LECTURE 26 - closed loop control - - visual pathways Flashcards
what are the two streams of the visual pathway ?
dorsal and ventral stream
where does the dorsal stream travel ?
V1 (primary visual cortex) to PPC (posterior parietal cortex)
where does the ventral stream travel ?
V1 to inferotemporal cortex
what does the dorsal stream support ?
vison for action
what does the ventral stream support ?
vision for perception
what is prosopagnosia ?
- face blindness is a neurological disorder characterized by the inability to recognize familiar faces
- people with prosopagnosia may have difficulty distinguishing between faces, remembering faces, or associating faces with names or identities
what is the important case study of the closed-loop control : visual pathway and prosopgnosia ?
- the monkey study
- had names associated with each chimpanzee based on the features of the face
- can see features but cant put it all together
what is one piece of evidence that shows we have a dorsal and ventral aspect
study by Ungerleider and Mishkin in the 1980s, the researchers trained monkeys to perform two different tasks: one involving the perception of the location of an object and the other involving the perception of the object’s identity
what is a region of ventral visual pathway which is responsible for this now process ?
fusiform face region
what is visual agnosia ?
a neurological condition characterized by the inability to recognize or interpret visual information, despite normal functioning of the eyes and optic nerves
can DF identify different shapes or object features ?
cannot
can DF reach out and grasp objects properly
yes
does object agnosia use vision for motor contact ?
yes, fully intact use of vision for motor contact (movement)
what is the first classic and simple study looking at DF’s visual abilities ?
model, copy and memory drawing of apple and book (milner and goodie)
describe the visual agnosia and DF study :
- DF was asked to look at an object (so these would be paper drawings) and then in response, DF is asked to copy them using paper and pencil in order to copy the image
what is the main point of the DF study ?
- that DF has an idea, she has a memory of what these objects look like, however when she is physically looking at those things she’s only unable to recognize these elements
what is DF ?
Patient DF is a woman with visual apperceptive agnosia
what are the two tasks in visual agnosia ?
PT and AT
what does PT and AT stand for ?
PT = perception task
AT = action task
what is the perception task ?
involves presenting a patient with a series of simple geometric shapes, and asking them to identify or match the shapes