scholarly journals Predicting the response of striatal spiny neurons to sinusoidal input

2017 ◽  
Vol 118 (2) ◽  
pp. 855-873 ◽  
Author(s):  
Charles. J. Wilson
Keyword(s):  
Firing Rate ◽  
Action Potentials ◽  
Interspike Interval ◽  
Spike Timing ◽  
Repetitive Firing ◽  
Phase Resetting ◽  
Spiny Neurons ◽  
Wide Range ◽  
Sinusoidal Input ◽  
Sinusoidal Currents

During repetitive firing, the timing of action potentials is determined by the interaction between the input and voltage-sensitive currents throughout the interspike interval. This interaction is encapsulated in the neuron’s phase-resetting curve. The phase-resetting curve predicted spike timing to small sinusoidal currents over a wide range of stimulus frequencies. Firing patterns were most sensitive to oscillatory components near the cell’s own firing rate, even in the presence of noise and other inputs.

Repetitive firing in layer V neurons from cat neocortex in vitro

1984 ◽  
Vol 52 (2) ◽  
pp. 264-277 ◽  
Author(s):  
C. E. Stafstrom ◽  
P. C. Schwindt ◽  
W. E. Crill
Keyword(s):  
Firing Rate ◽  
Interspike Interval ◽  
Rate Of Change ◽  
Repetitive Firing ◽  
Linear Segment ◽  
Interspike Intervals ◽  
Firing Rates ◽  
Wide Range ◽  
Layer V

Input-output relations of large neurons from layer V of cat sensorimotor cortex were studied in an in vitro slice preparation using steps and ramps of intracellularly injected current. Depolarization attained during the interspike interval (ISI) was compared to the voltage levels required to activate a previously described (29) persistent sodium current (INaP). INaP was studied using a single-electrode voltage clamp in the same cells tested for firing behavior. Following an injected current step, firing rate declined smoothly to a steady level with a time course that was approximately exponential in most cells (tau, 9-43 ms). In most cells, the relation between firing rate and injected current (f-I relation) consisted of two linear segments, both for adapted, steady firing and for early intervals during adaptation. The slope of the steeper, initial (or sole) linear segment of the f-I curve averaged 26.2 Hz/nA during steady firing and was steeper when plotted for early interspike intervals. The variation of the depolarization at which spike initiation occurred (firing level) and the membrane potential between rhythmic spikes was examined during adaptation and steady firing. In most cells, firing level rose rapidly during a rhythmic train to a steady value. The steady firing level attained remained unchanged over a wide range of steady firing rates. Nevertheless, the mean depolarization during the interspike interval (V) increased approximately linearly with steady firing rate. Even at the slowest firing rates, V is sufficient to activate INaP. The use of injected current ramps demonstrated that neocortical cells were sensitive to rate of change of stimulus current (dI/dt) as well as its amplitude (I). The use of ramps followed by steady currents demonstrated that the repetitive response lagged behind changes in stimulus parameters and did not reach a steady state even during slow ramps; i.e., the response depended on time as well as on I and dI/dt. Instantaneous firing rate during the ramp increased linearly with time for a wide range of ramp slopes (dI/dt). The instantaneous firing rate of early interspike intervals was also linearly related to ramp slope for small ramp slopes. In spite of these linear relationships, quantitative analysis indicated that firing rate during ramp stimulation cannot, in general, be described by a simple linear combination of separate amplitude- and rate-dependent terms. The repetitive firing properties of the in vitro neurons are compared to those of in vivo neocortical neurons and other cell types.(ABSTRACT TRUNCATED AT 400 WORDS)

Voltage-clamp analysis and computational model of dopaminergic neurons from mouse retina

