iaf_psc_delta_ps.h

Go to the documentation of this file.

/*
 *  iaf_psc_delta_ps.h
 *
 *  This file is part of NEST.
 *
 *  Copyright (C) 2004 The NEST Initiative
 *
 *  NEST is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  NEST is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with NEST.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
 
#ifndef IAF_PSC_DELTA_PS_H
#define IAF_PSC_DELTA_PS_H
 
// Generated includes:
#include "config.h"
 
// Includes from nestkernel:
#include "archiving_node.h"
#include "connection.h"
#include "event.h"
#include "nest_types.h"
#include "ring_buffer.h"
#include "slice_ring_buffer.h"
#include "universal_data_logger.h"
 
namespace nest
{
 
/* BeginUserDocs: neuron, integrate-and-fire, current-based, precise, hard threshold
 
Short description
+++++++++++++++++
 
Current-based leaky integrate-and-fire neuron model with delta-shaped
postsynaptic currents - precise spike timing version
 
Description
+++++++++++
 
``iaf_psc_delta_ps`` 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 :footcite:p:`Rotter1999`. The neuron dynamics are solved exactly in
time. Incoming and outgoing spike times are handled precisely :footcite:p:`Morrison2007a`.
 
An additional state variable and the corresponding differential
equation represents a piecewise constant external current.
 
Spikes can occur either on receipt of an excitatory input spike, or
be caused by a depolarizing input current.  Spikes evoked by
incoming spikes, will occur precisely at the time of spike arrival,
since incoming spikes are modeled as instantaneous potential
jumps. Times of spikes caused by current input are determined
exactly by solving the membrane potential equation. Note that, in
contrast to the neuron models discussed in :footcite:p:`Morrison2007a` :footcite:p:`Hanuschkin2010`, this model has so
simple dynamics that no interpolation or iterative spike location
technique is required at all.
 
The general framework for the consistent formulation of systems with
neuron like dynamics interacting by point events is described in
:footcite:p:`Rotter1999`. A flow chart can be found in :footcite:p:`Diesmann2001`.
 
Critical tests for the formulation of the neuron model are the
comparisons of simulation results for different computation step
sizes and the testsuite contains a number of such tests.
 
The ``iaf_psc_delta_ps`` 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.
 
Please note that this node is capable of sending precise spike times
to target nodes (on-grid spike time plus offset).
 
The ``af_psc_delta_ps`` neuron accepts connections transmitting
``CurrentEvents``. These events transmit stepwise-constant currents which
can only change at on-grid times.
 
For details about exact subthreshold integration, please see
:doc:`../neurons/exact-integration`.
 
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      Capacitance of the membrane
 tau_m             ms      Membrane time constant
 t_ref             ms      Duration of refractory period
 V_th              ms      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  (bool)  If true, keep input during refractory period (default: false)
=================  ======  ==============================================================
 
References
++++++++++
 
.. footbibliography::
 
Sends
+++++
 
SpikeEvent
 
Receives
++++++++
 
SpikeEvent, CurrentEvent, DataLoggingRequest
 
See also
++++++++
 
iaf_psc_delta, iaf_psc_exp_ps
 
Examples using this model
+++++++++++++++++++++++++
 
.. listexamples:: iaf_psc_delta_ps
 
EndUserDocs */
 
void register_iaf_psc_delta_ps( const std::string& name );
 
class iaf_psc_delta_ps : public ArchivingNode
{
 
public:
  iaf_psc_delta_ps();
 
  iaf_psc_delta_ps( const iaf_psc_delta_ps& );
 
  using Node::handle;
  using Node::handles_test_event;
 
  size_t send_test_event( Node&, size_t, synindex, bool ) override;
 
  size_t handles_test_event( SpikeEvent&, size_t ) override;
  size_t handles_test_event( CurrentEvent&, size_t ) override;
  size_t handles_test_event( DataLoggingRequest&, size_t ) override;
 
  void handle( SpikeEvent& ) override;
  void handle( CurrentEvent& ) override;
  void handle( DataLoggingRequest& ) override;
 
  bool
  is_off_grid() const override
  {
    return true;
  }  // uses off_grid events
 
  void get_status( Dictionary& ) const override;
  void set_status( const Dictionary& ) override;
 
private:
  void init_buffers_() override;
 
  void pre_run_hook() override;
  void update( Time const&, const long, const long ) override;
 
  void emit_spike_( Time const& origin, const long lag, const double offset_U );
 
  void emit_instant_spike_( Time const& origin, const long lag, const double spike_offset );
 
  void propagate_( const double dt );
 
