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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

(A) Layouts representation corresponding to the electrode subsets and used for analyzing the data at different spatial-scales. (top) Entire active area of an APS-MEA (2.7 × 2.7 mm2) arranged in a 64 × 64 layout. (bottom) The electrode array subsets are defined by considering a constant active area of 1.7 × 1.7 mm2. The lowest electrode density is of 19 electrode/mm2 for the 60 electrodes layout, and values gradually scale up to the full resolution configuration at 580 electrode/mm2 for the 1849 electrodes layout. (B) Subset of 60 channels at different positions with respect to the entire active area. The different layouts are moved within an equivalent electrode area integrating 580 electrode/mm2.
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Figure 2: (A) Layouts representation corresponding to the electrode subsets and used for analyzing the data at different spatial-scales. (top) Entire active area of an APS-MEA (2.7 × 2.7 mm2) arranged in a 64 × 64 layout. (bottom) The electrode array subsets are defined by considering a constant active area of 1.7 × 1.7 mm2. The lowest electrode density is of 19 electrode/mm2 for the 60 electrodes layout, and values gradually scale up to the full resolution configuration at 580 electrode/mm2 for the 1849 electrodes layout. (B) Subset of 60 channels at different positions with respect to the entire active area. The different layouts are moved within an equivalent electrode area integrating 580 electrode/mm2.

Mentions: In order to compare analysis results at different spatial resolutions, we extracted from the full resolution recording, subsets of electrodes at different spatial densities while maintaining a constant active area for the so defined layouts. This area (i.e. 1.7 × 1.7 mm2) was defined in order to be also comparable with a commercially available device (MEA200-30, from Multichannel Systems) even if it is smaller compared to the active area provided by the whole APS-MEAs (2.7 × 2.7 mm2). As shown in Figure 2A, starting with a subset of 60 electrodes (layout A – interelectrode distance of 189 μm, electrode density of 19 electrode/mm2) comparable with the same commercially available MEA (interelectrode distance of 170 μm), we gradually increased the number of electrodes and thus the electrode densities (layout B – 109 electrodes and electrode density of 34 electrode/mm2, layout C – 221 electrodes and electrode density of 69 electrode/mm2, layout D – 480 electrodes and electrode density of 151 electrode/mm2, layout E – 921 electrodes and electrode density of 289 electrode/mm2) up to the full resolution provided by the APS-MEA chip (layout F – 1849 electrodes and electrode density of 580 electrode/mm2). These data were then analyzed as they were distinct MEA layouts randomly coupled with the same neuronal network. The analysis of the spontaneous activity consisted in performing the spikes and bursts detection and in computing from the active electrode's signals (firing rate >0.05 spike/s), the Array-Wide Spike Rate (AWSR), i.e. the number of spike/s summed over all channels, the MBR and the MFR, with a bin size of 10 ms. Since all array layouts share the same original high-resolution recording, it was then possible to evaluate the effects of the electrode density on the analysis parameters by plotting the results in respect to the electrode densities and to the array-network relative positions. Indeed, the relative position effect was evaluated by moving the layout of 60 electrodes as sketched in Figure 2B. A total of five different positions were considered, the MFRs were computed and then compared with the results obtained by considering the same positions but with a high density layout of 580 electrode/mm2 as in Figure 2A-f.


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)

(A) Layouts representation corresponding to the electrode subsets and used for analyzing the data at different spatial-scales. (top) Entire active area of an APS-MEA (2.7 × 2.7 mm2) arranged in a 64 × 64 layout. (bottom) The electrode array subsets are defined by considering a constant active area of 1.7 × 1.7 mm2. The lowest electrode density is of 19 electrode/mm2 for the 60 electrodes layout, and values gradually scale up to the full resolution configuration at 580 electrode/mm2 for the 1849 electrodes layout. (B) Subset of 60 channels at different positions with respect to the entire active area. The different layouts are moved within an equivalent electrode area integrating 580 electrode/mm2.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: (A) Layouts representation corresponding to the electrode subsets and used for analyzing the data at different spatial-scales. (top) Entire active area of an APS-MEA (2.7 × 2.7 mm2) arranged in a 64 × 64 layout. (bottom) The electrode array subsets are defined by considering a constant active area of 1.7 × 1.7 mm2. The lowest electrode density is of 19 electrode/mm2 for the 60 electrodes layout, and values gradually scale up to the full resolution configuration at 580 electrode/mm2 for the 1849 electrodes layout. (B) Subset of 60 channels at different positions with respect to the entire active area. The different layouts are moved within an equivalent electrode area integrating 580 electrode/mm2.
Mentions: In order to compare analysis results at different spatial resolutions, we extracted from the full resolution recording, subsets of electrodes at different spatial densities while maintaining a constant active area for the so defined layouts. This area (i.e. 1.7 × 1.7 mm2) was defined in order to be also comparable with a commercially available device (MEA200-30, from Multichannel Systems) even if it is smaller compared to the active area provided by the whole APS-MEAs (2.7 × 2.7 mm2). As shown in Figure 2A, starting with a subset of 60 electrodes (layout A – interelectrode distance of 189 μm, electrode density of 19 electrode/mm2) comparable with the same commercially available MEA (interelectrode distance of 170 μm), we gradually increased the number of electrodes and thus the electrode densities (layout B – 109 electrodes and electrode density of 34 electrode/mm2, layout C – 221 electrodes and electrode density of 69 electrode/mm2, layout D – 480 electrodes and electrode density of 151 electrode/mm2, layout E – 921 electrodes and electrode density of 289 electrode/mm2) up to the full resolution provided by the APS-MEA chip (layout F – 1849 electrodes and electrode density of 580 electrode/mm2). These data were then analyzed as they were distinct MEA layouts randomly coupled with the same neuronal network. The analysis of the spontaneous activity consisted in performing the spikes and bursts detection and in computing from the active electrode's signals (firing rate >0.05 spike/s), the Array-Wide Spike Rate (AWSR), i.e. the number of spike/s summed over all channels, the MBR and the MFR, with a bin size of 10 ms. Since all array layouts share the same original high-resolution recording, it was then possible to evaluate the effects of the electrode density on the analysis parameters by plotting the results in respect to the electrode densities and to the array-network relative positions. Indeed, the relative position effect was evaluated by moving the layout of 60 electrodes as sketched in Figure 2B. A total of five different positions were considered, the MFRs were computed and then compared with the results obtained by considering the same positions but with a high density layout of 580 electrode/mm2 as in Figure 2A-f.

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