2004 ◽  
Vol 21 (6) ◽  
pp. 835-849 ◽  
Author(s):  
JIANGUO XIAO ◽  
YIDAO CAI ◽  
JASPER YEN ◽  
MICHAEL STEFFEN ◽  
DOUGLAS A. BAXTER ◽  
...  
Keyword(s):  
Computational Model ◽  
Firing Rate ◽  
Voltage Clamp ◽  
Action Potentials ◽  
Membrane Potentials ◽  
Mouse Retina ◽  
Delayed Rectifier ◽  
Wide Range ◽  
Spontaneous Action ◽  
Spontaneous Action Potentials

Isolated dopaminergic amacrine (DA) cells in mouse retina fire rhythmic, spontaneous action potentials and respond to depolarizing current with trains of low-frequency action potentials. To investigate the roles of voltage-gated ion channels in these processes, the transient A-type K+ current (IK,A) and Ca2+ current (ICa) in isolated mouse DA cells were analyzed by voltage clamp. The IK,A activated at −60 mV and inactivated rapidly. ICa activated at around −30 mV and reached a peak at 10 mV without apparent inactivation. We also extended our previous computational model of the mouse DA cell to include the new electrophysiological data. The model consisted of a membrane capacitance in parallel with eight currents: Na+ transient (INa,T), Na+ persistent (INa,P), delayed rectifier potassium (IKdr), IK,A, calcium-dependent potassium (IK,Ca), L-type Ca2+ ICa, hyperpolarization-activated cation current (Ih), and a leak current (IL). Hodgkin-Huxley type equations were used to define the voltage- and time-dependent activation and inactivation. The simulations were implemented using the neurosimulator SNNAP. The model DA cell was spontaneously active from a wide range of initial membrane potentials. The spontaneous action potentials reached 35 mV at the peak and hyperpolarized to −76 mV between spikes. The spontaneous firing frequency in the model was 6 Hz. The model DA cell responded to prolonged depolarizing current injection by increasing its spiking frequency and eventually reaching a depolarization block at membrane potentials greater than −10 mV. The most important current for determining the firing rate was IK,A. When the amplitude of IK,A was decreased, the firing rate increased. ICa and IK,Ca also affected the width of action potentials but had only minor effects on the firing rate. Ih affected the firing rate slightly but did not change the waveform of the action potentials.

Conductance-Based Integrate-and-Fire Models

1997 ◽  
Vol 9 (3) ◽  
pp. 503-514 ◽  
Author(s):  
Alain Destexhe
Keyword(s):  
High Frequency ◽  
Action Potentials ◽  
Time Course ◽  
Quantitative Model ◽  
Spike Timing ◽  
Repetitive Firing ◽  
Network Behavior ◽  
Neuronal Responses ◽  
Potential Generation ◽  
Integrate And Fire

A conductance-based model of Na+ and K+ currents underlying action potential generation is introduced by simplifying the quantitative model of Hodgkin and Huxley (HH). If the time course of rate constants can be approximated by a pulse, HH equations can be solved analytically. Pulse-based (PB) models generate action potentials very similar to the HH model but are computationally faster. Unlike the classical integrate-and fire (IAF) approach, they take into account the changes of conductances during and after the spike, which have a determinant influence in shaping neuronal responses. Similarities and differences among PB, IAF, and HH models are illustrated for three cases: high-frequency repetitive firing, spike timing following random synaptic inputs, and network behavior in the presence of intrinsic currents.

scholarly journals Modulation of motoneuron firing by recurrent inhibition in the adult rat in vivo

2014 ◽  
Vol 112 (9) ◽  
pp. 2302-2315 ◽  
Author(s):  
Ahmed Z. Obeidat ◽  
Paul Nardelli ◽  
Randall K. Powers ◽  
Timothy C. Cope
Keyword(s):  
Firing Rate ◽  
Neural Circuit ◽  
Average Rate ◽  
Spike Timing ◽  
Recurrent Inhibition ◽  
Repetitive Firing ◽  
Synaptic Inhibition ◽  
Adult Rat ◽  
Electrophysiological Studies

