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Experimental Investigation on Spontaneously Active Hippocampal Cultures Recorded by Means of High-Density MEAs: Analysis of the Spatial Resolution Effects.

Maccione A, Gandolfo M, Tedesco M, Nieus T, Imfeld K, Martinoia S, Berdondini L - Front Neuroeng (2010)

Bottom Line: Then, the full resolution dataset is spatially downsampled in order to evaluate the effects on raster plot representation, array-wide spike rate (AWSR), mean firing rate (MFR) and mean bursting rate (MBR).Furthermore, the effects of the array-to-network relative position are evaluated by shifting a subset of equally spaced electrodes on the entire recorded area.Results highlight that MFR and MBR are particularly influenced by the spatial resolution provided by the neuroelectronic interface.

View Article: PubMed Central - PubMed

Affiliation: Neuroscience and Brain Technologies, Italian Institute of Technology Genova, Italy.

ABSTRACT
Based on experiments performed with high-resolution Active Pixel Sensor microelectrode arrays (APS-MEAs) coupled with spontaneously active hippocampal cultures, this work investigates the spatial resolution effects of the neuroelectronic interface on the analysis of the recorded electrophysiological signals. The adopted methodology consists, first, in recording the spontaneous activity at the highest spatial resolution (interelectrode separation of 21 mum) from the whole array of 4096 microelectrodes. Then, the full resolution dataset is spatially downsampled in order to evaluate the effects on raster plot representation, array-wide spike rate (AWSR), mean firing rate (MFR) and mean bursting rate (MBR). Furthermore, the effects of the array-to-network relative position are evaluated by shifting a subset of equally spaced electrodes on the entire recorded area. Results highlight that MFR and MBR are particularly influenced by the spatial resolution provided by the neuroelectronic interface. On high-resolution large MEAs, such analysis better represent the time-based parameterization of the network dynamics. Finally, this work suggest interesting capabilities of high-resolution MEAs for spatial-based analysis in dense and low-dense neuronal preparation for investigating signaling at both local and global neuronal circuitries.

No MeSH data available.


Related in: MedlinePlus

Immunofluorescence imaging of a low-density culture at 33 DIVs grown on the active area of an APS-MEA (exp. 8, final density of ∼ 90 cell/mm2) from which the spontaneous activity was recorded. (A-left) Superimposition on the fluorescence image of the detected active electrodes (white squares, spike rate >0.05 spikes/s). (A-right) Close-up on a representative local neuronal circuit from which the electrophysiological extracellular signals reported in (B) were acquired. (B) Raw data acquired from three selected nearby electrodes showing a local propagation from electrode 1 to 3 in about 5 ms.
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Figure 8: Immunofluorescence imaging of a low-density culture at 33 DIVs grown on the active area of an APS-MEA (exp. 8, final density of ∼ 90 cell/mm2) from which the spontaneous activity was recorded. (A-left) Superimposition on the fluorescence image of the detected active electrodes (white squares, spike rate >0.05 spikes/s). (A-right) Close-up on a representative local neuronal circuit from which the electrophysiological extracellular signals reported in (B) were acquired. (B) Raw data acquired from three selected nearby electrodes showing a local propagation from electrode 1 to 3 in about 5 ms.

Mentions: Finally, a direct advantage of MEA-based devices featuring a high spatial resolution is the possibility to address the electrophysiological study of low density neuronal cultures given the higher probability to efficiently couple sparse neuronal networks. These preparations enable to well resolve the network with imaging methods and allow acquiring morphological data (e.g. neurons localizations, neuritis, synaptic connections) to be combined with electrophysiological recordings on high-resolution MEAs. As a preliminary assessment of this feature aimed at correlating the neuronal network topology with its spontaneous electrophysiological functionality, Figure 8A shows an image of the whole APS-MEA active area where a low density culture seeded at 195 cell/mm2 was grown for 33 DIVs. At this developmental stage, the final neuronal density is of ∼90 cell/mm2. As shown, neurons are clearly distinguishable, their spatial distribution is homogeneous, and neurites define a quite complex wiring between the cell bodies. In addition, the figure superimposes with white squares the spontaneously active electrode sites and the well matching between morphological and electrophysiological data can be appreciated. It can be noted that not all the electrodes covered by neurons are detected as active. This is not surprising under the considered spontaneous activity conditions as well as the observation time-window and detection thresholds used in this work.