  // ----------------------------------------------------------------
 
  struct Parameters_
  {
 
    double tau_m_;
 
    double c_m_;
 
    double t_ref_;
 
    double E_L_;
 
    double I_e_;
 
    double U_th_;
 
    double U_min_;
 
    double U_reset_;
 
    Parameters_();  
 
    void get( Dictionary& ) const;  
 
    double set( const Dictionary&, Node* );
  };
 
 
  // The next two classes need to be friends to access the State_ class/member
  friend class RecordablesMap< iaf_psc_delta_ps >;
  friend class UniversalDataLogger< iaf_psc_delta_ps >;
 
  // ----------------------------------------------------------------
 
  struct State_
  {
    double U_;
    double I_;  
 
    long last_spike_step_;
    double last_spike_offset_;  
 
    bool is_refractory_;    
    bool with_refr_input_;  
 
    State_();  
 
    void get( Dictionary&, const Parameters_& ) const;
 
    void set( const Dictionary&, const Parameters_&, double, Node* );
  };
 
  // ----------------------------------------------------------------
 
  struct Buffers_
  {
    Buffers_( iaf_psc_delta_ps& );
    Buffers_( const Buffers_&, iaf_psc_delta_ps& );
 
    SliceRingBuffer events_;
 
    RingBuffer currents_;
 
    UniversalDataLogger< iaf_psc_delta_ps > logger_;
  };
 
  // ----------------------------------------------------------------
 
  struct Variables_
  {
    double exp_t_;    
    double expm1_t_;  
    double R_;        
 
    double h_ms_;  
 
    long refractory_steps_;  
 
    double refr_spikes_buffer_;
  };
 
  // Access functions for UniversalDataLogger -------------------------------
 
  double
  get_V_m_() const
  {
    return S_.U_ + P_.E_L_;
  }
 
  // ----------------------------------------------------------------
 
  Parameters_ P_;
  State_ S_;
  Variables_ V_;
  Buffers_ B_;
  static RecordablesMap< iaf_psc_delta_ps > recordablesMap_;
};
 
 
inline size_t
iaf_psc_delta_ps::send_test_event( Node& target, size_t receptor_type, synindex, bool )
{
  SpikeEvent e;
  e.set_sender( *this );
  return target.handles_test_event( e, receptor_type );
}
 
inline size_t
iaf_psc_delta_ps::handles_test_event( SpikeEvent&, size_t receptor_type )
{
  if ( receptor_type != 0 )
  {
    throw UnknownReceptorType( receptor_type, get_name() );
  }
  return 0;
}
 
inline size_t
iaf_psc_delta_ps::handles_test_event( CurrentEvent&, size_t receptor_type )
{
  if ( receptor_type != 0 )
  {
    throw UnknownReceptorType( receptor_type, get_name() );
  }
  return 0;
}
 
inline size_t
iaf_psc_delta_ps::handles_test_event( DataLoggingRequest& dlr, size_t receptor_type )
{
  if ( receptor_type != 0 )
  {
    throw UnknownReceptorType( receptor_type, get_name() );
  }
  return B_.logger_.connect_logging_device( dlr, recordablesMap_ );
}
 
inline void
iaf_psc_delta_ps::get_status( Dictionary& d ) const
{
  P_.get( d );
  S_.get( d, P_ );
  ArchivingNode::get_status( d );
 
  d[ names::recordables ] = recordablesMap_.get_list();
}
 
inline void
iaf_psc_delta_ps::set_status( const Dictionary& d )
{
  Parameters_ ptmp = P_;                        // temporary copy in case of errors
  const double delta_EL = ptmp.set( d, this );  // throws if BadProperty
  State_ stmp = S_;                             // temporary copy in case of errors
  stmp.set( d, ptmp, delta_EL, this );          // throws if BadProperty
 
  // We now know that (ptmp, stmp) are consistent. We do not
  // write them back to (P_, S_) before we are also sure that
  // the properties to be set in the parent class are internally
  // consistent.
  ArchivingNode::set_status( d );
 
  // if we get here, temporaries contain consistent set of properties
  P_ = ptmp;
  S_ = stmp;
}
 
}  // namespace
 
#endif  // IAF_PSC_DELTA_PS_H