bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dark‐rearing‐induced reduction of GABA and GAD and prevention of the effect by BDNF in the mouse retina
Authors: Lee Eun‐Jin , Gibo Tricia L. , Grzywacz Norberto M. 
Published: October 2006

AbstractGamma‐aminobutyric acid (GABA) is an important retinal neurotransmitter. We studied the expression of GABA, glutamate decarboxylase 65 (GAD65) and GAD67 by immunocytochemistry and Western blot, in the retinas of control and dark‐reared C57BL/6J black mice. This study asked three questions. First, is visual input necessary for the normal expression of GABA, GAD65 and GAD67? Second, can the retina recover from the effects of dark‐rearing if returned to a normal light–dark cycle? Third, does BDNF prevent the influence of dark‐rearing on the expression of GABA and GAD? At postnatal day 10 (P10), before eye opening, GABA immunoreactivity was present in the ganglion cell layer (GCL), in the innermost rows of the inner nuclear layer (INL) and throughout the inner plexiform layer (IPL) of control and dark‐reared retinas. In P30 control retinas, GABA immunoreactivity showed similar patterns to those at P10. However, in P30 dark‐reared retinas, the density of GABA‐immunoreactive cells was lower in both the INL and GCL than in control retinas. In addition, visual deprivation retarded GABA immunoreactivity in the IPL. Western blot analysis showed corresponding differences in the levels of GAD65 but not of GAD67 expression between control and dark‐rearing conditions. In our study, dark‐rearing effects were reversed when the mice were put in normal cyclic light–dark conditions for 2 weeks. Moreover, dark‐reared retinas treated with BDNF showed normal expression of both GABA and GAD65. Our data indicate that normal expression of GABA and GAD65 is dependent on visual input. Furthermore, the data suggest that BDNF controls this dependence.
BDNF occludes GABABreceptor‐mediated inhibition of GABA release in rat hippocampal CA1 pyramidal neurons
Authors: Mizoguchi Yoshito , Kitamura Akihiko , Wake Hiroaki , Ishibashi Hitoshi , Watanabe Miho , Nishimaki Takuya , Nabekura Junichi 
Published: October 2006

AbstractDuring the development of the rat hippocampus, both γ‐aminobutyric acid (GABA)Bautoreceptors and brain‐derived neurotrophic factor (BDNF) play important roles in the formation of GABAergic synapses as well as in the GABAAreceptor‐mediated transmissions. While a number of studies have reported rapid effects of BDNF on GABAAreceptor‐mediated responses, the interactions between GABABautoreceptors and BDNF are less clear. Using conventional whole‐cell patch‐clamp recordings, we demonstrated here that BDNF significantly occludes baclofen‐induced suppression of GABAAreceptor‐mediated transmissions in each of the preparations including hippocampal slices prepared from P14 rats, hippocampal CA1 pyramidal neurons isolated from P14 and P21 rats, and cultured hippocampal pyramidal neurons. This effect of BDNF was rapid and reversible, and was mediated via the activation of presynaptic TrkB receptor tyrosine kinases, and subsequent activation of phospholipase C and protein kinase C. On the contrary, in hippocampal CA1 pyramidal neurons isolated from P7 rats, BDNF failed to occlude the GABABreceptor‐mediated inhibition of GABA release. Thus, the ability of BDNF to occlude the GABABreceptor‐mediated inhibition of GABA release develops between P7 and P14. This demonstrates a novel aspect of the effects of BDNF on inhibitory transmissions in rat hippocampus, which may have some functional roles in the induction of developmental plasticity and/or pathophysiology of epilepsy.
Speech‐ and sound‐segmentation in dyslexia: evidence for a multiple‐level cortical impairment
Authors: Kujala T. , Halmetoja J. , Näätänen R. , Alku P. , Lyytinen H. , Sussman E. 
Published: October 2006