Recent reports show that synaptic inhibition can modulate postsynaptic spike timing without having strong effects on firing rate. Thus synaptic inhibition can achieve multiplicity in neural circuit operation through variable modulation of postsynaptic firing rate vs. timing. We tested this possibility for recurrent inhibition (RI) of spinal motoneurons. In in vivo electrophysiological studies of adult Wistar rats anesthetized by isoflurane, we examined repetitive firing of individual lumbosacral motoneurons recorded in current clamp and modulated by synchronous antidromic electrical stimulation of multiple motor axons and their centrally projecting collateral branches. Antidromic stimulation produced recurrent inhibitory postsynaptic potentials (RIPSPs) having properties similar to those detailed in the cat. Although synchronous RI produced marked short-term modulation of motoneuron spike timing and instantaneous firing rate, there was little or no suppression of average firing rate. The bias in firing modulation of timing over average rate was observed even for high-frequency RI stimulation (100 Hz), perhaps because of the brevity of RIPSPs, which were more than twofold shorter during motoneuron firing compared with rest. These findings demonstrate that RI in the mammalian spinal cord has the capacity to support and not impede heightened motor pool activity, possibly during rapid, forceful movements.

scholarly journals A Reinforcement Learning Framework for Spiking Networks with Dynamic Synapses

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Karim El-Laithy ◽  
Martin Bogdan
Keyword(s):  
Reinforcement Learning ◽  
Spike Timing ◽  
Neural Representation ◽  
Model Parameters ◽  
Learning Framework ◽  
Reference Target ◽  
Wide Range ◽  
Spiking Network ◽  
Dynamic Synapses ◽  
Exclusive Or

An integration of both the Hebbian-based and reinforcement learning (RL) rules is presented for dynamic synapses. The proposed framework permits the Hebbian rule to update the hidden synaptic model parameters regulating the synaptic response rather than the synaptic weights. This is performed using both the value and the sign of the temporal difference in the reward signal after each trial. Applying this framework, a spiking network with spike-timing-dependent synapses is tested to learn the exclusive-OR computation on a temporally coded basis. Reward values are calculated with the distance between the output spike train of the network and a reference target one. Results show that the network is able to capture the required dynamics and that the proposed framework can reveal indeed an integrated version of Hebbian and RL. The proposed framework is tractable and less computationally expensive. The framework is applicable to a wide class of synaptic models and is not restricted to the used neural representation. This generality, along with the reported results, supports adopting the introduced approach to benefit from the biologically plausible synaptic models in a wide range of intuitive signal processing.

scholarly journals Effects of memristive synapse radiation interactions on learning in spiking neural networks

2021 ◽  
Vol 3 (5) ◽  
Author(s):  
Sumedha Gandharava Dahl ◽  
Robert C. Ivans ◽  
Kurtis D. Cantley
Keyword(s):  
Action Potentials ◽  
Radiation Effects ◽  
Synaptic Weight ◽  
Learning Rule ◽  
Spike Timing ◽  
Spiking Neural Network ◽  
Synaptic Action ◽  
Drift Model ◽  
Spatio Temporal ◽  
Post Synaptic Neuron

AbstractThis study uses advanced modeling and simulation to explore the effects of external events such as radiation interactions on the synaptic devices in an electronic spiking neural network. Specifically, the networks are trained using the spike-timing-dependent plasticity (STDP) learning rule to recognize spatio-temporal patterns (STPs) representing 25 and 100-pixel characters. Memristive synapses based on a TiO2 non-linear drift model designed in Verilog-A are utilized, with STDP learning behavior achieved through bi-phasic pre- and post-synaptic action potentials. The models are modified to include experimentally observed state-altering and ionizing radiation effects on the device. It is found that radiation interactions tend to make the connection between afferents stronger by increasing the conductance of synapses overall, subsequently distorting the STDP learning curve. In the absence of consistent STPs, these effects accumulate over time and make the synaptic weight evolutions unstable. With STPs at lower flux intensities, the network can recover and relearn with constant training. However, higher flux can overwhelm the leaky integrate-and-fire post-synaptic neuron circuits and reduce stability of the network.

