Morphological reconstruction of the 3rd instar aCC motoneuron.

<p>(<b>A</b>) Schematic muscle projections of aCC motoneurons based on their location in the nerve cord segment. (<b>B</b>) Stack of microscope images was reconstructed using Amira software (Visage Imaging GmbH, Berlin, Germany) and then imported into the Neuron simulator [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004189#pcbi.1004189.ref072" target="_blank">72</a>]. The rightmost schema indicates the major morphological components in an idealized depiction. “ext. axon” indicates the missing extended axon from the reconstruction (not drawn to scale). (<b>C</b>) Equivalent circuit of the measured passive properties including an electrode model for voltage clamp. (<b>D</b>) Passive response to voltage-clamp step to −90 mV from a holding potential of −60 mV is simulated in Neuron with the fitted parameters (see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004189#pcbi.1004189.t002" target="_blank">Table 2</a>).</p

Other parameters varied to obtain realistic firing activity from morphological models with different NaT-Ks channel distributions.

<p>Recon: reconstructed; elec: electrode.</p><p>Other parameters varied to obtain realistic firing activity from morphological models with different NaT-Ks channel distributions.</p

NaT sodium current component was filtered more than NaP in the simulated morphology.

<p>(<b>A</b>) Total axial sodium currents (top) recorded at several color-coded locations on the main neurite (axon) in response to voltage clamp. Voltage traces of the selected locations (bottom) showed that the quality of voltage clamp weakens distally. Model NaP (<b>B</b>) and NaT (<b>C</b>) current components recorded where they originated in the extended axon SIZ segment for in the original model (black), in models where the NaT (green) or NaP (blue) component was increased 5-fold. (<b>D</b>) Clamp currents recorded at the soma for the same three conditions and in a model where the SIZ was 20 μm closer to the soma (50 μm).</p

Different distributions of NaT/Ks channels on the constructed morphology predicted SIZ location that can reproduce firing activity characteristics.

<p>(<b>A</b>-<b>C</b>) Skeletal model reconstructions showing high density of NaT/Ks channels in red. (<b>D</b>) Axon extension with NaT/Ks channels placed on the distal segment. (<b>F</b>-<b>I</b>) Simulated responses to the three-step current clamp of each model corresponding to channel distributions in panels A-D. (<b>E</b>, <b>J</b>) Morphology and recorded responses of aCC to same input current levels, repeated from <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004189#pcbi.1004189.g002" target="_blank">Fig 2Ai</a> for comparison. Change of voltage offset (<b>K</b>) and spike amplitude (<b>L</b>) with current injection compared between the NaT/Ks placements in (<b>A</b>-<b>D</b>) and the biological recording (aCC w/ Cd²⁺).</p

Morphology passive parameters fitted to 3rd instar aCC responses to passive voltage clamp protocol recordings (<i>n</i> = 5).

<p>Morphology passive parameters fitted to 3rd instar aCC responses to passive voltage clamp protocol recordings (<i>n</i> = 5).</p

Symmetry of voltage attenuation in the morphology.

<p>Each row indicates a morphological location for which we simulated the ratio of voltage amplitude at measurement site over voltage at current injection site for two conditions: injecting distally and measuring at somatic electrode (elec), and injecting at the electrode and measuring distally (distal). Experiments were repeated for direct current (DC, 0 Hz) and high frequency (sinusoidal, 100 Hz) stimuli. In addition to the two dendritic locations (dend1 & 2) in the ipsilateral arbor shown in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004189#pcbi.1004189.g004" target="_blank">Fig 4A</a>, we also tested the distal-most tip of the contralateral dendritic arbor (contra tip) and the spike initiation zone (SIZ—see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004189#pcbi.1004189.g006" target="_blank">Fig 6D</a>).</p><p>Symmetry of voltage attenuation in the morphology.</p

Isopotential and two-compartment models compared to recordings.

<p>(<b>A</b>) Third instar aCC motoneuron recording (i.) in presence of 0.2 mM Cd⁺² to block Ca⁺² channels missing from models. Voltage response to three current injection levels. Isopotential (ii.) and two-compartment (iii.) models’ voltage responses to same current injection. (<b>B</b>) Recorded and simulated firing responses to current injection were similar. Firing rate was calculated as the inverse of mean interspike interval (ISI). iso-model: isopotential model; 2c-model: two-compartment model. (<b>C</b>) Models also approximated aCC motoneuron delay to first spike in response to current injection. (<b>D</b>) The firing rate-membrane voltage (f-V) response of only the two-compartment model qualitatively mimicked the inter-spike voltage depolarizations that appeared for high firing rates.</p

Simulations of the passive morphology showed its compactness and filtering properties.

<p>(<b>A</b>) Simulation setup for the ipsilateral dendritic field of the reconstructed morphology (thick line is the primary neurite), where a 50 pA current clamp (CC) stimulus was applied at the model electrode compartment. (<b>B</b>) Voltage across model morphology locations marked in panel <b>A</b> in response to the current stimulus. (<b>C</b>) Electrotonic structure of the morphology compared at different stimulus frequencies. Lambda scale bar shows one length constant, at which voltage changes to about 37% of its initial value. For a step input (0 Hz), the length constant was several times larger than the arbor size, meaning voltages will travel across the arbor unimpeded. At a higher input frequency of 100 Hz, the span across the morphology was larger than one electrotonic length. (<b>D</b>) Ionic-like currents were simulated on the passive morphology by varying current injection location and responses were recorded holding the soma in voltage clamp at -60 mV. (<b>E</b>) Voltage clamp current evoked in response to exponentially decaying stimulus of 2 nA magnitude and 2 ms time constant injected at six locations in panel <b>A</b> starting at the electrode, and numbered in aquamarine as they went distally. (<b>F</b>) When same stimulus is injected at middle of compartment axon (prox), compartments far from the electrode escaped from the voltage clamp to various degrees. (<b>G</b>) By varying the time-constant of the same exponentially decaying stimulus applied to a fixed location axon (prox) in simulated morphology, we showed that the membrane response is filtered dependent on frequency. Dashed gray line shows the fastest (<i>τ</i> = 0.3 ms) current stimulus applied distally.</p

Graphene Anodes and Cathodes: Tuning the Work Function of Graphene by Nearly 2 eV with an Aqueous Intercalation Process

To expand the applications of graphene in optoelectronics and microelectronics, simple and effective doping processes need to be developed. In this paper, we demonstrate an aqueous process that can simultaneously transfer chemical vapor deposition grown graphene from Cu to other substrates and produce stacked graphene/dopant intercalation films with tunable work functions, which differs significantly from conventional doping methods using vacuum evaporation or spin-coating processes. The work function of graphene layers can be tuned from 3.25 to 5.10 eV, which practically covers the wide range of the anode and cathode applications. Doped graphene films in intercalation structures also exhibit excellent transparency and low resistance. The polymer-based solar cells with either low work function graphene as cathodes or high work function graphene as anodes are demonstrated

Malformation of the cranial cartilages of hypo-Q/R-editing morphants.

<p>Representative images of Alcian blue staining of the head cartilages are presented in three views. Ventral view is taken at a deeper focus from the dorsal side. Abbreviations: bh, basihyal; cb, ceratobranchials; ch, ceratohyal; ep, ethmoid plate; hs, hyosymplectic; m, Meckel's cartilage; not, notochord; pch, parachordal; pq, palatoquadrate; tr, trabeculae.</p