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GaborDS.0.1

2007 Feb 10
Summary   This is a direction selective (DS) spiking unit. It consists of a space-time oriented Gabor filter and a conductance-driven integrate-and-fire spike generator. This simple model captures some of the tuning properties of a typical macaque V1 simple DS cell.

GaborDS.0.1.mod

Data

Results

The results here were obtained using this response file, which records spikes from a DS unit near the center of the stimulus grid.

Sine Tuning

• Direction - at TF 10 Hz, SF 1.2 cyc/deg
• Spatial frequency - in preferred and anti-preferred direction
• Temporal frequency - at SF 1.2 cyc/deg
• Static phase

Dynamic Random Stimuli

• Random direction vs. TF
• Random direction vs. starting phase for slow TF - The ETF is 1.6 Hz, so the random walk only explores a limited region around the start phase.

Discussion

The STAs for the random direction stimulus show no systematic change in shape with speed (equivalent TFs). This is at odds with experimental results for DS simple and complex cells in V1, which tend to have wider STAs for slower motion.

When STAs are computed at a slow speed for which the random walk of the grating explores only a limited fraction of the circle, then the shape of the STAs seems to vary somewhat with the starting spatial phase, although the amount of variation observed in the Results above for ETF 1.6 Hz is small relative to the width of the STAs