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Dual-compartment neurofluidic system for electrophysiological measurements in physically segregated and functionally connected neuronal cell culture.

Kanagasabapathi TT, Ciliberti D, Martinoia S, Wadman WJ, Decré MM - Front Neuroeng (2011)

Bottom Line: Using electrophysiological measurements of spontaneous network activity in the compartments and selective pharmacological manipulation of cells in one compartment, the biological origin of network activity and the fluidic isolation between the compartments are demonstrated.The connectivity between neuronal populations via the microchannels and the crossing-over of neurites are verified using transfection experiments and immunofluorescence staining.In addition to the neurite cross-over to the adjacent compartment, functional connectivity between cells in both the compartments is verified using cross-correlation (CC) based techniques.

View Article: PubMed Central - PubMed

Affiliation: Minimally Invasive Healthcare Department, Philips Research Laboratories Eindhoven, Netherlands.

ABSTRACT
We developed a dual-compartment neurofluidic system with inter-connecting microchannels to connect neurons from their respective compartments, placed on a planar microelectrode arrays. The design and development of the compartmented microfluidic device for neuronal cell culture, protocol for sustaining long-term cultures, and neurite growth through microchannels in such a closed compartment device are presented. Using electrophysiological measurements of spontaneous network activity in the compartments and selective pharmacological manipulation of cells in one compartment, the biological origin of network activity and the fluidic isolation between the compartments are demonstrated. The connectivity between neuronal populations via the microchannels and the crossing-over of neurites are verified using transfection experiments and immunofluorescence staining. In addition to the neurite cross-over to the adjacent compartment, functional connectivity between cells in both the compartments is verified using cross-correlation (CC) based techniques. Bidirectional signal propagation between the compartments is demonstrated using functional connectivity maps. CC analysis and connectivity maps demonstrate that the two neuronal populations are not only functionally connected within each compartment but also with each other and a well connected functional network was formed between the compartments despite the physical barrier introduced by the microchannels.

No MeSH data available.


Related in: MedlinePlus

Cross-correlation of spontaneous activity in two compartments. (A) Cross-correlograms between a sample electrode in compartment A (Electrode index # 19) and all electrodes in both the compartments; (B) Cross-correlograms with surrogate peak trains in compartment B (between a sample electrode in compartment A (Electrode index # 19) and all electrodes in both the compartments); (C) Comparison of CC between global mean CC averaged over all 60 electrodes (red), mean CC of a sample electrode (Electrode index # 19) with compartment B (green) and CC of most correlated electrodes in both the compartments (Electrode index # 19in compartment A with a sample electrode [(Electrode index # 43) in compartment B (blue)]. Half-window size = 5 ms and Bin size (temporal resolution) = 0.1 ms; (D) Functional connectivity map showing the strongest 100 connections in the network. Red color arrows (intensity coded) represent the functional connections within a compartment; the blue color arrows (intensity coded) represent the functional connectivity between two compartments (inter-compartment connections). Inter-compartment connections are compared with surrogate spike trains and proven to be genuine (Connectivity map with surrogate spike train data not shown). The bidirectionality in network connectivity can be inferred from the direction of the arrows.
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Figure 4: Cross-correlation of spontaneous activity in two compartments. (A) Cross-correlograms between a sample electrode in compartment A (Electrode index # 19) and all electrodes in both the compartments; (B) Cross-correlograms with surrogate peak trains in compartment B (between a sample electrode in compartment A (Electrode index # 19) and all electrodes in both the compartments); (C) Comparison of CC between global mean CC averaged over all 60 electrodes (red), mean CC of a sample electrode (Electrode index # 19) with compartment B (green) and CC of most correlated electrodes in both the compartments (Electrode index # 19in compartment A with a sample electrode [(Electrode index # 43) in compartment B (blue)]. Half-window size = 5 ms and Bin size (temporal resolution) = 0.1 ms; (D) Functional connectivity map showing the strongest 100 connections in the network. Red color arrows (intensity coded) represent the functional connections within a compartment; the blue color arrows (intensity coded) represent the functional connectivity between two compartments (inter-compartment connections). Inter-compartment connections are compared with surrogate spike trains and proven to be genuine (Connectivity map with surrogate spike train data not shown). The bidirectionality in network connectivity can be inferred from the direction of the arrows.

Mentions: As in Figure 1C, synchronized bursting activity is present between the compartments suggesting the existence of coordination in the activity between the two cultured populations. However, in order to bolster the suitability of the device to study the interactions between different neuronal populations, not only structural connectivity but also functional connectivity between the two cultures was investigated. To assess this, we analyzed the CC between individual electrode spike trains. The correlation in the spontaneous activity of all electrodes with respect to a particular electrode was analyzed utilizing CC based methods (Garofalo et al., 2009). Figure 4A shows a sample cross-correlogram obtained during an experimental session, between a sample electrode in compartment A and all the electrodes in both compartments. Autocorrelogram is also included in this case and it corresponds to the maximum peak value. For each couple X → Y (where X = Electrode index 17), the correlograms depict the electrode index (y-axis) and the spike count (z-axis) divided by the time bin of 5 ms, in which electrode X and Y fire a spike with a precise time delay (x-axis). The correlograms when compared with surrogate peak trains in the other compartment showed a significant loss in correlation across the microchannels (Figure 4B).