AbstractDevelopmental dyslexia involves deficits in the visual and auditory domains, but is primarily characterized by an inability to translate the written linguistic code to the sound structure. Recent research has shown that auditory dysfunctions in dyslexia might originate from impairments in early pre‐attentive processes, which affect behavioral discrimination. Previous studies have shown that whereas dyslexic individuals are deficient in discriminating sound distinctions involving consonants or simple pitch changes, discrimination of other sound aspects, such as tone duration, is intact. We hypothesized that such contrasts that can be discriminated by dyslexic individuals when heard in isolation are difficult to identify when occurring within words or structurally similar complex sound patterns. In the current study, we addressed how segments of pseudo‐words and their non‐speech counterparts are processed in dyslexia. We assessed the detection of long‐duration differences in segments of these stimuli and identified the brain processes that could be associated with the behavioral results. Consistent with previous studies, we found no early cortical sound‐duration discrimination deficit in dyslexia. However, differences between impaired and non‐impaired readers were found in the brain processes associated with sound‐change recognition as well as in the behavioral performance. This suggests that even when the early, automatic, sound discrimination processes are intact in dyslexic individuals, deficits in the later, attention‐dependent processes may lead to impaired perception of speech and other complex sounds.
Altered neuronal responses and regulation of neurotrophic proteins in the medial septum following fimbria‐fornix transection in CNTF‐ and leukaemia inhibitory factor‐deficient mice
Authors: Naumann Thomas , Steup Andreas , Schnell Oliver , Schubert Klaus Oliver , Zhi Qixia , Guijarro Christian , Kirsch Matthias , Hofmann Hans‐Dieter 
Published: October 2006

AbstractDegeneration of axotomized GABAergic septohippocampal neurones has been shown to be enhanced in ciliary neurotrophic factor (CNTF)‐deficient mice following fimbria‐fornix transection (FFT), indicating a neuroprotective function of endogenous CNTF. Paradoxically, however, the cholinergic population of septohippocampal neurones was more resistant to axotomy in these mutants. As leukaemia inhibitory factor (LIF) has been identified as a potential neuroprotective factor for the cholinergic medial septum (MS) neurones, FFT‐induced responses were compared in CNTF–/–, LIF–/–and CNTF/LIF double knockout mice. In CNTF–/–mice, FFT‐induced cholinergic degeneration was confirmed to be attenuated as compared with wildtype mice. The expression of both LIF and LIF receptor β was increased in the MS providing a possible explanation for the enhanced neuronal resistance to FFT in these animals. However, ablation of the LIF gene also produced paradoxical effects; following FFT in LIF–/–mice no loss of GABAergic or cholinergic MS neurones was detectable during the first postlesional week, suggesting that other efficient neuroprotective mechanisms are activated in these animals. In fact, enhanced activation of astrocytes, a source of neurotrophic proteins, was indicated by increased up‐regulation of glial fibrillary acidic protein and vimentin expression. In addition, mRNA levels for neurotrophin signalling components (e.g. nerve growth factor, p75NTR) were differentially regulated. The positive effect on axotomized cholinergic neurones seen in CNTF–/–and LIF–/–mice as well as the increased up‐regulation of astrogliose markers was abolished in CNTF/LIF double knockout animals. Our results indicate that endogenous CNTF and LIF are involved in the regulation of neuronal survival following central nervous system lesion and are integrated into a network of neurotrophic signals that mutually influence their expression and function.
Posterior parahippocampal gyrus lesions in the human impair egocentric learning in a virtual environment
Authors: Weniger Godehard , Irle Eva 
Published: October 2006

