6.3.1 Parallel Processing In The Visual Cortex 2 Flashcards
In one study, investigators examined 14 people who had been born with cataracts in both eyes but had them repaired it ages 2 to 6 months. Although they developed nearly normal vision, they had subtle lingering problems in recognising slight ____ between one face and another.
differences
The ability to recognise faces continues developing gradually all the way into ____.
adolescence
Precision is best for faces similar to familiar faces. Your brain learns the “____” of the faces it sees and then detects small deviations from the average.
average
Face recognition depends on several brain areas, including parts of the occipital cortex, the anterior temporal cortex, the prefrontal cortex, and the fusiform gyrus of the inferior temporal cortex, especially in the ____ ____.
right hemisphere
Damage to any of these areas leads to ____, meaning the inability to recognise faces.
prosopagnosia
Some individuals are poor throughout life at recognising faces, because they were born with a ____ of connections to and from the fusiform gyrus.
shortage
People with prosopagnosia can read, so visual acuity is not a problem. They recognise peoples voices so the problem is not memory. The problem is not vision in general, but something that relates ____ ____.
specifically to faces
When people with prosopagnosia look at a face, they can describe whether a person is old or young, male or female, but they cannot ____ the person.
identify
Although neurons in many parts of the visual system show some response to changing colour, one brain area is particularly important, known as ____ ____.
area V4
The apparent colour of an object depends not only on the light reflected from that object, but also how it ____ with objects around it.
compares
The responses of cells in V4 correspond to the apparent or perceived colour of an object, which depends on the ____ ____.
total context
After damage to area V4, people do not become colourblind, but they lose ____ ____. Colour constancy is the ability to recognise something as being the same colour despite changes in lighting.
colour constancy
Viewing a complex moving object activates many brain areas spread among all ____ ____ of the cerebral cortex.
four lobes
Two main areas that are specially activated by motion are area MT (for ____ ____ ____), also known as area V5, and an adjacent region, area MST (____ ____ ____ ____).
middle temple cortex : medial superior temporal cortex
Areas MT and MST received input mostly from the magnocellular path, which detects overall patterns, including movement over large areas of the visual field. Given that the magnocellular path is ____, MT is also ____.
colour-insensitive
Most cells in area MT respond selectively when something moves at a particular speed in a particular direction. They detect ____ or ____ as well is the absolute speed, and they respond to motion all three dimensions.
acceleration or deceleration
Area MT also responds to ____ that imply movement, such as a photo of people running.
photographs
Cells in the dorsal part of area MST respond best to more complex stimuli, such as the ____, ____, or ____ of a large visual scene. That kind of experience occurs when you move forward or backward or tilt your head.
expansion, contraction, or rotation
These two kinds of cells – the ones that record movement of single objects and the ones that record movement of the entire background – converge their messages onto neurons in the ____ ____ of ____ ____, where cells respond to an object that moves relative to its background.
ventral part of area MST
MST neurons enable you to ____ between the result of eye movements and the result of object movements.
distinguish
Damage to the areas MT and MST result in ____ ____, the ability to see objects but impairment at seeing whether they are moving or, if so, which direction and how fast.
motion blindness
People with motion blindness are somewhat better at reaching for a moving object than at describing its motion. However, in all aspects of dealing with ____ ____, they are far behind other people.
visual motion
Some people are blind except for the ability to detect which direction something is ____. Area MT gets some input directly from the lateral geniculate nucleus of the thalamus. Therefore, even after extensive damage to area V1 (enough to produce blindness), area MT still has enough input to permit motion detection.
moving
