| 1. |
- Boisvert, Isabelle, et al.
(författare)
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Long-term monaural auditory deprivation and bilateral cochlear implants
- 2012
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Ingår i: NeuroReport. - : Lippincott, Williams and Wilkins. - 0959-4965 .- 1473-558X. ; 23:3, s. 195-199
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Tidskriftsartikel (refereegranskat)abstract
- Long-term binaural auditory deprivation is associated with poorer speech recognition outcomes after cochlear implantation, even for postlingual hearing loss. It is, however, unknown to what extent the outcomes of implantation are related to the peripheral changes occurring monaurally or to changes at a higher level in the auditory system related to binaural deafness. This retrospective study aimed to unravel peripheral and central contributions to cochlear implantation outcomes by comparing outcomes obtained in individual ears for adults with long-term monaural auditory deprivation (i.e. unilateral use of hearing aid) who received bilateral cochlear implants. Results showed that similar outcomes can be obtained with the implant placed in the auditory-deprived or in the aided ear. This suggests that the peripheral changes related to monaural auditory deprivation have little effect on outcomes of cochlear implantation. NeuroReport 23: 195-199
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| 2. |
- Evstigneeva, Maria D., et al.
(författare)
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Muscle contraction force and fatigue : Effects on mismatch negativity
- 2010
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Ingår i: NeuroReport. - 0959-4965 .- 1473-558X. ; 21:18, s. 1152-1156
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Tidskriftsartikel (refereegranskat)abstract
- Muscle load can affect performance of concurrent cognitive task. This effect is often explained by limited resources in the voluntary attention system. To examine whether earlier stages of cognitive information processing might be affected, we recorded the Mismatch Negativity component (MMN) of the auditory event-related brain potential before, during and after sustained handgrip at 7% and 30% of maximal voluntary contraction. MMN is an index of automatic detection of a deviating auditory event. MMN was not affected by force level. However, its amplitude at fronto-central sites decreased during the fatiguing 30% contraction, while it tended to increase during the light 7% work. Thus, muscle fatigue may affect auditory information processing at preattentive and preconscious stages, which could modify cognitive performance
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| 3. |
- Hameed, Mustafa Q, et al.
(författare)
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A rapid lateral fluid percussion injury rodent model of traumatic brain injury and post-traumatic epilepsy
- 2014
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Ingår i: NeuroReport. - : Lippincott Williams & Wilkins. - 0959-4965 .- 1473-558X. ; 25:7, s. 532-536
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Tidskriftsartikel (refereegranskat)abstract
- Traumatic brain injury is a leading cause of acquired epilepsy. Initially described in 1989, lateral fluid percussion injury (LFPI) has since become the most extensively used and well-characterized rodent traumatic brain injury and post-traumatic epilepsy model. Universal findings, particularly seizures that reliably develop after an initial latent period, are evident across studies from multiple laboratories. However, the LFPI procedure is a two-stage process, requiring initial surgical attachment of a skull fluid cannula and then reanesthesia for delivery of the epidural fluid pressure wave. We now describe a modification of the original technique, termed 'rapid lateral fluid percussion injury' (rLFPI), which allows for a one-stage procedure and thus shorter operating time and reduced anesthesia exposure. Anesthetized male Long-Evans rats were subjected to rLFPI through a length of plastic tubing fitted with a pipette tip cannula with a 4-mm aperture. The cannula opening was positioned over a craniectomy of slightly smaller diameter and exposed dura such that the edges of the cannula fit tightly when pressed to the skull with a micromanipulator. Fluid percussion was then delivered immediately thereafter, in the same surgery session. rLFPI resulted in nonlethal focal cortical injury in all animals. We previously demonstrated that the rLFPI procedure resulted in post-traumatic seizures and regional gliosis, but had not examined other histopathologic elements. Now, we show apoptotic cell death confined to the perilesional cortex and chronic pathologic changes such as ipsilesional ventriculomegaly that are seen in the classic model. We conclude that the rLFPI method is a viable alternative to classic LFPI, and - being a one-stage procedure - has the advantage of shorter experiment turnaround and reduced exposure to anesthetics.
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| 4. |
- Jaderstad, Johan, et al.
(författare)
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Hypoxic preconditioning increases gap-junctional graft and host communication
- 2010
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Ingår i: NeuroReport. - 0959-4965 .- 1473-558X. ; 21:17, s. 1126-1132
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Tidskriftsartikel (refereegranskat)abstract
- Gap-junctional intercellular communication between grafted neural stem cells (NSCs) and host cells seems to be essential for many of the functional and beneficial interactions after NSC engraftment. Gap-junctional communication is also known to increase in the central nervous system after hypoxia and ischemia. We therefore hypothesized that controlled hypoxic preconditioning of murine NSCs (C17.2) before the engraftment is a reliable method to increase connexin 43 expression and improve subsequent graft and host communication. Data indicated that 3-h exposure to hypoxia increased the number of connexin 43 aggregates in treated NSCs by 31%. This was paralleled by enhanced hemichannel function showed by faster calcein dye efflux and an augmentation of the early functional graft and host communication.
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| 5. |
- Marklund, Ellen, et al.
