MT spike generation

The <spike_gen> object specifies how the time-varying integrated response of each MT unit is transformed to generate action potentials. Basically, the raw MT response is shifted and scaled and then half-wave rectified and interpreted as a spiking probability.

  <spike_gen>
    type        poisson     # Spike gen. algorithm, dflt "poisson"; "ifc"
    offset0     0.0         # Add to filter output, BEFORE scaling (0.0)
    scale       0.004       # Multiply filter output (1.0)
    offset      0.001       # Add to filter output, AFTER scaling (0.0)
    toffset     0.060   (s) # Time delay added to spike times
    spike_dump  0           # Dump firing probability to 'zz.dump.pl' if 1
  </spike_gen>

The type parameter here specifies poisson, indicating that spikes will be generated using a pseudorandom Poisson spike generator.

The order of operations is:

1. offset0 is added to the raw signal.
2. The signal is now scaled by scale.
3. offset is now added to the signal.
4. A temporal offset toffset is applied to the signal.
5. The signal is half-wave rectified.
6. The signal is interpreted as a firing probability per millisecond.
7. Poisson spikes are generated.