The Neural Control of Vision
H. The Function of the Midget and Parasol Channels in Vision

The nature of the connections of the midget and parasol cells to the cortex has been extensively debated. It had initially been thought that these two classes remain separate until they reach extrastriate cortex and there specifically target selected areas. To test this several laboratories have introduced the method depicted in Figure 29. Small regions of the parvocellular or magnocellular layers of the LGN, through which the midget and parasol cells project to cortex, are inactivated by various substances while recording in areas V1, V4, and MT.