Wyniki wyszukiwania

1

Dissecting activity of individual cell populations with kernel current source density method and independent components analysis

100%

Wojcik D. K., Potworowski J., Glabska H., Leski S.

Acta Neurobiologiae Experimentalis

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2012

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tom 72

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nr 2

Local field potentials (LFP), the low-frequency part of extracellular electric potential, reflect dendritic processing of synaptic inputs to neuronal populations. Today one can easily record simultaneous potentials from multiple contacts. Due to the nature of electric field each electrode may record activity of sources millimeters away which leads to significant correlations between signals and complicates their analysis. Whenever possible it is convenient to estimate the current source density (CSD), the volume density of net transmembrane currents, which generate the LFP. CSD directly reflects the local neural activity and CSD analysis is often used to analyze LFP. We present here a general, nonparametric method for CSD estimation based on kernel techniques, which can take into account known anatomy or physiology of the studied structure. Using data from a simulated large scale model of thalamo-cortical column we also show how CSD analysis combined with independent component analysis (ICA) can reveal information on activity of individual cell populations. Research supported by grants 5428/B/P01/2010/39, POIG.02.03.00- 00-003/09, POIG.02.03.00-00-018/08.

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Separating dynamics of different cell populations from multielectrode signals

88%

Wojcik D., Potworowski J., Glabska H., Majka P., Leski S.

Acta Neurobiologiae Experimentalis

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2011

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tom 71

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nr S

Local field potentials (LFP), low-frequency part of extracellular electric potentials, seem to reflect dendritic processing of incoming activity to neural populations. Long-range nature of electric field leads to correlations even between remote recordings showing sources from millimeters away which complicates analysis of LFP. To get more insight it is convenient whenever possible to look for current sources of the potentials or to decompose the signals into meaningful components using statistical techniques. In Łęski and coauthors (2010) we have combined inverse current source density method with independent component analysis (ICA) to decompose 140 recordings in rat forebrain obtaining physiologically meaningful components across a group of seven animals. To find out what can be really observed with such an approach experimentally we simulated local field potentials generated in a single cortical column in a model of 3560 cells with non-trivial morphologies. Having both the current source density (CSD) and LFP generated by twelve cortical populations included we compared it with independent components obtained in the decomposition of data generated by the whole network. We assumed a set of potential measurements on a regular grid, low-pass filtered it temporally under 500 Hz, reconstructed the sources using kernel current source density and performed the ICA. We found that the recorded evoked activity was dominated by two populations of pyramidal neurons, which were well separated by ICA. Other populations could not be clearly distinguished in the simulated potentials nor in the ICA. Supported by grants POIG.02.03.00-00-003/09, POIG.02.03.00-00-018/08.

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Simulations of local field potentials and current source density analysis in slices with realistic conductivity distribution

76%

Wojcik D. K., Ness T. B., Chintaluri H. C., Potworowski J., Gabska H., Leski S., Einevoll G. T.

Acta Neurobiologiae Experimentalis

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2013

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tom 73

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nr Suppl.1

To test methods of local field potential (LFP) analysis we need realistic ground truth data which demands plausible models of neural activity and of physical properties of the setup, tissue, and the electrodes. To interpret the recordings we often reconstruct the Current Source Density (CSD) from the LFP. In this work we study the effect of realistic conductivity profiles and the slice geometry on (1) computation of LFP generated by cell populations embedded in slice, as would be measured on multi-electrode array (MEA), and (2) current source density (CSD) reconstruction in the slice from such potentials. We show that the method of images approximates solution through finite elements well while being much more efficient computationally. Inclusion of slice properties with homogeneous and uniform conductivity in the slice noticeably modifies the observed activity (LFP) but inhomogeneity and anisotropy do not further change the profile and amplitude of the LFP. Supported with grants: IP2011 030971, N N303 542839, FP7-PEOPLE-2010-ITN 264872, POIG.02.03.00-00-018/08, POIG.02.03.00-00-003/09.

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Lack of strong cortical impact on the somatosensory evoked potentials recorded in the rat thalamus

76%

Borzymowska Z., Potworowski J., Kaminski J., Wrobel A., Wojcik D., Kublik E.

Acta Neurobiologiae Experimentalis

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2013

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tom 73

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nr 4

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The sources of local field potentials recorded along thalamo-cortical part of somatosensory path way in a rat

76%

Borzymowska Z., Potworowski J., Kaminski J., Wrobel A., Wojcik D., Kublik E.

Acta Neurobiologiae Experimentalis

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2013

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tom 73

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nr Suppl.1

Local field potentials recording is a tool well suited for the chronic monitoring of neuronal activity. However, due to the widespread propagation of electric field within a brain tissue a signal recorded in one place may possess a substantial contribution of synaptic currents from distant neuronal populations. In the rat vibrissae-barrel system the cortical representation of mystacial vibrissae is located closely above their somatosensory relays in thalamic nuclei. Since the order and dynamics of thalamic EP waves resemble those of cortical ones, it is crucial to determine to what extent these signals are generated locally or whether they reflect the electrotonic component from cortical sources and vice versa. Using two linear multielectrodes (100 µm inter-electrode distances) we recorded series of potentials evoked by deflections of a group of vibrissae, thus obtaining EP profile spanning the tissue from the cortical surface to the level below somatosensory thalamic nuclei. Kernel Current-Source Density analysis revealed that the subcortical EPs recorded in the external capsule and fimbria of the hippocampus comprised mostly of responses of cortical characteristics while those recorded within the thalamus mainly possessed components characteristic to the local, thalamic sources. Research supported by the polish National Science Centre grant N N401 533040.

Ograniczanie wyników

5 Acta Neurobiologiae Experimentalis

5 Potworowski J.

3 Leski S.

3 Wojcik D.

2 Borzymowska Z.

2 Glabska H.

2 Kaminski J.

2 Kublik E.

2 Wojcik D. K.

2 Wrobel A.

1 Chintaluri H. C.

1 Einevoll G. T.

1 Gabska H.

1 Majka P.

1 Ness T. B.

3 2013

1 2012

1 2011

Dissecting activity of individual cell populations with kernel current source density method and independent components analysis

Separating dynamics of different cell populations from multielectrode signals

Simulations of local field potentials and current source density analysis in slices with realistic conductivity distribution

Lack of strong cortical impact on the somatosensory evoked potentials recorded in the rat thalamus

The sources of local field potentials recorded along thalamo-cortical part of somatosensory path way in a rat