Dot display of a characteristic network bursting phase in a simultaneous MEA and patch-clamp recording. ( APs on MEA channels (1-60), and APs on intracellular channels (61-62), | detected burst onsets). 

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... tailor the surface chemistry of glass slides and MEAs we used a surface-immobilized benzophenone derivative, which can be attached to any alkyl group photo-chemically (Figure 1) [1]. These surfaces were modified by attaching hydrophilic (poly(dimethyl acrylamide) -PDMAAm), hydrophobic (poly(methyl methacrylate) -PMMA, polystyrene -PS), ultra- hydrophobic (fluoropolymer -FP), and positively charged (poly(ethylene imine) -PEI) polymers (for detailed polymer synthesis see [2]). Adhesion and outgrowth of neurons were studied in a serum con- taining medium. Dissociated neuronal cells from neo- natal rat cortex (for details see [3]) were seeded onto the polymer coatings and incubated for several weeks. The number of adherent cells was reduced and the neuronal network morphology was degraded on the FP, PMMA, and PS coatings (indicated by clustering of cell somata). PEI (Figure 2, A) supported the initial adhesion of neurons forming a uniform neuronal net- work within three days in vitro. In contrast, neurons never adhered on PDMAAm (Figure 2, B). 2 Guidance of neuronal cells on pat- terned polymer ...

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... tailor the surface chemistry of glass slides and MEAs we used a surface-immobilized benzophenone derivative, which can be attached to any alkyl group photo-chemically (Figure 1) [1]. These surfaces were modified by attaching hydrophilic (poly(dimethyl acrylamide) -PDMAAm), hydrophobic (poly(methyl methacrylate) -PMMA, polystyrene -PS), ultra- hydrophobic (fluoropolymer -FP), and positively charged (poly(ethylene imine) -PEI) polymers (for detailed polymer synthesis see [2]). Adhesion and outgrowth of neurons were studied in a serum con- taining medium. Dissociated neuronal cells from neo- natal rat cortex (for details see [3]) were seeded onto the polymer coatings and incubated for several weeks. The number of adherent cells was reduced and the neuronal network morphology was degraded on the FP, PMMA, and PS coatings (indicated by clustering of cell somata). PEI (Figure 2, A) supported the initial adhesion of neurons forming a uniform neuronal net- work within three days in vitro. In contrast, neurons never adhered on PDMAAm (Figure 2, B). 2 Guidance of neuronal cells on pat- terned polymer ...

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... fields were characterized with a modi- fied Scholl analysis (Scholl, 1953) describing the ra- dial dendritic field density of neurons. To account for the overlap of dendritic fields of spatially non- uniformly distributed neurons and for the influence of neuronal neighborhood relations on neuritic differen- tiation, neurons were grouped into classes of compa- rable local neuron density. For this we determined the number of neighboring neurons within a range of 100µm according to a measure for spatial clustering (Prodanov, 2007). Blocking PKC activity significantly enhanced maximal radial dendritic arborization up to +20% at intermediate (DIV14) and about +75% at later stages (DIV40) of development (Fig. 3). Typi- cally, neurite density decreased in untreated cultures but slightly increased with PKC inhibition between DIV14 and DIV40. This suggests that blocking PKC activity prevents pruning and prolongs the neurite elongation phase. Neurons in sparse cultures with negligible dendrite field overlap were traced manually and likewise showed significantly enhanced dendritic field extents under PKC inhibition at DIV14 (Fig ...

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... by network bursts After 'random' stimulation, responses were ex- tracted according to the criteria for single-electrode bursts. Stimulation trials were sorted for increasing response length (in seconds). Pre-stimulus activity and response lengths were inversely correlated: high burst- ing activity immediately preceded short responses, periods of no or low bursting activity preceded long responses (Fig. 2a). Quantitative analysis, including examples from different networks shown in Fig. 2b. This effect was most clearly observed when stimula- tion elicited long-and short-term responses, as well as when the activity did not (yet) develop into Super- ...

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... by network bursts After 'random' stimulation, responses were ex- tracted according to the criteria for single-electrode bursts. Stimulation trials were sorted for increasing response length (in seconds). Pre-stimulus activity and response lengths were inversely correlated: high burst- ing activity immediately preceded short responses, periods of no or low bursting activity preceded long responses (Fig. 2a). Quantitative analysis, including examples from different networks shown in Fig. 2b. This effect was most clearly observed when stimula- tion elicited long-and short-term responses, as well as when the activity did not (yet) develop into Super- ...

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... activity was almost exclusively com- prised of synchronous network events. Individual cul- tures displayed subsets of bursts that had spatiotempo- ral patterns such as shorter bursts or phases of high- frequent bursting (Fig. 2). The resting membrane potentials of the analyzed neurons (n=92) ranged from -46.2 mV to -78.3 mV (mean=-61.9 mV). A holding potential of -50 to -60 mV was applied to neurons with resting potential above -50 mV. The time constants ranged from 5.7 ms to 33.4 ms (mean=16.4 ms). Normal input-frequency properties were found for the analyzed neurons (data not ...