Figure 1. Origins of the Ball and Chain model of fast inactivation. (A) Sodium current of squid giant axon before (black) and after pronase treatment (red) for a depolarization to 0 mV from a holding potential of −70 mV. The initial outward More about this image found in Origins of the Ball and Chain model of fast inactivation. (A) Sodium curre...

Figure 2. Voltage sensor dynamics and the hinged-lid model of fast inactivation. (A) Secondary structure of Nav1.4 showing the four domains and the six transmembrane segments of each domain. The stars indicate the positions of the fluorophores More about this image found in Voltage sensor dynamics and the hinged-lid model of fast inactivation. (A) ...

Figure 3. Structural identification of the hydrophobic gate underlying fast inactivation. (A) View of the position of the hydrophobic gate residues in the pore of the sodium channel (in dark blue) and the location of the IFM motif (in red). More about this image found in Structural identification of the hydrophobic gate underlying fast inactivat...

Figure 4. The IFM motif links DIV VSD activation to inactivation gate. (A) Upon depolarization, DIV VSD (not shown for simplicity) activates and due to its slow kinetics, manifests as the slow component in the gating current. (B) Activation of More about this image found in The IFM motif links DIV VSD activation to inactivation gate. (A) Upon depo...

Figure 5. Structural components and interactions involved in fast inactivation. (A) Hydrogen bonds couple the DIV VSD and DIII–DIV linker movements. Two hydrogen bonds are identified: N1477 (DIV S4–S5 linker, in orange) with F1304 (IFM motif, in More about this image found in Structural components and interactions involved in fast inactivation. (A) ...

Figure 6. States and events that lead to inactivation: the lock and key model. (A) This sequence starts after the VSDs of the first three domains have moved and the channel has opened, as indicated by the early part of the inward Na current (the More about this image found in States and events that lead to inactivation: the lock and key model. (A) T...

Figure 1. Extracellular recording setup and circuit diagram of electrosensory pathways. (A) Extracellular recordings from ELL pyramidal cells were made using high-density arrays, and the spikes were sorted using standard techniques. (B) More about this image found in Extracellular recording setup and circuit diagram of electrosensory pathway...

Figure 2. ELL pyramidal cells display heterogeneous spiking activities in vivo. (A) Raster plot illustrating the spiking activities of 18 representative ELL pyramidal cells sorted from highest to lowest mean firing rate. (B) ISI probability More about this image found in ELL pyramidal cells display heterogeneous spiking activities in viv...

Figure 3. A conductance-based computational model reproduces membrane potential traces and Ca ²⁺ fluctuations as seen in vivo. (A) Schematic of the model highlighting the two compartments of the cell: soma and dendritic tree with the various More about this image found in A conductance-based computational model reproduces membrane potential trace...

Figure 4. Model-generated ISI distributions recapitulate the heterogeneous spiking patterns observed in ELL pyramidal cell populations. (A) Schematic showing the algorithm used to fit the model to each ELL pyramidal cell. A maximum likelihood More about this image found in Model-generated ISI distributions recapitulate the heterogeneous spiking pa...

Figure 5. Extrinsic synaptic input parameters exhibit the largest heterogeneity among the fitted model parameters across the ELL pyramidal cell population. (A) Violin plots showing the distributions of normalized pairwise distances for the six More about this image found in Extrinsic synaptic input parameters exhibit the largest heterogeneity among...

Figure 6. Pharmacological inactivation of feedback pathways strongly alters ELL pyramidal cell spiking activities. (A) Simplified diagram of feedforward (black) and feedback (orange) electrosensory pathways. Pharmacological inactivation of More about this image found in Pharmacological inactivation of feedback pathways strongly alters ELL pyram...

Figure 7. The model captures parameter changes associated with reduced extrinsic synaptic input during feedback inactivation. (A) Violin plots showing distributions of pairwise distances before (blue, left) and after (orange, right) More about this image found in The model captures parameter changes associated with reduced extrinsic syna...

Figure 8. Exogenous serotonin application alters spiking statistics and increases firing heterogeneity in ELL pyramidal cells. (A) Simplified diagram of feedforward (black) and feedback (orange) electrosensory pathways. Serotonin was applied More about this image found in Exogenous serotonin application alters spiking statistics and increases fir...

Figure 9. The model captures changes in intrinsic and extrinsic parameters following exogenous serotonin application. (A) Violin plots showing distributions of pairwise distances before (blue, left) and after (orange, right) serotonin More about this image found in The model captures changes in intrinsic and extrinsic parameters following ...

Gucan Dai and Lucas Handlin. Gucan Dai and Lucas Handlin stand in a laboratory setting, smiling at the camera. More about this image found in Gucan Dai and Lucas Handlin. Gucan Dai and Lucas Handlin stand in a labo...