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- Brakebusch, Cord, et al.
(författare)
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Brevican-deficient mice display impaired hippocampal CA1 long-term potentiation but show no obvious deficits in learning and memory
- 2002
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Ingår i: Molecular and Cellular Biology. - 0270-7306. ; 22:21, s. 7417-7427
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Tidskriftsartikel (refereegranskat)abstract
- Brevican is a brain-specific proteoglycan which is found in specialized extracellular matrix structures called perineuronal nets. Brevican increases the invasiveness of glioma cells in vivo and has been suggested to play a role in central nervous system fiber tract development. To study the role of brevican in the development and function of the brain, we generated mice lacking a functional brevican gene. These mice are viable and fertile and have a normal life span. Brain anatomy was normal, although alterations in the expression of neurocan were detected. Perineuronal nets formed but appeared to be less prominent in mutant than in wild-type mice. Brevican-deficient mice showed significant deficits in the maintenance of hippocampal long-term potentiation (LTP). However, no obvious impairment of excitatory and inhibitory synaptic transmission was found, suggesting a complex cause for the LTP defect. Detailed behavioral analysis revealed no statistically significant deficits in learning and memory. These data indicate that brevican is not crucial for brain development but has restricted structural and functional roles.
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- Wood, Sidney A J, et al.
(författare)
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A cinefluorographic study of uvular consonants in Swedish and West Greenlandic. Poster presented at the conference From Sound to Sense
- 2004
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Ingår i: From Sound to Sense: 50+ Years of Discoveries in Speech Communication (CD-ROM).
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Konferensbidrag (refereegranskat)abstract
- This poster concerns the articulation of uvular consonants with particular reference to quantal aspects of speech production. Data from X-ray motion films are presented. Two speakers of Southern Swedish give examples of [R], and one speaker of West Greenlandic Inuit gives examples of [R] and [q]. Traditionally, uvular consonants are said to be produced by articulating the dorsum against the uvula. Unfortunately, this ought not work, owing to the presence of air passages either side of the uvular: (1) these passages should prevent occlusion for a stop, (2) similarly they should prevent necessary conditions for a Bernoulli force for a tremulant, and (3) they should prevent a Reynolds number sufficiently small for fricatives. The formant transitions to vowels adjacent to these consonants suggest instead that the place of articulation is in the upper pharynx, at the same place as is constricted for [o]-like vowels. The X-ray films confirm that these three subjects constrict the upper pharynx for these consonants. But there was a difference of timing of the uvular consonant gesture for these two languages. The Swedish subjects completed the vowel as usual and then initiated the uvular tongue body gesture. The Inuit subject initiated both vowel and uvular consonant gestures earlier, so that the vocoid segment consisted of the transition to the uvular consonant, reflecting the regular pharyngeal assimilation of vowels preceding uvulars in West Greenlandic.
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- Zhou, Xiao-Hong, et al.
(författare)
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Neurocan is dispensable for brain development
- 2001
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Ingår i: Molecular and Cellular Biology. - 0270-7306. ; 21:17, s. 5970-5978
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Tidskriftsartikel (refereegranskat)abstract
- Neurocan is a component of the extracellular matrix in brain. Due to its inhibition of neuronal adhesion and outgrowth in vitro and its expression pattern in vivo it was suggested to play an important role in axon guidance and neurite growth. To study the role of neurocan in brain development we generated neurocan-deficient mice by targeted disruption of the neurocan gene. These mice are viable and fertile and have no obvious deficits in reproduction and general performance. Brain anatomy, morphology, and ultrastructure are similar to those of wild-type mice. Perineuronal nets surrounding neurons appear largely normal. Mild deficits in synaptic plasticity may exist, as maintenance of late-phase hippocampal long-term potentiation is reduced. These data indicate that neurocan has either a redundant or a more subtle function in the development of the brain.
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