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1

Focal stroke in the barrel cortex of rats enhances ipsilateral response to vibrissal input

100%
Jablonka J., Kossut M.
Acta Neurobiologiae Experimentalis
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2006
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tom 66
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nr 3
2

Interhemispheric activity equilibrium changes after the spreading depression waves

100%
Winiarski M., Jablonka J.
Acta Neurobiologiae Experimentalis
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2015
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tom 75
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nr Supl.
BACKGROUND AND AIMS: The study examined in a healthy rat brain the metabolic correlates of cortical activity one month after the spreading depressions (SD) episodes and its potential influence on prolonged experience dependent plasticity in the somatosensory cortex distant from the SDs focus. The SD is silenced spontaneous cortical activity propagating as a wave across one hemisphere, which follows spreading depolarisations. It is generated by disturbed ion distribution leading to increased extracellular K+ concentration. SDs are known to participate in the migraine episodes and in peri-infarct depolarisations (PiD). It was shown that after single SD episode the cortical sensory responses were altered and induced reduction of the dynamics of cortical activity rearrangement. METHODS: In our experiment six rats were subjected to unilateral SDs by administration of 3M KCl to the dura of occipital cortex. Sham and control animals underwent the same procedures, but instead of KCl received 3M NaCl or aCSF, respectively. Starting on the same day the animals had experience-dependent plasticity induced by 28 days deprivation of all but row B contralateral whiskers. After the deprivation cortical activity was mapped by 14 C-2-deoxy-Dglucose (2DG) brain mapping with bilateral rows B stimulation. RESULTS: The autoradiography revealed that the overall 2DG incorporation was higher in post-SD hemisphere than in the intact one in comparison to the control rats. The interhemispheric differences were also greater in the representations of the stimulated rows of whiskers likewise in the simultaneously stimulated auditory cortex. CONCLUSIONS: The findings suggests that SDs have no influence on experience dependent cortical map reorganisation, but may influence interhemispheric activity equilibrium increasing the excitability in the post SD hemisphere.
3

Attenuation of inflammatory response after stroke allows to retain brain plasticity

81%
Liguz-Lecznar M., Jablonka J., Kossut M.
Acta Neurobiologiae Experimentalis
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2013
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tom 73
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nr Suppl.1
Despite indications that brain plasticity may be enhanced after stroke, we have described impairment of experience-dependent plasticity in rodent cerebral cortex neighbouring the stroke-induced lesion. There is increasing evidence showing that inflammation accounts for stroke progression. Once activated, inflammatory cells can release a variety of cytotoxic agents that may induce more cell damage as well as disruption of the blood-brain barrier and extracellular matrix. We have shown that chronic treatment with anti-inflammatory drug ibuprofen restored plasticity of cortical representation of vibrissae induced by whisker deprivation. We have also the upregulation cyclooxygenase-2 (COX-2) and other proinflammatory factors, i.e. IL-1 and tumor necrosis factor TNFα shown in the acute poststroke phase. Since TNFα is one of the key players in stroke progression, we decided to reduce the TNFα signalling by introduction into the brain soluble TNFα receptors 1 that will compete for TNFα with receptors localized in the brain tissue. We have shown that such approach undertaken simultaneously with the stroke was successful in preserving the poststroke brain plasticity. Supported by Polish National Science Centre Grant: N N401 098739.
4

Restitution of sensory function of vibrissae after stroke in the barrel field coincides with activity changes in spared somatosensory cortical areas

81%
Jablonka J., Nosecka E., Kossut M.
Acta Neurobiologiae Experimentalis
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2009
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tom 69
|
nr 3
We described previously a sequence of cortical activity changes after the unilateral stroke in the whiskers somatosensory representation – the barrel fi eld (BF). We aimed to check if this activity remodeling is linked to the restitution of the whiskers sensory function. To characterize poststroke defi cits and time related recovery we performed the gap-crossing test for a group of rats 3, 28 and 56 days after the photothrombotic stroke (DPS) in the BF. Rats learned to cross the gap between elevated platforms in darkness, using only sensory information from whiskers. We examined the minimum distances at which rats failed to cross (min) and the maximal distances (max) crossed by the rats in two scenarios at each time point: (1) with all their whiskers and (2) only with unilateral whiskers corresponding to the destroyed BF (contralateral to the stroke). Before the stroke there were no signifi cant differences in min and in max distances when rats used all versus unilateral whiskers. At 3DPS the max was lower when rats used whiskers with destroyed sensory representation. The fi rst fall was made by rats at shorter distances when they used just the impaired side whiskers. At 56DPS all the differences between crossing performance disappeared. At this time point, we previously found new activity foci in the spared somatosensory cortex of the injured hemisphere, specifi c for the whiskers stimulation – probably a new functional representation of the whiskers.
5

Effect of stroke on experience dependent plasticity in the intact hemisphere

81%
Jablonka J., Kossut M., Nosecka E.
Acta Neurobiologiae Experimentalis
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2007
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tom 67
|
nr 3
6

Kernel current source density and connectivity estimation methods for the analysis of local field potentials

