| 1. |
- Benjaminsson, Simon, et al.
(author)
-
Adaptive sensor drift counteraction by a modular neural network
- 2010
-
In: Neuroscience research. - : Elsevier BV. - 0168-0102 .- 1872-8111. ; 68, s. E212-E212
-
Journal article (other academic/artistic)abstract
- The response properties of sensors such as electronic noses vary in time due to internal or environmental factors. Recalibration is often costly or technically infeasible, which is why algorithms aimed at addressing the sensor drift problem at the data processing level have been developed. These falls in two categories: The pre-processing approaches, such as component correction [1], try to extract the direction and amount of drift in the training data and remove the drift component during operation. Adaptive algorithms, such as the self-organizing map [2], try to counteract the drift during runtime by adjusting the network to the incoming data.We have previously suggested a modular neural network architecture as a model of cortical layer 4 [3]. Here we show how it quite well can handle the sensor drift problem in chemosensor data. It creates a distributed and redundant code suitable for a noisy and drifting environment. A feature extraction layer governed by competitive learning allows for network adaptation during runtime. In addition, training data can be utilized to create a prediction of the underlying drift to further improve the network performance. Hence, we attempt to combine the two aforementioned methodological categories into one network model.The capabilities of the proposed network are demonstrated on surrogate data as well as real-world data collected from an electronic nose.
|
|
| 2. |
- Björklund, Martin, et al.
(author)
-
Muscle stretch-induced modulation of noxiously activated dorsal horn neurons of feline spinal cord.
- 2004
-
In: Neuroscience research. - : Elsevier BV. - 0168-0102 .- 1872-8111. ; 48:2, s. 175-184
-
Journal article (peer-reviewed)abstract
- The present work was designed to check for the possibility of interactions between mechanical innocuous and chemically induced noxious muscle afferent inputs on discharge behavior of nociceptive superficial dorsal horn neurons (SDHNs) of the spinal cord in decerebrated cats. The innocuous and noxious stimuli were applied separately and in combination, so that the effects of the innocuous stimulus on nociceptive processing could be evaluated. The innocuous stimulus consisted of ramp-and-hold stretches of the gastrocnemius muscles, whereas the noxious stimulus consisted of i.a. injections of bradykinin (BK; 0.5-1 ml, 50 microg/ml) into the arterial circulation of same muscles. Only neurons up to approximately 1mm depth and those that responded to noxious pinch of the gastrocnemius muscles were selected for further analysis. The activity of 16 dorsal horn neurons was recorded extracellularly with high-impedance glass microelectrodes, out of which seven responded to stretch, while 12 neurons responded to bradykinin injections. The bradykinin injections induced three types of responses: excitatory, inhibitory and mixed. The majority of the neurons that showed excitatory and mixed responses to bradykinin were also influenced by stretches applied directly after the bradykinin injection. In these neurons, the stretch usually counteracted the bradykinin-induced response, i.e. shortening and reducing bradykinin-induced excitation and re-exciting the cells after bradykinin-induced inhibition. The mechanism of the stretch modulation is proposed to reside in a segmental spinal control of the nociceptive transmission.
|
|
| 3. |
- Bogatikov, Evgenii, et al.
(author)
-
miR-1933-3p is upregulated in skeletal muscles of MuSK+ EAMG mice and affects Impa1 and Mrpl27
- 2020
-
In: Neuroscience research. - : Elsevier BV. - 0168-0102 .- 1872-8111. ; 151, s. 46-52
-
Journal article (peer-reviewed)abstract
- MuSK antibody seropositive (MuSK+) Myasthenia Gravis (MG) typically affects skeletal muscles of the bulbar area, including the omohyoid muscle, causing focal fatigue, weakness and atrophy. The profile of circulating extracellular microRNA (miRNA) is changed in MuSK + MG, but the intracellular miRNA profile in skeletal muscles of MuSK + MG and MuSK + experimental autoimmune MG (EAMG) remains unknown. This study elucidated the intracellular miRNA profile in the omohyoid muscle of mice with MuSK + EAMG. The levels of eleven mouse miRNAs were elevated and two mouse miRNAs were reduced in muscles of MuSK + EAMG mice. Transient expression of miR-1933-3p and miR-1930-5p in mouse muscle (C2C12) cells revealed several downregulated genes, out of which five had predicted binding sites for miR-1933-3p. The mRNA expression of mitochondrial ribosomal protein L27 (Mrpl27) and Inositol monophosphatase I (Impa1) was reduced in miR-1933-3p transfected C2C12 cells compared to control cells (p = 0.032 versus p = 0.020). Further, transient expression of miR-1933-3p reduced Impa1 protein accumulation in C2C12 cells. These findings provide novel insights of dysregulated miRNAs and their intracellular pathways in muscle tissue afflicted with MuSK + EAMG, providing a possible link to mitochondrial dysfunction and muscle atrophy observed in MuSK + MG.
|
|
| 4. |
- Brohlin, Maria, et al.
