iaf_psc_delta – Current-based leaky integrate-and-fire neuron model with delta-shaped postsynaptic currents =========================================================================================================== Description +++++++++++ ``iaf_psc_delta`` is an implementation of a leaky integrate-and-fire model where the potential jumps on each spike arrival. The threshold crossing is followed by an absolute refractory period during which the membrane potential is clamped to the resting potential. Spikes arriving while the neuron is refractory, are discarded by default. If the property ``refractory_input`` is set to true, such spikes are added to the membrane potential at the end of the refractory period, dampened according to the interval between arrival and end of refractoriness. The linear subthreshold dynamics is integrated by the Exact Integration scheme [1]_. The neuron dynamics is solved on the time grid given by the computation step size. Incoming as well as emitted spikes are forced to that grid. An additional state variable and the corresponding differential equation represents a piecewise constant external current. The general framework for the consistent formulation of systems with neuron like dynamics interacting by point events is described in [1]_. A flow chart can be found in [2]_. Critical tests for the formulation of the neuron model are the comparisons of simulation results for different computation step sizes. sli/testsuite/nest contains a number of such tests. The iaf_psc_delta is the standard model used to check the consistency of the nest simulation kernel because it is at the same time complex enough to exhibit non-trivial dynamics and simple enough compute relevant measures analytically. Parameters ++++++++++ The following parameters can be set in the status dictionary. ================= ======= ====================================================== V_m mV Membrane potential E_L mV Resting membrane potential C_m pF Capacity of the membrane tau_m ms Membrane time constant t_ref ms Duration of refractory period V_th mV Spike threshold V_reset mV Reset potential of the membrane I_e pA Constant input current V_min mV Absolute lower value for the membrane potential refractory_input boolean If true, do not discard input during refractory period. Default: false ================= ======= ====================================================== References ++++++++++ .. [1] Rotter S, Diesmann M (1999). Exact simulation of time-invariant linear systems with applications to neuronal modeling. Biologial Cybernetics 81:381-402. DOI: https://doi.org/10.1007/s004220050570 .. [2] Diesmann M, Gewaltig M-O, Rotter S, & Aertsen A (2001). State space analysis of synchronous spiking in cortical neural networks. Neurocomputing 38-40:565-571. DOI: https://doi.org/10.1016/S0925-2312(01)00409-X Sends +++++ SpikeEvent Receives ++++++++ SpikeEvent, CurrentEvent, DataLoggingRequest See also ++++++++ :doc:`Neuron `, :doc:`Integrate-And-Fire `, :doc:`Current-Based `