Solutions of sodium bicarbonate, calcium chloride, ethanol, acetic acid, and methanol, in concentrations ranging from 10−7 to 0.1 molar, were frozen under controlled conditions to measure the dependence of ice-spike formation on chemical impurities in water. The probability of ice-spike formation was plotted against molarity of solution to determine general trends for different solutes. The var...

Action potentials (APs) in the mammalian brain are thought to represent the smallest unit of information transmitted by neurons to their postsynaptic targets. According to this view, neuronal signaling is all-or-none or digital. Increasing evidence suggests, however, that subthreshold changes in presynaptic membrane potential before triggering the spike also determines spike-evoked release of n...

Decrease of the sodium concentration of the medium depresses both the spike and the associated impedance change in almost identical fashion. Elevation of the potassium level also depresses both phenomena, but affects the impedance change more than the spike; it slows the return to the initial impedance level. The effects on the threshold to brief square waves are also described. These results a...

We explain the mechanism that elicits the mixed mode oscillations (MMOs) and the subprimary firing range that we recently discovered in mouse spinal motoneurons. In this firing regime, high-frequency subthreshold oscillations appear a few millivolts below the spike voltage threshold and precede the firing of a full blown spike. By combining intracellular recordings in vivo (including dynamic cl...

Pyramidal cells of the electrosensory lateral line lobe (ELL) of the weakly electric fish Apteronotus leptorhynchus have been shown to produce oscillatory burst discharge in the gamma-frequency range (20-80 Hz) in response to constant depolarizing stimuli. Previous in vitro studies have shown that these bursts arise through a recurring spike backpropagation from soma to apical dendrites that is...

The membrane potential of the longitudinal muscle of the earthworm is only — 35 mV. and this value is much lower than those of the Loligo giant fibres (— 60 mV.), frog striated muscle ( — 90 mV.) and mammalian smooth muscle ( — 50 mV.). The difference in the membrane potential might suggest a specificity in the ionic distribution or ionic permeability in the longitudinal muscle of the earthworm...

Spike timing reliability of neuronal responses depends on the frequency content of the input. We investigate how intrinsic properties of cortical neurons affect spike timing reliability in response to rhythmic inputs of suprathreshold mean. Analyzing reliability of conductance-based cortical model neurons on the basis of a correlation measure, we show two aspects of how ionic conductances influ...

In crustacean muscle, earthworm longitudinal muscle, leech longitudinal muscle and barnacle muscle the major role in the production of the action potential is played by divalent cations rather than sodium ions, which are believed to be most important in many other excitable cells (Fatt & Ginsborg, 1958; Fatt & Katz, 1953; Werman, McCann & Grundfest, 1961; Hagiwara, Chichibu & Naka, 1964; Hagiwa...

Voltage-dependent membrane conductances support specific neurophysiological properties. To investigate the mechanisms of coincidence detection, we activated gerbil medial superior olivary (MSO) neurons with dynamic current-clamp stimuli in vitro. Spike-triggered reverse-correlation analysis for injected current was used to evaluate the integration of subthreshold noisy signals. Consistent with ...