AbstractFunctional imaging studies have shown that the posterior parahippocampal gyrus (PHG) is involved in allocentric (world‐centered) object and scene recognition. However, the putative role of the posterior PHG in egocentric (body‐centered) spatial memory has received only limited systematic investigation. Thirty‐one subjects with pharmacoresistant medial temporal lobe epilepsy (TLE) and temporal lobe removal were compared with 19 matched healthy control subjects on a virtual reality task affording the navigation in a virtual maze (egocentric memory). Lesions of the hippocampus and PHG of TLE subjects were determined by three‐dimensional magnetic resonance imaging volumetric assessment. The results indicate that TLE subjects with right‐sided posterior PHG lesions were impaired on virtual maze acquisition when compared with controls and TLE subjects with anterior PHG lesions. Larger posterior PHG lesions were significantly related to stronger impairments in virtual maze performance. Our results point to a role of the right‐sided posterior PHG for the representation and storage of egocentric information. Moreover, access to both allocentric and egocentric streams of spatial information may enable the posterior PHG to construct a global and comprehensive representation of spatial environments.
Cajal–Retzius cells switch from expressing γ‐less to γ‐containing GABAA receptors during corticogenesis
Authors: Cheng Qing , Yeh Pamela W. L. , Yeh Hermes H. 
Published: October 2006

AbstractCajal–Retzius cells are implicated in regulating neuronal migration and lamination during corticogenesis. In rodents, Cajal–Retzius cells are transient, being prevalent in the marginal zone of the embryonic neocortex and declining over the first two postnatal weeks. While studies have examined in postnatal neocortex the properties of GABAA receptors in Cajal–Retzius cells, less is known about their disposition at embryonic stages. Here, we combined patch‐clamp electrophysiology and single‐cell mRNA profiling to probe the expression of GABAA receptors in Cajal–Retzius cells. In embryonic neocortical slices, GABA elicited GABAA receptor‐mediated current responses that were diazepam‐insensitive and inhibited by Zn2+, a pharmacological profile consistent with expression of γ‐less GABAA receptor isoforms. Non‐Cajal–Retzius cells in the same embryonic slices, on the other hand, were robustly potentiated by diazepam and were insensitive to Zn2+, typical of γ‐containing GABAA receptor isoforms, as were Cajal–Retzius cells in the postnatal neocortex. Single‐cell mRNA profiling and immunohistochemistry confirmed expression of GABAA receptor γ subunit transcript and protein, respectively, in individual reelin‐expressing cells in the postnatal cortex but not in their embryonic counterparts. We conclude that Cajal–Retzius cells express γ‐less GABAA receptors at embryonic stages and switch to expressing γ‐containing GABAA receptor isoforms during postnatal neocortical development.
Multi‐extent analysis of the relationship between pteridophyte species richness and climate
Authors: Bickford Sophia A. , Laffan Shawn W. 
Published: October 2006

ABSTRACTAim  To determine the relationship between the distribution of climate, climatic heterogeneity and pteridophyte species richness gradients in Australia, using an approach that does not assume potential relationships are spatially invariant and allows for scale effects (extent of analysis) to be explicitly examined.Location  Australia, extending from 10° S to 43° S and 112° E to 153° E.Method  Species richness within 50 × 50 km grid cells was determined using point distribution data. Climatic surfaces representing the distribution and availability of water and energy at 1 km and 5 km cell resolutions were obtained. Climate at the 50 km resolution of analysis was represented by their mean and standard deviation in that area. Relationships were assessed using geographically weighted linear regression at a range of spatial bandwidths to investigate scale effects.Results  The parameters and the predictive strength of all models varied across space at all extents of analysis. Overall, climatic variables representing water availability were more highly correlated to pteridophyte richness gradients in Australia than those representing energy. Their variance in cells further increased the strength of the relationships in topographically heterogeneous regions. Relationships with water were strong across all extents of analysis, particularly in the tropical and subtropical parts of the continent. Water availability explained less of the variation in richness at higher latitudes.Main conclusions  This study brings into question the ability of aspatial and single‐extent models, searching for a unified explanation of macro‐scaled patterns in gradients of diversity, to adequately represent reality. It showed that, across Australia, there is a positive relationship between pteridophyte species richness and water availability but the strength and nature of the relationship varies spatially with scale in a highly complex manner. The spatial variance, or actual complexity, in these relationships could not have been demonstrated had a traditional aspatial global regression approach been used. Regional scale variation in relationships may be at least as important as more general relationships for a true understanding of the distribution of broad‐scale diversity.
People, species richness and human population growth
Authors: Evans Karl L. , Van Rensburg Berndt J. , Gaston Kevin J. , Chown Steven L. 
Published: October 2006

