CHAPTER 4: The Visual Cortex and Beyond

Question 1

What is the pathway to the brain featured in Chapter 4

Answer 1

Visual signals leave the back of the brain through the optic nerve and meet at the optic chasim (an X shape). Anything to the right of the visual point is processed by the left hemisphere of the brain and visa-versa (they cross over to the other side after meeting in the optic chasim). 90% of the signals head to the LGN, and 10% of the signals go to the superior colliculus, which is involved in eye movements. Then the visual signals move to the occipital lobe, the visual recieving area (striate cortex).

Question 2

How is the receptive field of neurons in the visual cortex different from that of ganglion cells?

Answer 2

Receptive fields: Ganglion cells are arranged more simply, in a center-surround structure. Whereas, visual cortex neurons have much more complex receptive fields.
Field Size: ganglion cells have smaller receptive fields in the fovea and allows for high spatial resolution, but low field coverage. Receptive fields of cortical neurons are larger making them better for detecting patterns and movements over larger distances
Adaptibility: ganglion cells do not adapt well, but neurons in the visual cortex adapt by learning and experience.

Question 3

What is the role of feature detectors in perception?

Answer 3

Feature detectors help to respond to specific features of a stimulus in the environment by detecting different aspects of different stimuli (shapes, lines, angles, movements), recognizing different patterns, and processing higher level vs. lower level stimulus

Question 4

What is selective adaptation?

Answer 4

A procedure of which a person or animal is selectively exposed to one stimulus -> generally, the sensitivity to the exposed stimulus is decreased ->

Question 5

Dorsal vs ventral pathway

Answer 5

Dorsal pathway: conducts signals from the visual recieving area (striate area) to the parital lobe to help process objects spatial location relative to the viewer (where, how, action pathway)
Ventral pathway: conducts signals from the visual recieving area (straite area) to the temporal lobe to help recognize objects (what pathway)