Experimental Investigation on Spontaneously Active Hippocampal Cultures Recorded by Means of High-Density MEAs: Analysis of the Spatial Resolution Effects.

Maccione A, Gandolfo M, Tedesco M, Nieus T, Imfeld K, Martinoia S, Berdondini L - Front Neuroeng (2010)

Immunofluorescence imaging of a low-density culture at 33 DIVs grown on the active area of an APS-MEA (exp. 8, final density of ∼ 90 cell/mm2) from which the spontaneous activity was recorded. (A-left) Superimposition on the fluorescence image of the detected active electrodes (white squares, spike rate >0.05 spikes/s). (A-right) Close-up on a representative local neuronal circuit from which the electrophysiological extracellular signals reported in (B) were acquired. (B) Raw data acquired from three selected nearby electrodes showing a local propagation from electrode 1 to 3 in about 5 ms.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2871691&req=5

Figure 8: Immunofluorescence imaging of a low-density culture at 33 DIVs grown on the active area of an APS-MEA (exp. 8, final density of ∼ 90 cell/mm2) from which the spontaneous activity was recorded. (A-left) Superimposition on the fluorescence image of the detected active electrodes (white squares, spike rate >0.05 spikes/s). (A-right) Close-up on a representative local neuronal circuit from which the electrophysiological extracellular signals reported in (B) were acquired. (B) Raw data acquired from three selected nearby electrodes showing a local propagation from electrode 1 to 3 in about 5 ms.
Mentions: Finally, a direct advantage of MEA-based devices featuring a high spatial resolution is the possibility to address the electrophysiological study of low density neuronal cultures given the higher probability to efficiently couple sparse neuronal networks. These preparations enable to well resolve the network with imaging methods and allow acquiring morphological data (e.g. neurons localizations, neuritis, synaptic connections) to be combined with electrophysiological recordings on high-resolution MEAs. As a preliminary assessment of this feature aimed at correlating the neuronal network topology with its spontaneous electrophysiological functionality, Figure 8A shows an image of the whole APS-MEA active area where a low density culture seeded at 195 cell/mm2 was grown for 33 DIVs. At this developmental stage, the final neuronal density is of ∼90 cell/mm2. As shown, neurons are clearly distinguishable, their spatial distribution is homogeneous, and neurites define a quite complex wiring between the cell bodies. In addition, the figure superimposes with white squares the spontaneously active electrode sites and the well matching between morphological and electrophysiological data can be appreciated. It can be noted that not all the electrodes covered by neurons are detected as active. This is not surprising under the considered spontaneous activity conditions as well as the observation time-window and detection thresholds used in this work.

Bottom Line: Then, the full resolution dataset is spatially downsampled in order to evaluate the effects on raster plot representation, array-wide spike rate (AWSR), mean firing rate (MFR) and mean bursting rate (MBR).Furthermore, the effects of the array-to-network relative position are evaluated by shifting a subset of equally spaced electrodes on the entire recorded area.Results highlight that MFR and MBR are particularly influenced by the spatial resolution provided by the neuroelectronic interface.

View Article: PubMed Central - PubMed

Affiliation: Neuroscience and Brain Technologies, Italian Institute of Technology Genova, Italy.

ABSTRACT
Based on experiments performed with high-resolution Active Pixel Sensor microelectrode arrays (APS-MEAs) coupled with spontaneously active hippocampal cultures, this work investigates the spatial resolution effects of the neuroelectronic interface on the analysis of the recorded electrophysiological signals. The adopted methodology consists, first, in recording the spontaneous activity at the highest spatial resolution (interelectrode separation of 21 mum) from the whole array of 4096 microelectrodes. Then, the full resolution dataset is spatially downsampled in order to evaluate the effects on raster plot representation, array-wide spike rate (AWSR), mean firing rate (MFR) and mean bursting rate (MBR). Furthermore, the effects of the array-to-network relative position are evaluated by shifting a subset of equally spaced electrodes on the entire recorded area. Results highlight that MFR and MBR are particularly influenced by the spatial resolution provided by the neuroelectronic interface. On high-resolution large MEAs, such analysis better represent the time-based parameterization of the network dynamics. Finally, this work suggest interesting capabilities of high-resolution MEAs for spatial-based analysis in dense and low-dense neuronal preparation for investigating signaling at both local and global neuronal circuitries.

No MeSH data available.


Related in: MedlinePlus