(author)
-
Characterisation of human mesenchymal stem cells following differentiation into Schwann cell-like cells
- 2009
-
In: Neuroscience research. - : Elsevier BV. - 0168-0102 .- 1872-8111. ; 64:1, s. 41-49
-
Journal article (peer-reviewed)abstract
- Cell-based therapies provide a clinically applicable and available alternative to nerve autografts. Our previous studies have characterised rat-derived mesenchymal stem cells (MSC) and here we have investigated the phenotypic, molecular and functional characteristics of human-derived MSC (hMSC) differentiated along a Schwann cell lineage. The hMSC were isolated from healthy human donors and the identity of the undifferentiated hMSC was confirmed by the detection of MSC specific cells surface markers. The hMSC were differentiated along a glial cell lineage using an established cocktail of growth factors including glial growth factor-2. Following differentiation, the hMSC expressed the key Schwann cell (SC) markers at both the transcriptional and translational level. More importantly, we show the functional effect of hMSC on neurite outgrowth using an in vitro co-culture model system with rat-derived primary sensory neurons. The number of DRG sprouting neurites was significantly enhanced in the presence of differentiated hMSC; neurite length and density (branching) were also increased. These results provide evidence that hMSC can undergo molecular, morphological and functional changes to adopt a SC-like behaviour and, therefore, could be suitable as SC substitutes for nerve repair in clinical applications.
|
|
| 5. |
- Chauhan, Mayank, et al.
(author)
-
Muscle-specific regulation of the mTOR signaling pathway in MuSK antibody seropositive (MuSK plus ) experimental autoimmune Myasthenia gravis (EAMG)
- 2013
-
In: Neuroscience research. - : Elsevier BV. - 0168-0102 .- 1872-8111. ; 77:1-2, s. 102-109
-
Journal article (peer-reviewed)abstract
- Myasthenia gravis (MG) patients with antibodies against muscle specific tyrosine kinase (MuSK+) typically present focal fatigue and atrophy of the facial and bulbar muscles, including the masseter muscle, whereas leg muscles often are clinically spared. This study addresses the regulation of the mTOR signaling pathway in the masseter muscle versus the leg muscle tibialis anterior (TA). We analyzed muscle morphology, protein levels of mTOR components as well as atrogenes and mitochondrial markers in these muscles of healthy control mice and mice with different clinical severity grades of MuSK+ experimental autoimmune MG (EAMG). Protein levels of mTOR components were reduced in the atrophic masseter muscle of MuSK+ EAMG mice, whereas enhanced accumulation of mTOR components was observed in the TA muscles. Two other muscles: omohyoid and soleus showed intermediate spectra. In conclusion, the anabolic mTOR signaling pathway is differentially regulated even in muscles with the same activity pattern in the same neuromuscular disease. This could in part explain the clinical phenotype in MuSK+ EAMG as well as in muscular dystrophies.
|
|
| 6. |
- Eliasson, Moa, et al.
(author)
-
Spider monkeys (Ateles geoffroyi) are less sensitive to the odor of aliphatic ketones than to the odor of other classes of aliphatic compounds.
- 2015
-
In: Neuroscience research. - : Elsevier. - 0168-0102 .- 1872-8111. ; 99, s. 46-54
-
Journal article (peer-reviewed)abstract
- Aliphatic ketones are widely present in body-borne and food odors of primates. Therefore, we used an operant conditioning paradigm and determined olfactory detection thresholds in four spider monkeys for a homologous series of aliphatic 2-ketones (2-butanone to 2-nonanone) and two of their isomers (3- and 4-heptanone). We found that, with the exception of the two shortest-chained ketones, all animals detected concentrations <1ppm (parts per million), and with five odorants individual animals even reached threshold values <0.1ppm. Further, we found a significant correlation between olfactory sensitivity of the spider monkeys and carbon chain length of the 2-ketones which can best be described as a U-shaped function. In contrast, no significant correlation was found between olfactory sensitivity and position of the functional carbonyl group. Across-odorant and across-species comparisons revealed the following: spider monkeys are significantly less sensitive to the odors of aliphatic ketones than to the odor of other classes of aliphatic compounds (1-alcohols, n-aldehydes, n-acetic esters, and n-carboxylic acids) sharing the same carbon length. Spider monkeys do not differ significantly in their olfactory sensitivity for aliphatic ketones from squirrel monkeys and pigtail macaques, but are significantly less sensitive to these odorants compared to human subjects and mice. These findings support the notion that neuroanatomical and genetic properties do not allow for reliable predictions with regard to a species' olfactory sensitivity. Further, we conclude that the frequency of occurrence of a class of odorants in a species' chemical environment does not allow for reliable predictions of the species' olfactory sensitivity.
|
|
| 7. |
- Forsman, Lea J, et al.