71%
Sredniawa W., Jablonka J., Sadowska M., Bebas P., Wojcik D. K.
Acta Neurobiologiae Experimentalis
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2017
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tom 77
|
nr Suppl.1
INTRODUCTION: Extracellular potentials, such as the Local Field Potentials (LFPs), are routinely measured in numerous electrophysiological experiments. LFP can carry valuable information about the electric properties of the tissue, however analysis of the recorded signal is usually a complex task. Apart from basic preparation, such as bandpass filtering and artifact removal, many other analytic methods have been proposed for the LFP study. Here we discuss methods for estimation of electric sources and sinks in brain tissue (Current Source Density, CSD) and methods to estimate connectivity in small networks, and their utility in analysis of cortical recordings in rats. AIM(S): Comparison of the effective connectivity and the structure of sinks and sources in cortical columns during whisker stimulations. METHOD(S): Analytic methods: kernel Current Source Density and Modular Connectivity Factorization (MCF) applied to LFP recordings and simulated data from cortical column. Experimental methods: Simultaneous multielectrode in vivo recordings from both hemispheres of the rats brain. RESULTS: Preliminary studies show different distribution of the current sources in contralateral to ipsilateral hemisphere during whisker stimulation in rats. Comparison of the hemispheres from deprived rats shows an extension of the whisker representation in the barrel cortex receptive field. CONCLUSIONS: KCSD method showssignificant differences in current sources localization in contralateral to ipsilateral hemisphere. Modular Connectivity Factorization method applied to LFP recordings from simulated data separates cortical column layers into interpretable modules. Physiological interpretation of the results needs further validation on the cortical column model. FINANCIAL SUPPORT: Instytut Biologii Doświadczalnej im. Marcelego Nenckiego Polska Akademia Nauk, Warsaw, Poland, Uniwersytet Warszawski, Warsaw, Poland
7

Focal cortical stroke in the cat visual cortex

51%
Szczerba M., Urban P., Foik A., Kublik E., Ghazaryar A., Borowska J., Sadowska M., Jablonka J., Waleszczyk W.
Acta Neurobiologiae Experimentalis
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2015
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tom 75
|
nr Supl.
BACKGROUNS AND AIMS: The study develops methodology of photothrombotic stroke (PtS) induction in cats visual cortex for future studies of post-stroke visual recovery. Considering its well known organisation and similarity to the human, cat visual system is a good model for spontaneous and supported brain reorganisation after ischemia. METHODS: Photothrombosis was used as a model of focal ischemic cortical stroke. Standardisation of the methodology of cortical PtS was performed on four experimental cats with parallel local field potential (LFP) recordings in and around the stroke core – before, during and after the infarct. Intravenously injected Bengal Rose was locally irradiated by cold light via an optic bundle placed on the skull, thinned skull or directly on dura surface. Different light source parameters and irradiation time were tested. Postoperatively isolated brains were preserved and frozen, cut and stained. Final position of the electrodes was monitored on dried 50 μm slices. The cytochrome oxidase (CO) activity and Nissl staining were used to monitor the state of the tissue injury. RESULTS: The aimed unilateral stroke was performed in the dorsal zone of the left marginal gyrus over the visual cortex on a border of the cortical areas 17 and 18. CO visualizes the areas of lower mitochondrial activity in the illuminated tissue of the irradiated cortex in comparison to the contralateral intact homotopic areas. The spontaneous LFP dynamic decreased for at least three hours within the irradiated cortex but not in opposite hemisphere or surrounding tissue. CONCLUSIONS: The 25 minutes of the unilateral irradiation directly to the dura surface with the light temperature 2750K resulted in the most accurate lesion covering all the width of the marginal gyrus and partially the sulcus area not spreading on adjacent gyri or further blood vessels. The infarct reaches the white matter without its pronounced injury. Supported by:ERA-NET:REVIS&MNiSW0292/IP1/2013/72.
8

Frequency specific changes in signal power and functional conectivity following stroke in the cat visual cortex

51%
Paulina Urban1, Andrzej Foik1, Anaida Ghazaryan1, Anna Popek1, Jan Jabłonka3, Ewa Kublik2, Maciek Kamiński4, Rafał Kuś4, Jarosław Żygierewicz4, Wioletta Waleszczyk1 P., Folk A., Ghazanyan A., Popek A., Jablonka J., Kublik E., Kaminski M., Kus R., Zygierewicz J., Waleszczyk W.
Acta Neurobiologiae Experimentalis
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2015
|
tom 75
|
nr Supl.
AIM: The aim of the study wasto characterize early reorganization of cortical electrical activity within and around the stroke-affected area. METHODS: Photothrombotic stroke wasinduced in the visual cortex during the acute experiments in anaesthetized cats. The activity of neuronal populations (local field potential, LFP) were continuously monitored in the central region of the stroke, at the stroke border, and in the healthy tissue, up to three hours after stroke. In the offline analysis, using Welch and autoregressive parametric methods, we evaluated the changes in the frequency spectrum spanning from delta to gamma. Functional connectivity between cortical locations within and outside the stroke region was determined with Directed Transfer Function (DTF). Indirect and direct interactions in different frequency bands were determined by DTF and direct DTF, respectively. RESULTS: The stroke resulted in an overall decrease of the power within full frequency spectrum in the stroke affected region, but not outside this region, where an increase in the spectral power was observed. The most pronounced changes were observed three hours after the stroke. In one cat, we observed increase of the power in the stroke area in low frequency bands while the power in beta-gamma band was diminished. DTF and direct DTF revealed weakening of neuronal connections between the healthy tissue and the stroke region and a transient strengthening of local connections outside the stroke region. The earliest decrease in the strength of connections in stroke affected region was observed in high frequencies (beta and gamma). CONCLUSION: Stroke induce diverse effects in different frequency bands in both the LFP power spectrum and in the functional connectivity indicating complex influence on the neuronal activity within the stroke and in the vicinity of ischemic region. Supported by ERA-NET Neuron project REVIS.
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