Dysfunction in Perception Flashcards
Sensation
Being able to sense external or internal stimuli
Perception
Being able to interpret the sensory information
(perceptual deficits can occur without sensory impairment)
V1 Primary Visual Cortex
Visual information travels from the retina, through subcortical areas to V1
First part of cortex to receive visual information.
Lesions in V1
Sometimes retain visual abilities: blindsight
Spatial navaigation and coordination are good: able to avoid obstacles and interact with environment
Secondary visual cortices
Receive most visual info from V1
Process visual information with regards to form, motion, and shape
Akinetopsia
Loss of visual motion perception
Bilateral damage to V5, she can assess where things are going but needs to effortfully think about how things are moving
Seeing in less FPS
Visual association Cortices
Receive input from visual cortex and from cortices, allowing for multisensory integration
Ventral stream
from V1 to ventral prestriate cortex to inferotemporal cortex
Dorsal Stream
from V1 to dorsal prestriate cortex to posterior association cortex
“What vs Where” theory
Ventral stream = “What pathway”
Dorsal stream = “Where pathway”
Damage to “what” pathway
No difficulty reaching for objects they have difficulty describing
Damage to “where” pathway
Difficulty accurately reaching for objects they have no difficulty describing
“Action vs Perception” theory - by milner + goodale
Dorsal stream: direct behavioural interaction with objects (Action)
Ventral: mediate conscious perception of objects (Perception)
Agnosia are caused by damage to _____
Ventral stream damage
What are agnosias?
Loss of ability to recognize objects or shapes
Perceptual deficits, not sensory
Apperceptive agnosia
Failure in object recognition linked to problems in perceptual processing
Can recognize normal views of objects but impaired on unusual views
May find difficulty in copying objects
Associative agnosia
Normal visual perception but unable to use visual information to recognise things
Cannot access names or other information about objects presented visually
Which areas involved in face processing
Network of occipito-temporal areas
Fusiform face area, occiptal face area, anterior temporal cortex
Prosopagnosia
Failure to recognize faces with intact object recognition
Can describe characteristics of a face without recognition
can be acquired or from birth
Prosometamophopsia
Disorder in which faces appear to be distorted
Can involve one or both sides of the face
Shows that there must be some part of brain specfic to facial recognition
