A firing-rate model of spike-frequency adaptation in sinusoidally-driven thalamocortical relay neurons

2001 ◽  
Vol 1 (02) ◽  
pp. 135 ◽  
Author(s):  
Gregory D. Smith ◽  
Charles L. Cox ◽  
Murray S. Sherman ◽  
John Rinzel
Keyword(s):  
Firing Rate ◽  
Spike Frequency ◽  
Spike Frequency Adaptation ◽  
Rate Model ◽  
Frequency Adaptation ◽  
Relay Neurons

scholarly journals Slow Spike Frequency Adaptation in Neurons of the Rat Subthalamic Nucleus

2009 ◽  
Vol 102 (6) ◽  
pp. 3689-3697 ◽  
Author(s):  
David Barraza ◽  
Hitoshi Kita ◽  
Charles J. Wilson
Keyword(s):  
Firing Rate ◽  
Subthalamic Nucleus ◽  
Similar Rate ◽  
Excitatory Input ◽  
Spike Frequency ◽  
Spike Frequency Adaptation ◽  
Frequency Adaptation ◽  
Long Duration ◽  
Subthalamic Neurons

Neurons of the subthalamic nucleus (STN) are very sensitive to applied currents, firing at 10–20/s during spontaneous activity, but increasing to peak firing rates of 200/s with applied currents <0.5 nA. They receive a powerful tonic excitatory input from neurons in the cerebral cortex, yet in vivo maintain an irregular firing rate only slightly higher than the autonomous firing rate seen in slices. Spike frequency adaptation acts to normalize background firing rate by removing slow trends in firing due to changes in average input. Subthalamic neurons have been previously described as showing little spike frequency adaptation, but this was based on tests using brief stimuli. We applied long-duration depolarizing current steps to STN neurons in slices and observed a very strong spike frequency adaptation with a time constant of 20 s and that recovered at a similar rate. This adaptation could return firing to near-baseline levels during prolonged current pulses that transiently drove the cells at high rates. The current responsible for adaptation was studied in voltage clamp during and after high-frequency driving of the cell and was determined to be a slowly accumulating K+ current. This current was independent of calcium or sodium entry and could be induced with long-duration voltage steps after blockade of action potentials. In addition to the adaptation current, driven firing produced slow inactivation of the persistent Na+ current, which also contributed to the reduced excitability of STN cells during and after driven firing.

scholarly journals Spontaneous Motion on Two-Dimensional Continuous Attractors

2015 ◽  
Vol 27 (3) ◽  
pp. 507-547 ◽  
Author(s):  
C. C. Alan Fung ◽  
S.-i. Amari
Keyword(s):  
Firing Rate ◽  
Synaptic Depression ◽  
Object Motion ◽  
Spike Frequency ◽  
Two Dimensional ◽  
Spike Frequency Adaptation ◽  
Short Term ◽  
Perturbative Approach ◽  
Frequency Adaptation ◽  
Spontaneous Motion

Attractor models are simplified models used to describe the dynamics of firing rate profiles of a pool of neurons. The firing rate profile, or the neuronal activity, is thought to carry information. Continuous attractor neural networks (CANNs) describe the neural processing of continuous information such as object position, object orientation, and direction of object motion. Recently it was found that in one-dimensional CANNs, short-term synaptic depression can destabilize bump-shaped neuronal attractor activity profiles. In this article, we study two-dimensional CANNs with short-term synaptic depression and spike frequency adaptation. We found that the dynamics of CANNs with short-term synaptic depression and CANNs with spike frequency adaptation are qualitatively similar. We also found that in both kinds of CANNs, the perturbative approach can be used to predict phase diagrams, dynamical variables, and speed of spontaneous motion.

scholarly journals Spike Frequency Adaptation and Neocortical Rhythms

2002 ◽  
Vol 88 (2) ◽  
pp. 761-770 ◽  
Author(s):  
Galit Fuhrmann ◽  
Henry Markram ◽  
Misha Tsodyks
Keyword(s):  
Firing Rate ◽  
Pyramidal Neurons ◽  
Spike Frequency ◽  
Spike Frequency Adaptation ◽  
Patch Clamp Technique ◽  
Response Characteristics ◽  
Frequency Adaptation ◽  
Whole Cell Patch Clamp ◽  
The Mean

