Lesson 4: Cortical organization Flashcards
Why is organization important in the visual system? (2)
- process information about characteristics of objects, such as size, shape, orientation, color, movement, and location in space.
- Process information about different types of objects, such as trees, animals, furniture, etc.
Spatial organization
how different locations in the environment and on the retina are represented by activity at specific locations in the visual cortex.
area V1
striate cortex
retinotopic map
electronic map of the retina on the cortex.
two points that are close together on the object and on the retina will activate neurons that are close together on the brain
What this means is that electrical signals associated with
the part of the tree near where the person is looking (fovea) are allotted 1. more/less space on the cortex than signals associated with parts of the tree that are located off to the side in the periphery.
more.
In other words, the representation on the cortex is distorted, with more space being allotted to locations near the fovea than to locations in the peripheral retina.
Cortical magnification
assignment of a large area on the cortex to the small fovea
fovea = 0.01% of retina’s area
fovea = 8 to 10 % of the retinotopic map on the cortex
cortical magnification factor
size of the cortical magnification
location columns
Are perpendicular to the surface of the cortex, so that all of the neurons within a location column have their receptive fields at the same location on the retina.
orientation columns
Each column containing cells that respond best to a particular orientation.
hypercolumn
A location column with all of its orientation columns
tiling
Each circle or ellipse in the scene represents an area that sends information to one location column. Working together, these columns cover the entire visual field.
Ablation (lesion)
Destruction or removal of tissue in the nervous system
Object discrimination project
pick the correct shape after ablation
temporal lobe = object identity
Called the WHAT pathway
landmark discrimination project
remove the cover of the food well that was closest to the tall cylinder
Parietal lobe = object’s location
called the WHERE pathway and HOW, actions
what other name do we give to the what pathway? (object identification, temporal lobe)
ventral pathway
what other name do we give to the where pathway? (object location, parietal lobe)
dorsal pathway
neuropsychology
the study of the behavioral effects of brain damage in humans.
double dissociation
-which involves two people: In one person, damage to one area of the brain causes function A to be absent while function B is present; in the other person, damage to another area of the brain causes function B to be absent while function A is present
-confirm the areas are independent
modularity
the idea that specific areas of the cortex are specialized to respond to specific types of stimuli
inferotemporal cortex- monkey
selective face neurons
fusiform face area in humans - FFA - Temporal lobe
specialized to respond to faces
prosopagnosia
difficulty recognizing the faces of familiar people
Parahippocampal place area - (PPA)
activated by pictures depicting indoor and outdoor scenes
extrastriate body area - (EBA)
activated by pictures of bodies and parts of bodies
(but not by faces)
Distributed representation
occurs when a stimulus causes neural activity in a number of different areas of the brain, so the activity is distributed across the brain.
Distributed representation of multidimensional stimuli
- we respond to other aspects of faces (ex: emotional, attractive, where they are looking, how it moves, if it’s familiar)
2.Pain
H.M.
Man who removed both sides of his hippocampus to reduce epileptic seizures
Findings H.M.
eliminated seizures but also eliminates the ability to store experiences in his memory. This is because the hippocampus is important to store long-term memories.
what structures are important for memory?
Medial temporal lobe (MTL) structures, such as the parahippocampal cortex, the entorhinal cortex, and the hippocampus.
mind–body problem
How do physical processes like nerve impulses (the body part of the problem) become transformed into the richness of perceptual experience (the mind part of the problem)?
expertise hypothesis
proficiency in perceiving certain things can be explained by changes in the brain caused by a long exposure, practice, or training