Spike-Timing-Dependent Hebbian Plasticity as Temporal Difference Learning

2001 ◽  
Vol 13 (10) ◽  
pp. 2221-2237 ◽  
Author(s):  
Rajesh P. N. Rao ◽  
Terrence J. Sejnowski
Keyword(s):  
Cortical Neuron ◽  
Action Potentials ◽  
Learning Rule ◽  
Spike Timing ◽  
Biophysical Model ◽  
Excitatory Synapses ◽  
Temporal Difference ◽  
Temporal Difference Learning ◽  
Neocortical Neurons ◽  
Hebbian Plasticity

A spike-timing-dependent Hebbian mechanism governs the plasticity of recurrent excitatory synapses in the neocortex: synapses that are activated a few milliseconds before a postsynaptic spike are potentiated, while those that are activated a few milliseconds after are depressed. We show that such a mechanism can implement a form of temporal difference learning for prediction of input sequences. Using a biophysical model of a cortical neuron, we show that a temporal difference rule used in conjunction with dendritic backpropagating action potentials reproduces the temporally asymmetric window of Hebbian plasticity observed physiologically. Furthermore, the size and shape of the window vary with the distance of the synapse from the soma. Using a simple example, we show how a spike-timing-based temporal difference learning rule can allow a network of neocortical neurons to predict an input a few milliseconds before the input's expected arrival.

Phase resetting of spontaneously beating embryonic ventricular heart cell aggregates

1986 ◽  
Vol 251 (6) ◽  
pp. H1298-H1305 ◽  
Author(s):  
M. R. Guevara ◽  
A. Shrier ◽  
L. Glass
Keyword(s):  
Action Potentials ◽  
High Amplitude ◽  
Heart Cell ◽  
Cell Aggregates ◽  
Embryonic Chick ◽  
Phase Resetting ◽  
Stimulus Amplitude ◽  
High Stimulus ◽  
Very High ◽  
Spontaneous Rhythm

The influence of isolated 20-ms duration current pulses on the spontaneous rhythm of embryonic chick ventricular heart cell aggregates was studied. A pulse could either delay or advance the time of occurrence of the next action potential, depending on whether it fell early or late in the cycle. As the stimulus amplitude was increased, the transition from delay to advance occurred over a narrower range of coupling intervals. At low-stimulus amplitudes the transition from delay to advance occurred in a smooth continuous fashion; at medium-stimulus amplitudes the transition was discontinuous; at high-stimulus amplitudes graded action potentials were seen. It was impossible to annihilate spontaneous activity in aggregates with a single stimulus. The phase-resetting response to hyperpolarizing pulses was qualitatively the reverse of that produced by depolarizing pulses. A very high-amplitude depolarizing or hyperpolarizing pulse could produce rapid repetitive activity. Theoretical aspects of these phenomena are discussed.

Electrophysiological and Morphological Changes in Striatal Spiny Neurons in R6/2 Huntington's Disease Transgenic Mice

2001 ◽  
Vol 86 (6) ◽  
pp. 2667-2677 ◽  
Author(s):  
Gloria J. Klapstein ◽  
Robin S. Fisher ◽  
Hadi Zanjani ◽  
Carlos Cepeda ◽  
Eve S. Jokel ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Action Potentials ◽  
Morphological Changes ◽  
Brain Slices ◽  
Cag Repeats ◽  
Membrane Properties ◽  
Striatal Neurons ◽  
Spiny Neurons ◽  
Active Membrane

