Depressing synapse as a detector of frequency change.

In this article we discuss the short-term synaptic depression using a mathematical model. We derive the model of synaptic depression caused by the depletion of synaptic vesicles for the case of infinitely short stimulation time and show that the analytical formulas for the postsynaptic potential (PSP) and kinetic functions take simple closed form. A solution in this form allows an analysis of the characteristics of depression as a function of the models parameters and the derivation of analytic formulas for measures of short time synaptic depression commonly used in experimental studies. Those formulas are used to validate the model by fitting it to two types of synapses described in the literature. Given the fitted parameters we discuss the behavior of the synapse in situations involving frequency change. We also indicate a possible role of depressing synapses in information processing as not only a filter of high frequency input but as a detector of the return from high frequency stimulation to the stimulation within frequency band specific for a given synapse.

[1]  H. Markram,et al.  Differential signaling via the same axon of neocortical pyramidal neurons. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[2]  S. T. Inouye,et al.  Persistence of circadian rhythmicity in a mammalian hypothalamic "island" containing the suprachiasmatic nucleus. , 1979, Proceedings of the National Academy of Sciences of the United States of America.

[3]  Terrence J. Sejnowski,et al.  An Efficient Method for Computing Synaptic Conductances Based on a Kinetic Model of Receptor Binding , 1994, Neural Computation.

[4]  L. Abbott,et al.  A Quantitative Description of Short-Term Plasticity at Excitatory Synapses in Layer 2/3 of Rat Primary Visual Cortex , 1997, The Journal of Neuroscience.

[5]  A. Thomson.  Activity‐dependent properties of synaptic transmission at two classes of connections made by rat neocortical pyramidal axons in vitro , 1997, The Journal of physiology.

[6]  C. Stevens,et al.  Very short-term plasticity in hippocampal synapses. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[7]  C. Petersen,et al.  Short-term dynamics of synaptic transmission within the excitatory neuronal network of rat layer 4 barrel cortex. , 2002, Journal of neurophysiology.

[8]  J. A. Varela,et al.  Differential Depression at Excitatory and Inhibitory Synapses in Visual Cortex , 1999, The Journal of Neuroscience.

[9]  H. Markram,et al.  Redistribution of synaptic efficacy between neocortical pyramidal neurons , 1996, Nature.

[10]  P. Culicover,et al.  Neural connections, mental computation , 1988 .

[11]  L. Dobrunz,et al.  Mechanisms of target‐cell specific short‐term plasticity at Schaffer collateral synapses onto interneurones versus pyramidal cells in juvenile rats , 2005, The Journal of physiology.

[12]  L. Abbott,et al.  Synaptic Depression and Cortical Gain Control , 1997, Science.

[13]  S. Ozawa,et al.  Glial Glutamate Transporters Maintain One-to-One Relationship at the Climbing Fiber–Purkinje Cell Synapse by Preventing Glutamate Spillover , 2006, The Journal of Neuroscience.

[14]  Terrence J. Sejnowski,et al.  Synthesis of models for excitable membranes, synaptic transmission and neuromodulation using a common kinetic formalism , 1994, Journal of Computational Neuroscience.

[15]  C. Allen,et al.  GABAergic synapses of the suprachiasmatic nucleus exhibit a diurnal rhythm of short‐term synaptic plasticity , 2004, The European journal of neuroscience.

[16]  C. Stevens,et al.  Facilitation and depression at single central synapses , 1995, Neuron.

[17]  Alex M Thomson,et al.  Layer 6 cortico-thalamic pyramidal cells preferentially innervate interneurons and generate facilitating EPSPs. , 2006, Cerebral cortex.

[18]  Mark J. Wall,et al.  Short‐term synaptic plasticity during development of rat mossy fibre to granule cell synapses , 2005, The European journal of neuroscience.

[19]  J. Żygierewicz,et al.  Short term synaptic depression model--analytical solution and analysis. , 2008, Journal of theoretical biology.

[20]  Alex M Thomson,et al.  Dynamic properties of excitatory synaptic connections involving layer 4 pyramidal cells in adult rat and cat neocortex. , 2007, Cerebral cortex.

[21]  B. Connors,et al.  Sensory experience modifies the short-term dynamics of neocortical synapses , 1999, Nature.

[22]  F. Benfenati,et al.  Lack of Synapsin I Reduces the Readily Releasable Pool of Synaptic Vesicles at Central Inhibitory Synapses , 2007, The Journal of Neuroscience.

[23]  H. Markram,et al.  The neural code between neocortical pyramidal neurons depends on neurotransmitter release probability. , 1997, Proceedings of the National Academy of Sciences of the United States of America.