ABSTRACTAim To investigate how the magnitude of conservation conflicts arising from positive relationships between human population size and species richness is altered during a period of marked human population growth (2% year−1).Location South Africa.Methods Anuran and avian species richness were calculated from atlas distribution maps, and human population was measured in 1996 and 2001, all at a quarter‐degree resolution. We investigated the relationships between human population size in, and its change during, these two periods and environmental energy availability. We then investigated the nature of relationships between species richness and human population size in both time periods, and its change during them; these analyses were conducted both with and without taking environmental energy availability into account. Finally, we investigated the nature of the relationships between human population size, and its change, and the proportion of protected land. Analyses were conducted both without and with taking spatial autocorrelation into account; the latter was achieved using mixed models that fitted a spatial covariance structure to the data.Results Change in human population size between 1996 and 2001 exhibited marked spatial variation, with both large increases and decreases, but was poorly correlated with environmental energy availability. The nature of the relationship between human population size and environmental energy availability did not, however, exhibit statistically significant differences regardless of whether the former was measured in 1996 or 2001. Similarly, relationships between species richness and human population size did not exhibit significant differences between the two periods. The strengths of the species–human relationships were markedly reduced when energy availability was taken into account. Change in human population size was poorly correlated with species richness. The proportion of protected land was negatively, albeit rather weakly, correlated with human population size in 1996 and 2001, and with its change between these two periods.Main conclusions Positive species–human relationships arise largely, but not entirely, because both species richness and human population size exhibit similar responses to environmental energy availability. During a period of rapid human population growth, and marked changes in the spatial variation in human population size, positive correlations remained between human population size and both anuran and avian species richness. The slope of these correlations did not, however, alter, and the most species‐rich areas are not those with the largest increases in human population. Despite marked population growth, the magnitude of conservation conflicts arising from positive species–human relationships thus appears to have remained largely unchanged.
Infant word segmentation revisited: edge alignment facilitates target extraction
Authors: Seidl Amanda , Johnson Elizabeth K. 
Published: October 2006

Abstract In a landmark study,

Jusczyk and Aslin (1995

) demonstrated that English‐learning infants are able to segment words from continuous speech at 7.5 months of age. In the current study, we explored the possibility that infants segment words from the edges of utterances more readily than the middle of utterances. The same procedure was used as in

Jusczyk and Aslin (1995

); however, our stimuli were controlled for target word location and infants were given a shorter familiarization time to avoid ceiling effects. Infants were familiarized to one word that always occurred at the edge of an utterance (sentence‐initial position for half of the infants and sentence‐final position for the other half) and one word that always occurred in sentence‐medial position. Our results demonstrate that infants segment words from the edges of an utterance more readily than from the middle of an utterance. In addition, infants segment words from utterance‐final position just as readily as they segment words from utterance‐initial position. Possible explanations for these results, as well as their implications for current models of the development of word segmentation, are discussed.
Young children's understanding of multiple object identity: appearance, pretense and function
Authors: Abelev Maxim , Markman Ellen 
Published: October 2006

AbstractEvidence from theory‐of‐mind tasks suggests that young children have substantial difficulty thinking about multiple object identity and multiple versions of reality. On the other hand, evidence from children's understanding of pretense indicates that children have little trouble understanding dual object identity and counterfactual scenarios that are involved in pretend play. Two studies reported here show that this competence is not limited to pretend play. Three‐year‐olds also understand the dual identity involved in unusual functional use (X is being used as Y), even though they have difficulty understanding deceptive appearance (X looks like Y). We suggest that children are able to distinguish extrinsic object properties from intrinsic ones (function vs. category‐membership) better than they can distinguish superficial object properties from deep ones (appearance vs. category‐membership).
Children use categories to maximize accuracy in estimation
Authors: Duffy Sean , Huttenlocher Janellen , Crawford L. Elizabeth 
Published: October 2006