We examined passive and active membrane properties and synaptic responses of medium-sized spiny striatal neurons in brain slices from presymptomatic (∼40 days of age) and symptomatic (∼90 days of age) R6/2 transgenics, a mouse model of Huntington's disease (HD) and their age-matched wild-type (WT) controls. This transgenic expresses exon 1 of the human HD gene with ∼150 CAG repeats and displays a progressive behavioral phenotype associated with numerous neuronal alterations. Intracellular recordings were obtained using standard techniques from R6/2 and age-matched WT mice. Few electrophysiological changes occurred in striatal neurons from presymptomatic R6/2 mice. The changes in this age group were increased neuronal input resistance and lower stimulus intensity to evoke action potentials (rheobase). Symptomatic R6/2 mice exhibited numerous electrophysiological alterations, including depolarized resting membrane potentials, increased input resistances, decreased membrane time constants, and alterations in action potentials. Increased stimulus intensities were required to evoke excitatory postsynaptic potentials (EPSPs) in neurons from symptomatic R6/2 transgenics. These EPSPs had slower rise times and did not decay back to baseline by 45 ms, suggesting a more prominent component mediated by activation of N-methyl-d-aspartate receptors. Neurons from both pre- and symptomatic R6/2 mice exhibited reduced paired-pulse facilitation. Data from biocytin-filled or Golgi-impregnated neurons demonstrated decreased dendritic spine densities, smaller diameters of dendritic shafts, and smaller dendritic fields in symptomatic R6/2 mice. Taken together, these findings indicate that passive and active membrane and synaptic properties of medium-sized spiny neurons are altered in the R6/2 transgenic. These physiological and morphological alterations will affect communication in the basal ganglia circuitry. Furthermore, they suggest areas to target for pharmacotherapies to alleviate and reduce the symptoms of HD.

Serotonin has different effects on two classes of Betz cells from the cat

1994 ◽  
Vol 72 (4) ◽  
pp. 1925-1937 ◽  
Author(s):  
W. J. Spain
Keyword(s):  
Firing Rate ◽  
Potassium Conductance ◽  
Membrane Conductance ◽  
Constant Current ◽  
Repetitive Firing ◽  
Calcium Dependent ◽  
Constant Current Stimulation ◽  
Ionic Mechanisms ◽  
Betz Cells

1. Intracellular recording from cat Betz cells in vitro revealed a strong correlation between the dominant effect of serotonin (5-HT) and the Betz cell subtype in which it occurred. In large Betz cells that show posthyperpolarization excitation (termed PHE cells), 5-HT evoked a long-lasting membrane depolarization, whereas 5-HT evoked an initial hyperpolarization of variable duration in smaller Betz cells that show posthyperpolorization inhibition (termed PHI cells). 2. Voltage-clamp studies revealed that 5-HT caused a depolarizing shift of activation of the cation current Ih, which resulted in the depolarization in PHE cells, whereas the hyperpolarization in PHI cells is caused by an increase in a resting potassium conductance. 3. The effect of 5-HT on firing properties during constant current stimulation also differed consistently in the two types of Betz cells. In PHE cells the initial firing rate increased after 5-HT application, but the steady firing was unaffected. The depolarizing shift of Ih activation caused the increase of initial firing rate. 4. In PHI cells 5-HT caused a decrease in spike frequency adaptation. The decrease in adaptation was caused by a combination of two conductance changes. First, 5-HT caused a slow afterdepolarization in PHI cells that could trigger repetitive firing in the absence of further stimulation. The sADP depended on calcium entry through voltage-gated channels and was associated with a decrease in membrane conductance. Second, 5-HT caused reduction of a slow calcium-dependent potassium current that normally contributes to slow adaptation. 5. In conclusion, the effect of 5-HT on excitability differs systematically in Betz cell subtypes in part because they have different dominant ionic mechanisms that are modulated. If we assume that PHE cells and PHI cells represent fast and slow pyramidal tract (PT) neurons respectively, 5-HT will cause early recruitment of fast PT cells and delay recruitment of slow PT cells during low levels of synaptic excitation.

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