6.3 Parallel Processing In The Visual Cortex Flashcards
It is natural to assume that anyone who sees something sees ____ about it – its shape, colour, location, and movement. Ordinarily, a person as a whole does see all these aspects, but each individual area of the visual cortex does not.
everything
Different parts of the brains visual system get information on a ____ basis. Eg. Cells that are helping your hand muscles reach out to an object need to know the size and location of the object, but they don’t need to know about colour.
need-to-know
The principal behind vision is ____: when you see something, one part of your brain sees its shape, another sees colour, another detects location, and another perceives movement.
counterintuitive
The primary visual cortex (V1) send information to the ____ ____ ____ (area V2), which processes the information further and transmits it to additional areas.
secondary visual cortex
The connections in the visual cortex are ____. For example, V1 sends information to V2, and V2 returns information to V1. From V2, the information brunches out in several directions for specialised processing.
reciprocal
One important distinction in vision is between the ____ stream and the ____ stream.
ventral : dorsal
The ____ ____ through the temporal cortex is called the “what” pathway, because it is specialised for identifying and recognising objects.
ventral stream
The ____ ____ through the parietal cortex is the “where” pathway, because it helps the motor system locate objects.
dorsal stream
The two streams, the ventral and dorsal, ____, and each participates to some extent in perceiving both shape and location.
communicate
People with damage to the dorsal stream (parietal cortex) seem in most ways to have normal vision. They can read, recognise faces, and describe objects in detail. But although they know “what” things are, they don’t know “____” they are. They can’t accurately reach out to grasp an object.
where
People with damage to the ventral stream (the temple cortex) see “where” are but not “____”. They can see where objects are, even though they have trouble identifying what they are.
what
In the secondary visual cortex (__), many cells still respond best to lines, images, & sine wave gratings, but some cells respond selectively to circles, lines that meet at a right angle, or other complex patterns.
V2
Cells in the ____ ____ ____ respond to identifiable objects.
inferior temporal cortex
Cells in the temporal cortex respond according to what the viewer ____, not what the stimulus is physically.
perceives
In the temporal cortex cells that respond to the sight of a particular object continue responding about the same way despite changes in its position, size, and angle. Presumably these cells somehow learn to recognise all the different views as being the ____ object.
same
Damage to the shape pathway of the cortex leads to specialised defects. An inability to recognise objects despite otherwise satisfactory vision is called ____ ____ (meaning visual lack of knowledge). It usually results from damage in the temporal cortex.
visual agnosia
Although the brain does not have a specialised area for seeing flowers, fish, birds, clothes, food, or rocks. However, three types of objects do produce specific responses. One part of the ____ ____ (next to the hippocampus) responds strongly to pictures of places, and not so strongly to anything else.
parahippocampal cortex
Again, part of the ____ ____ of the inferior temple cortex, especially in the right hemisphere, responds strongly to faces, much more than to anything else.
fusiform gyrus
Also an area close to this face area responds more strongly to ____ than to anything else. The brain is amazingly adept at detecting biological motion – the kinds of motion produced by people and animals.
bodies
____ ____ is extremely important. For civilisation to succeed, we have to know who to trust and who to distrust, and that distinction requires us to recognise people that we haven’t seen in months or years.
Facial recognition
When you meet people you haven’t seen in years you will ____ many of them, despite the fact that they have gained weight, become bald, or dyed their hair. Computer programmers who have tried to build machines to recognise faces have discovered the difficulty of this task that seems so easy for people.
recognise
Human newborns come into the world predisposed to pay more attention to faces than other stationary displays. That tenancy supports the idea of a built-in ____ ____ ____.
face recognition module
The ____ concept of “face” is not like an adults. Evidently, a newborns concept of “face” requires the eyes to be on top, but the face does not have to be realistic.
infants
Developing good facial recognition requires ____, and as with other learning, it occurs best during early life.
practice
