Snowden, Thompson and Troscianko: Basic Vision (revised edition)
V1 Simple and Complex Cells
A video from the original experiments by Hubel and Weisel. The video shows the stimuli that the animal is viewing while an electrode is placed near a single cell in area V1. We can hear the firing of the cell.
The first cell is a Simple Cell. Note that it only responds for stimuli at one orientation, and that it responds to light in the centre and darkness (or light being removed) in its surround.
The next cell is a Complex Cell. The first map its receptive field and that show its orientation selectivity. Note that this cell responds to both directions of motion. Note that it responds to BOTH light and dark bars across the receptive field
The next cell is also complex but shows directional selectivity
The final cell is also directionally selective but now also requires that the stimulus is short so that it is confined to the area of the receptive field – these are known as “hypercomplex” cells.