(author)
-
Differences in regional brain volume related to the extraversion–introversion dimension : a voxel based morphometry study
- 2012
-
In: Neuroscience research. - : Elsevier. - 0168-0102 .- 1872-8111. ; 72:1, s. 59-67
-
Journal article (peer-reviewed)abstract
- Extraverted individuals are sociable, behaviorally active, and happy. We report data from a voxel based morphometry study investigating, for the first time, if regional volume in gray and white matter brain regions is related to extraversion. For both gray and white matter, all correlations between extraversion and regional brain volume were negative, i.e. the regions were larger in introverts. Gray matter correlations were found in regions that included the right prefrontal cortex and the cortex around the right temporo–parietal junction – regions that are known to be involved in behavioral inhibition, introspection, and social-emotional processing, e.g. evaluation of social stimuli and reasoning about the mental states of others. White matter correlations extended from the brainstem to widespread cortical regions, and were largely due to global effects, i.e. a larger total white matter volume in introverts. We speculate that these white matter findings may reflect differences in ascending modulatory projections affecting cortical regions involved in behavioral regulation.
|
|
| 8. |
|
|
| 9. |
- Huang, Fen-Sheng, 1961, et al.
(author)
-
Bidirectional synaptic plasticity in response to single or paired pulse activation of NMDA receptors.
- 2010
-
In: Neuroscience research. - : Elsevier BV. - 1872-8111 .- 0168-0102. ; 67:2, s. 108-116
-
Journal article (peer-reviewed)abstract
- It is still incompletely known how NMDA receptors (NMDA-R) regulate bidirectional synaptic plasticity. We examined this issue by an experimental protocol in which paired pulse stimulation (PPS) with 50ms interstimulus interval and basal frequency of 0.1Hz was applied to CA1 area of rat hippocampal slices during low Mg(2+) perfusion. Under blockade of NMDA-Rs by AP5, PPS for 12-60min led to only a minor depression. In contrast, when PPS was applied in the absence of AP5, there was a prominent short-term potentiation (STP), mainly of AMPA-R mediated responses, with peak at 1min and lasting 10-15min. The STP was followed by a slowly developing long-term depression (LTD). Applying AP5 during the STP, converted it to a stable increase relative to the control pathway. Following peak STP, plasticity was controlled in a composite manner. Whereas the initial decay was counteracted by NMDA-R activation, the following LTD was dependent on such activation. Our data suggest that synaptic changes do not only depend on the instantaneous, NMDA-dependent Ca(2+) concentration in the dendritic spine, but are also influenced by prior induction events. In addition to NMDA-R driven processes, passive relaxation contributes to the synaptic plasticity and in some cases outbalances the active control.
|
|
| 10. |
- Larsson, Linda, et al.
(author)
-
Ultra-high olfactory sensitivity for the human sperm-attractant aromaticaldehyde bourgeonal in CD-1 mice
- 2011
-
In: Neuroscience research. - : Elsevier Ireland Ltd and the Japan Neuroscience Society. - 0168-0102 .- 1872-8111. ; 71:4, s. 355-360
-
Journal article (peer-reviewed)abstract
- Recent studies have shown that certain aromatic aldehydes are ligands for olfactory receptors expressedin mammalian sperm cells and induce sperm chemotaxis. Using a conditioning paradigm, the olfactorysensitivity of five CD-1 mice for seven aromatic aldehydes was investigated. With all seven stimuli, themice discriminated concentrations as low as 0.01 ppm (parts per million) from the solvent, and withbourgeonal the animals even detected concentrations as low as 0.1 ppq (parts per quadrillion) whichconstitutes the lowest olfactory detection threshold value reported in this species so far. The presence ofa tertiary butyl group in para-position (relative to the functional aldehyde group) combined with a lack ofan additional alkyl group next to the functional aldehyde group may be responsible for the extraordinarysensitivity of the mice for bourgeonal.
|
|
