chapter 4 part 2 Flashcards
organization of the striate cortex
cortex is organized into location columns and orientation columns that are perpendicular to the surface of the cortex, so that all of the neurons within a column have their receptive fields at the same location on the retina and prefer stimuli with the same orientation
organization of orientation columns
neurons preferred orientations change in an orderly fashion across the cortex - 90 to 85 to 70 etc
organization of location columns
one location column is large enough to contain orientation columns that cover all possible orientations meaning it can represent any oriented edge or line in a specific area of the retina
hypercolumn
a location column with all of its orientation columns - receives information about all possible orientations that fall within a small area fo the retina
tiling
when adjacent and overlapping location columns work together to cover the entire visual field to represent a scene
extrastriate cortex
visual areas outside the striate cortex - in the occipital lobe and beyond - v2, v3, v4, v5
as we move to higher extrastriate areas, the receptive field sizes of neurons increase
object discrimination problem
monkeys trained to recognize objects in two choice tasks - rewarded for recognition
monkeys who had had their temporal lobe (what pathway) removed found the task very difficult
landmark discrimination task
monkeys were trained to recognize a landmark (something like a cylinder shape) as the location of a food reward
monkeys who had had their parietal lobes(where) removed had difficulty completing the task
ventral and dorsal pathways
ventral - what - temporal, lower part of brain
dorsal - where - parietal - upper part of brain
pathways have connections between them
double dissociation
when damage to one area causes function a to disappear but function b to remain and damage to a different area causes the opposite effect, we can conclude that function b and a operate independently
patient df
patient who suffered damage to ventral pathway - could not match orientation of a card held in her hand to orientations or a slot - recognition (how pathway)
but ability to place the card in the slot (action) was still intact (action pathway)
ability to judge visual orientation and coordinating vision and action different processes
inferotemporal cortex
area of the temporal lobe that contains neurons with receptive fields large enough to encompass entire objects in the visual field
- whole shapes - like hands and faces
medial temporal lobe
collection of structures important for memory - parahippocampal cortex, entorhinal cortex and hippocampus - receives signals from the inferotemporal cortex
neurons in this area respond to perceiving objects as well as remembering the same objects/events