the role of spillovers and the complementarity or substitutability of public goods. As a result, we are able to prove that there is no leader when, for both countries, public goods are substitutable. When public goods are complements for both countries, each of them may emerge as the leader in the game. Hence a coordination issue arises. We use the notion of risk‐dominance to select the leading government. Finally, in the mixed case, the government for whom public goods are substitutable becomes the leader.
Resource Allocation in Public Agencies: Experimental Evidence
Authors: CARDENAS JUAN CAMILO , SETHI RAJIV
Published: July 2010

Many organizations, including philanthropies and public agencies, require their employees to make resource allocation decisions that are intended to serve a broad social purpose or mission. In most cases, the criteria on the basis of which scarce funds are to be allocated are imprecisely specified, leaving agents with considerable discretionary power. This paper reports results from an experiment that explores the manner in which such power is exercised. Using a sample of public servants working in education, health, child care, and nutrition programs in Colombia, and a sample of potential and actual beneficiaries of such programs, we attempt to identify the set of recipient attributes that induce the most generous responses from officials. This is done using a design we call the “distributive dictator game,” which requires officials to rank recipients, with the understanding that a higher ranking corresponds to an increased likelihood of getting a voucher convertible into cash. We find that women (especially widows), individuals with many minor dependents, and refugees from political violence are generally favored. We also find significant interaction effects between ranker and recipient attributes, with rankings varying systematically by ranker age and gender.
A Core‐Equilibrium Convergence in a Public Goods Economy
Authors: ALLOUCH NIZAR
Published: July 2010

This paper shows a core‐equilibrium convergence in a public goods economy where consumers' preferences display warm glow effects. We demonstrate that if each consumer becomes satiated to other consumers' provision, then as the economy grows large the core shrinks to the set of Edgeworth allocations. Moreover, we show that an Edgeworth allocation can be decentralized as a warm glow equilibrium.
‘Ugly but . . . important’: the Albanian Hoard and the making of the archaeological treasure in the early twentieth century
Authors: Holcomb Melanie
Published: July 2010

This paper deploys the Metropolitan Museum's Albanian (or Avar) Treasure as a case study to explore the role and value assigned to the named treasure during the early twentieth century, a moment when Americans – most notably J.P. Morgan – were among the wealthiest and most avid collectors of Byzantine and medieval art. Outlining the market conditions for such treasures, the archaeological practices that authenticated them, and the art historical categories that gave them meaning, the paper demonstrates the extent to which the archaeological treasure was a social creation built by various players: finders, dealers, scholars, museums and collectors.
Anglo‐Saxonism and Victorian archaeology: William Wylie's Fairford Graves
Authors: Williams Howard
Published: July 2010

William Wylie's Fairford Graves is prominent among a series of publications dating from the mid‐nineteenth century reporting the discovery of early medieval cemeteries and defining their national and racial significance for English history. This paper discusses interpretative themes in Wylie's text and images. It is argued that Fairford Graves was more than a set of descriptive observations upon the excavations and finds. The paper shows how Fairford Graves was a statement about Wylie's identity as well as the imagined Teutonic origins of the English. Seen in this light, the investigation, interpretation and publication of the early medieval burials from Fairford were active resources in a burgeoning Anglo‐Saxonist discourse in early Victorian society.
Balancing efficacy and safety in the management of atopic dermatitis: the role of methylprednisolone aceponate
Authors: Luger TA
Published: July 2010

Although emollients can be sufficient to manage mild atopic dermatitis (AD), acute flares resulting in moderate‐to‐severe symptoms require treatment with anti‐inflammatory agents, such as topical corticosteroids (TCs) and topical calcineurin inhibitors (TCIs). This review examines the role of a member of the newest class of TCs, the fourth‐generation compound methylprednisolone aceponate (MPA) in AD management, with reference to the chemical structure, pharmacokinetics, efficacy in AD, safety assessed in preclinical and clinical trials and dosing considerations. MPA has an optimized efficacy/safety profile with minimal local or systemic adverse effects. In addition, it offers the opportunity for once‐daily dosing, which provides benefits in terms of patient compliance with treatment.
An exploration of the influence of food labels on South African consumers' purchasing behaviour
Authors: Kempen Elizabeth , Bosman Magdalena , Bouwer Carien , Klein Riana , van der Merwe Daleen
Published: July 2010

New labelling legislation in South Africa is expected to help consumers sustain a healthy lifestyle through the food choices they make. This study was undertaken to explore a sample of South African consumers' reasons for reading labels and the influence of food labels on their purchasing behaviour. The study was conducted using focus group discussions held with label reading consumers in Potchefstroom in the North West Province of South Africa. Findings suggested that these participants read food labels to assess the nutritional value, personal benefits, health attributes and product quality. Various purchasing influences were also identified, suggesting that consumers are in some cases motivated by food labels to purchase a product, or may be unresponsive to the label or indifferent by being aware of the information but not reluctant to buy a product that does not indicate essential information. Several indirect consideration factors such as situational factors (e.g. family), extrinsic (e.g. price) and intrinsic (e.g. taste) may contribute to the purchasing behaviour of some consumers. These findings are useful to propose a perceptual model of the way in which food labels influence purchasing behaviour of a sample of South African consumers and explain the role of food labels in the purchasing decision of label‐reading consumers. This information is especially significant for new packaging and labelling initiatives as it highlights the reasons why label‐reading South African consumers read label information.
The Effects of Family Benefits on Childbearing Decisions: A Household Optimising Approach Applied to Australia*
Authors: GUEST ROSS , PARR NICK
Published: July 2010

This article analyses the effect of family benefits on childbearing decisions using an intertemporal utility maximising framework. The childbirth decisions of households are planned jointly with decisions about lifecycle consumption. The model is calibrated using data for Australia drawn, where possible, from the Household, Income and Labour Dynamics in Australia Wave 7 survey. The simulations show that changes in family benefits are likely to have both timing and quantum effects on childbirth but of a small magnitude, which tends to support findings using alternative empirical approaches. The simulations also indicate the effects of indirect family benefits, such as paid maternity leave and policies to reduce the time that mothers spend out of the labour force following child birth.