Figure 14.8. Lateral view of brain showing locations of several visual areas in
the posterior cortex.
Much of what has been learned about the structure and function of
these regions of the brain has been accomplished by measuring neural
signals in the cortex of various animals during the presentation of
specific kinds of visual stimuli. David Hubel (1926-2013) and Torsten
Wiesel (b. 1924) were pioneers in conducting these kinds of measure-
ments; they were experimental collaborators for 25 years.
Information about which brain areas are doing what vis-a-vis vision
also comes from the study of people who have suffered brain lesions
(usually from strokes) that are found to be associated with specific
deficits in visual perception. And, more recently, functional brain
imaging has allowed the mapping of properties of the human visual
cortex in healthy, living humans (see Chapter 17). A lesion in V1 re-
sults in a visual scotoma (Latin skotos = dark), a blind spot in a specific
region of space. Because the axons from LGN cells into the visual