Dual-compartment neurofluidic system for electrophysiological measurements in physically segregated and functionally connected neuronal cell culture.

Kanagasabapathi TT, Ciliberti D, Martinoia S, Wadman WJ, Decré MM - Front Neuroeng (2011)

Cross-correlation of spontaneous activity in two compartments. (A) Cross-correlograms between a sample electrode in compartment A (Electrode index # 19) and all electrodes in both the compartments; (B) Cross-correlograms with surrogate peak trains in compartment B (between a sample electrode in compartment A (Electrode index # 19) and all electrodes in both the compartments); (C) Comparison of CC between global mean CC averaged over all 60 electrodes (red), mean CC of a sample electrode (Electrode index # 19) with compartment B (green) and CC of most correlated electrodes in both the compartments (Electrode index # 19in compartment A with a sample electrode [(Electrode index # 43) in compartment B (blue)]. Half-window size = 5 ms and Bin size (temporal resolution) = 0.1 ms; (D) Functional connectivity map showing the strongest 100 connections in the network. Red color arrows (intensity coded) represent the functional connections within a compartment; the blue color arrows (intensity coded) represent the functional connectivity between two compartments (inter-compartment connections). Inter-compartment connections are compared with surrogate spike trains and proven to be genuine (Connectivity map with surrogate spike train data not shown). The bidirectionality in network connectivity can be inferred from the direction of the arrows.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3198030&req=5

Figure 4: Cross-correlation of spontaneous activity in two compartments. (A) Cross-correlograms between a sample electrode in compartment A (Electrode index # 19) and all electrodes in both the compartments; (B) Cross-correlograms with surrogate peak trains in compartment B (between a sample electrode in compartment A (Electrode index # 19) and all electrodes in both the compartments); (C) Comparison of CC between global mean CC averaged over all 60 electrodes (red), mean CC of a sample electrode (Electrode index # 19) with compartment B (green) and CC of most correlated electrodes in both the compartments (Electrode index # 19in compartment A with a sample electrode [(Electrode index # 43) in compartment B (blue)]. Half-window size = 5 ms and Bin size (temporal resolution) = 0.1 ms; (D) Functional connectivity map showing the strongest 100 connections in the network. Red color arrows (intensity coded) represent the functional connections within a compartment; the blue color arrows (intensity coded) represent the functional connectivity between two compartments (inter-compartment connections). Inter-compartment connections are compared with surrogate spike trains and proven to be genuine (Connectivity map with surrogate spike train data not shown). The bidirectionality in network connectivity can be inferred from the direction of the arrows.
Mentions: As in Figure 1C, synchronized bursting activity is present between the compartments suggesting the existence of coordination in the activity between the two cultured populations. However, in order to bolster the suitability of the device to study the interactions between different neuronal populations, not only structural connectivity but also functional connectivity between the two cultures was investigated. To assess this, we analyzed the CC between individual electrode spike trains. The correlation in the spontaneous activity of all electrodes with respect to a particular electrode was analyzed utilizing CC based methods (Garofalo et al., 2009). Figure 4A shows a sample cross-correlogram obtained during an experimental session, between a sample electrode in compartment A and all the electrodes in both compartments. Autocorrelogram is also included in this case and it corresponds to the maximum peak value. For each couple X → Y (where X = Electrode index 17), the correlograms depict the electrode index (y-axis) and the spike count (z-axis) divided by the time bin of 5 ms, in which electrode X and Y fire a spike with a precise time delay (x-axis). The correlograms when compared with surrogate peak trains in the other compartment showed a significant loss in correlation across the microchannels (Figure 4B).

Bottom Line: Using electrophysiological measurements of spontaneous network activity in the compartments and selective pharmacological manipulation of cells in one compartment, the biological origin of network activity and the fluidic isolation between the compartments are demonstrated.The connectivity between neuronal populations via the microchannels and the crossing-over of neurites are verified using transfection experiments and immunofluorescence staining.In addition to the neurite cross-over to the adjacent compartment, functional connectivity between cells in both the compartments is verified using cross-correlation (CC) based techniques.

View Article: PubMed Central - PubMed

Affiliation: Minimally Invasive Healthcare Department, Philips Research Laboratories Eindhoven, Netherlands.

ABSTRACT
We developed a dual-compartment neurofluidic system with inter-connecting microchannels to connect neurons from their respective compartments, placed on a planar microelectrode arrays. The design and development of the compartmented microfluidic device for neuronal cell culture, protocol for sustaining long-term cultures, and neurite growth through microchannels in such a closed compartment device are presented. Using electrophysiological measurements of spontaneous network activity in the compartments and selective pharmacological manipulation of cells in one compartment, the biological origin of network activity and the fluidic isolation between the compartments are demonstrated. The connectivity between neuronal populations via the microchannels and the crossing-over of neurites are verified using transfection experiments and immunofluorescence staining. In addition to the neurite cross-over to the adjacent compartment, functional connectivity between cells in both the compartments is verified using cross-correlation (CC) based techniques. Bidirectional signal propagation between the compartments is demonstrated using functional connectivity maps. CC analysis and connectivity maps demonstrate that the two neuronal populations are not only functionally connected within each compartment but also with each other and a well connected functional network was formed between the compartments despite the physical barrier introduced by the microchannels.

No MeSH data available.


Related in: MedlinePlus