Torsten Weisel

David Hubel

Major discoveries• Cell types in V1• Functional organization of V1 (Maps and

columns)

Direction selective cells

Response Properties of V1 Neurons Simple cells: 1. Low spontaneous activity (quiet when not stimulated). 2. Receptive fields are elongated (not circular) and are also divided into excitatory (+) and inhibitory (-) regions. 3. The (+) and (-) regions do not form a center and a surround but form alternating stripes (rectangular regions) -- edge detectors, slit detectors, line detectors. 4. They are position (or phase) selective. 5. They are orientation selective. 6. They are size selective. 7. They are often direction selective. 8. They are often disparity selective.

Response Properties of V1 Neurons Complex cells: 1. Low spontaneous activity (quiet when not stimulated). 2. Receptive fields are elongated (not circular). 3. Do not form a center and a surround rather they behave like edge detectors, slit detectors, or line detectors. 4. They are not selective to position (or phase). 5. They are orientation selective. 6. They are size selective. 7. They are often direction selective. 8. They are often disparity selective.

Monocular left eye

Monocular right eye

Equal dominance{{Dominated by left eye

Dominated by right eye

Fitzpatrick

Cytochrome oxidase blobs

(at locations of cytochrome oxidase blobs)