(författare)
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Mismatch negativity at Fz in response to within-category changes of the vowel /i
- 2014
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Ingår i: NeuroReport. - 0959-4965 .- 1473-558X. ; 25:10, s. 756-759
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Tidskriftsartikel (refereegranskat)abstract
- The amplitude of the mismatch negativity response for acoustic within-category deviations in speech stimuli was investigated by presenting participants with different exemplars of the vowel /i/ in an odd-ball paradigm. The deviants differed from the standard either in terms of fundamental frequency, the first formant, or the second formant. Changes in fundamental frequency are generally more salient than changes in the first formant, which in turn are more salient than changes in the second formant. The mismatch negativity response was expected to reflect this with greater amplitude for more salient deviations. The fundamental frequency deviants did indeed result in greater amplitude than both first formant deviants and second formant deviants, but no difference was found between the first formant deviants and the second formant deviants. It is concluded that greater difference between standard and within-category deviants across different acoustic dimensions results in greater mismatch negativity amplitude, suggesting that the processing of linguistically irrelevant changes in speech sounds may be processed similar to nonspeech sound changes.
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| 6. |
- Sand, Anders, et al.
(författare)
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Processing of unattended, simple negative pictures resists perceptual load
- 2011
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Ingår i: NeuroReport. - 0959-4965 .- 1473-558X. ; 22:7, s. 348-352
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Tidskriftsartikel (refereegranskat)abstract
- As researchers debate whether emotional pictures can be processed irrespective of spatial attention and perceptual load, negative and neutral pictures of simple figure-ground composition were shown at fixation and were surrounded by one, two, or three letters. When participants performed a picture discrimination task, there was evidence for motivated attention; that is, an early posterior negativity (EPN) and late positive potential (LPP) to negative versus neutral pictures. When participants performed a letter discrimination task, the EPN was unaffected whereas the LPP was reduced. Although performance decreased substantially with the number of letters (one to three), the LPP did not decrease further. Therefore, attention to simple, negative pictures at fixation seems to resist manipulations of perceptual load.
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| 7. |
- Seppanen, Allan, et al.
(författare)
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Neuronal collagen XVII is localized to lipofuscin granules
- 2010
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Ingår i: NeuroReport. - 0959-4965 .- 1473-558X. ; 21:17, s. 1090-1094
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Tidskriftsartikel (refereegranskat)abstract
- We have earlier shown that collagen XVII is expressed by neurons in the human brain, although its exact intracellular location and function have remained unknown. In this study we have localized collagen XVII specifically to neuronal lipofuscin granules using electron microscopy in autopsy samples from the human brainstem. Our results show that collagen XVII expression is mainly confined to an ultrastructurally definable, specific type of lipofuscin granule. The function of neuronal collagen XVII remains unclear. However, as the functional significance of lipofuscin remains debated, the presence of collagen XVII in just some types of lipofuscin may be helpful in the process of exploring the variety of neuronal, age-related lipopigments, which are as yet defined operationally rather than functionally or structurally.
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| 8. |
- Takahashi, Kayo, et al.
(författare)
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Increase in hypothalamic aromatase in macaque monkeys treated with anabolic-androgenic steroids : PET study with [C-11]vorozole
- 2011
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Ingår i: NeuroReport. - 0959-4965 .- 1473-558X. ; 22:7, s. 326-330
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Tidskriftsartikel (refereegranskat)abstract
- In an earlier study in rodents, we showed that the aromatase that converts androgens to estrogens in the preoptic area and bed nucleus of stria terminalis was significantly increased in concentration after exposure to anabolic-androgenic steroids. To confirm whether this occurs in primates, we conducted a positron emission tomographic study using macaque monkeys. Male rhesus monkeys were treated with nandrolone decanoate for 3 weeks. To measure aromatase concentrations, we performed positron emission tomographic imaging using a C-11-labeled specific aromatase inhibitor, [C-11] vorozole. After treatment with nandrolone, significant increase in [C-11] vorozole binding was observed in the hypothalamus but not other areas including the amygdala, which is also aromatase enriched. These findings in monkeys are consistent with those we obtained earlier in rats. These findings strongly suggest that aromatase in the hypothalamus may play a crucial role in the emotional instability of anabolic-androgenic steroids abusers. NeuroReport 22:326-330 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.
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| 9. |
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| 10. |
- Björkman, Anders, et al.
(författare)
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Cortical changes in dental technicians exposed to vibrating tools.
- 2010
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Ingår i: NeuroReport. - 1473-558X. ; 21, s. 722-726
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Tidskriftsartikel (refereegranskat)abstract
- To study the cortical reorganization after long time exposure to hand-held vibrating tools, we investigated 10 dental technicians with sensory neuropathy after long time exposure to vibrating tools and 10 controls for cortical changes using functional magnetic resonance imaging at 3 T. The activated volumes corresponding to individual fingers in the hand area of S1 were significantly larger in the neuropathy group than in controls. Activation in the primary motor cortex did not differ significantly from controls. These changes are likely the result of cortical reorganization following long-term non-physiological sensory input and they can partly explain the symptoms seen in vibration-induced neuropathy.
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