Spike-frequency adaptation in neocortical pyramidal neurons was examined using the whole cell patch-clamp technique and a phenomenological model of neuronal activity. Noisy current was injected to reproduce the irregular firing typically observed under in vivo conditions. The response was quantified by computing the poststimulus histogram (PSTH). To simulate the spiking activity of a pyramidal neuron, we considered an integrate-and-fire model to which an adaptation current was added. A simplified model for the mean firing rate of an adapting neuron under noisy conditions is also presented. The mean firing rate model provides a good fit to both experimental and simulation PSTHs and may therefore be used to study the response characteristics of adapting neurons to various input currents. The models enable identification of the relevant parameters of adaptation that determine the shape of the PSTH and allow the computation of the response to any change in injected current. The results suggest that spike frequency adaptation determines a preferred frequency of stimulation for which the phase delay of a neuron's activity relative to an oscillatory input is zero. Simulations show that the preferred frequency of single neurons dictates the frequency of emergent population rhythms in large networks of adapting neurons. Adaptation could therefore be one of the crucial factors in setting the frequency of population rhythms in the neocortex.

Encoder Adaptation Modulates the Visual Responses of Crayfish Interneurons

2004 ◽  
Vol 92 (1) ◽  
pp. 327-340 ◽  
Author(s):  
Raymon M. Glantz ◽  
John P. Schroeter
Keyword(s):  
Firing Rate ◽  
Time Course ◽  
Light Flash ◽  
Time Derivative ◽  
Input Resistance ◽  
Spike Frequency ◽  
Visual Response ◽  
Spike Frequency Adaptation ◽  
Visual Responses ◽  
Frequency Adaptation

The responses of sustaining and dimming fibers were characterized by the time varying firing rates elicited by extrinsic current and flashes of light. These data were simulated by an adaptive integrate-and-fire model. A postimpulse shunt conductance simulated spike-frequency adaptation. The correlation between observed and model current-elicited impulse rates was 0.94–0.98. However, except for a difference in input resistance (both measured and simulated), the voltage to impulse encoders of the two cell groups was similar and exhibited comparable degrees of spike-frequency adaptation (40 to 45%). The encoder model derived from current-elicited responses (with fixed parameters) was used to simulate visual responses elicited by light flashes. These simulations included a synaptic current derived from the time course of the postsynaptic potential (PSP). The sustaining fiber visual response consisted of a large excitatory PSP and high-frequency transient burst that adapted (by ∼80%) to a low-frequency plateau discharge. The simulations indicated that spike-frequency adaptation had no effect on the transient discharge but reduced the plateau firing rate by ∼60%. Encoder adaptation enhances the sustaining fiber response to the time derivative of the stimulus. In dimming fibers, the light flash elicits an inhibitory PSP that interrupts the “dark discharge” and an off response following the end of the flash. The simulations indicated that spike-frequency adaptation reduces the firing rate of both the dark discharge and the off response. Thus the model suggests that different effects of encoder adaptation on the two cell types arise from the same encoder mechanisms, but different actions are determined by differences in impulse rate and the time course of the discharge.

Morphological and Electrophysiological Properties of Principal Neurons in the Rat Lateral Amygdala In Vitro

2001 ◽  
Vol 85 (2) ◽  
pp. 714-723 ◽  
Author(s):  
E.S.L. Faber ◽  
R. J. Callister ◽  
P. Sah
Keyword(s):  
Cell Morphology ◽  
Brain Slices ◽  
Spike Trains ◽  
Spike Frequency ◽  
Morphological Properties ◽  
Spike Frequency Adaptation ◽  
Differential Distribution ◽  
Lateral Amygdala ◽  
Frequency Adaptation ◽  
Firing Properties

In this study, we characterize the electrophysiological and morphological properties of spiny principal neurons in the rat lateral amygdala using whole cell recordings in acute brain slices. These neurons exhibited a range of firing properties in response to prolonged current injection. Responses varied from cells that showed full spike frequency adaptation, spiking three to five times, to those that showed no adaptation. The differences in firing patterns were largely explained by the amplitude of the afterhyperpolarization (AHP) that followed spike trains. Cells that showed full spike frequency adaptation had large amplitude slow AHPs, whereas cells that discharged tonically had slow AHPs of much smaller amplitude. During spike trains, all cells showed a similar broadening of their action potentials. Biocytin-filled neurons showed a range of pyramidal-like morphologies, differed in dendritic complexity, had spiny dendrites, and differed in the degree to which they clearly exhibited apical versus basal dendrites. Quantitative analysis revealed no association between cell morphology and firing properties. We conclude that the discharge properties of neurons in the lateral nucleus, in response to somatic current injections, are determined by the differential distribution of ionic conductances rather than through mechanisms that rely on cell morphology.

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