Abstract The present study tests a model of category effects upon stimulus estimation in children. Prior work with adults suggests that people inductively generalize distributional information about a category of stimuli and use this information to adjust their estimates of individual stimuli in a way that maximizes average accuracy in estimation (see Huttenlocher, Hedges & Vevea, 2000). However, little is known about the developmental origin of this cognitive process. In the present study, 5‐ and 7‐year‐old children viewed stimuli that varied in size and reproduced each from memory. Consistent with the predictions of a Bayesian model of category effects on estimation, responses were adjusted toward the central value of the stimulus distribution. Additionally, the dispersion of the stimulus distribution affected the pattern of bias and variability of responses in a way that is predicted by the model. The results suggest that, like adults, children use categories for increasing average accuracy in estimating inexact stimuli.
Dissonance between the digitally created words of school and home
Authors: Dowdall Clare 
Published: October 2006

AbstractThis article considers the potential for dissonance that one 12‐year‐old child (Clare) may experience as a text producer using new technologies, when working across a range of contexts. In this ongoing case study, two types of text are explored: a computer‐generated text produced as a homework task for school, and texts produced using an Internet‐based social network site called ‘Bebo’. Key features of Clare's text production in both contexts are identified and compared in an attempt to establish the dissonance that may be experienced as she switches from one context to another. However, by placing the texts alongside each other, it can be seen that although they look markedly different, the acts of composing the texts bear some significant resemblance. The article concludes by suggesting that experiences of dissonance in relation to text production may in fact be lodged more firmly with the recipient of any text, when it fails to meet their social, cultural and linguistic expectations, than with the child composer.
Golden times of writing: the creative compliance of writing journals
Authors: Lambirth Andrew , Goouch Kathy 
Published: October 2006

AbstractThis paper examines the history, rationale, uses and abuses of writing journals in primary classrooms. We argue that writing journals form part of a pedagogy derived from an understanding of how children can be motivated to express themselves, independently of teachers. Moreover, they demonstrate the power of welcoming children's home cultures into the classroom. However, we also wish to argue that the use of writing journals is part of the teaching profession's ‘creative compliance’ that can still contribute to the marginalisation of effective educational practice. We document how, in some schools in England, writing journals have been reduced to token gestures towards creativity and independence and in effect collude with and support what is increasingly becoming a pedagogical hegemony.
Differential recognition of children's cultural practices in middle primary literacy classrooms
Authors: Nixon Helen , Comber Barbara 
Published: October 2006

AbstractThis paper argues that teachers' recognition of children's cultural practices is an important positive step in helping socio‐economically disadvantaged children engage with school literacies. Based on 21 longitudinal case studies of children's literacy development over a 3‐year period, the authors demonstrate that when children's knowledges and practices assembled in home and community spheres are treated as valuable material for school learning, children are more likely to invest in the work of acquiring school literacies. However, they also show that while some children benefit greatly from being allowed to draw on their knowledge of popular culture, sports and the outdoors, other children's interests may be ignored or excluded. Some differences in teachers' valuing of home and community cultures appeared to relate to gender dimensions.
Help for a dyslexic learner from an unlikely source: the study of Ancient Greek
Authors: Chanock Kate 
Published: October 2006

AbstractThis paper recounts the process by which a severely reading‐disabled adult student taught himself to read and write Ancient Greek, and in so doing, improved his ability to read and write in English. Initially, Keith's reading and writing were slow, difficult and inaccurate, accompanied by visual disturbance. However, motivated by a strong interest in Ancient Greek literature and philosophical ideas, Keith enlisted me (his Faculty's academic skills adviser) to help him learn the language. Working on transliteration focused Keith's attention on the alphabetic principle separately from meaning, while practising translation focused on the formal markers of meaning. Relieved of the stress of performing under pressures of time and others' expectations, Keith made good progress with Greek and, after 6 months, found himself reading more fluently in English, without visual disturbance. This paper seeks to contribute to our knowledge of how adults learn to read, looking at the interplay of motivation, phonological awareness, knowledge of how form conveys meaning, and the learning environment. It both draws upon, and raises questions for, the neuroscientific study of dyslexia.