visual object and face recognition Flashcards
Explain Milner and Goodale’s reformulation of the ‘what’ and ‘where’ hypothesis for ventral and dorsal stream functions
The traditional ‘what’ and ‘where’ hypotheses suggest that the ventral stream is responsible for object recognition, whereas the dorsal stream is responsible for spatial localization. However, Milner and Goodale’s reformulation of this hypothesis introduced the concept of ‘vision for perception’ and ‘vision for action’ instead
So rather than strictly separating the stream into ‘what’ and ‘where’, they proposed that the ventral stream is involved in ‘vision for perception’. enabling us to understand and recognise objects, including their shape, colour, and textures, as it processes high detail , while the dorsal stream is involved in ‘vision for action’ , providing guiding actions based on visual inputs focusing on location and motion of objects in the environment.m
what stream is responsible for object recognition
ventral stream to do with what we are seeing
what stream is responsible for spatial localization
dorsal stream to do with visually guided motion
what is visual agnosia? and what brain damage is it usually associated with
loss of visual recognition but not loss of visual acuity (you can still see, but just not be able to recognise what you are seeing)
This is a rare condition of selective brain damage. associated with brain damage in ventral cortical areas such as the ventral occipitotemporal cortex (fusiform gyrus).
give an example of what a person with visual agnosia may deficit from
they can draw copies of drawings but are not able to identify what they are drawing.
what is optic ataxia and what regions of brain damage are associated to this condition
problem with visually guided movement with visual acuity, form and colour vision intact
lesions in parietal srea affecting the dorsal stream
does visual agnosia affect the dorsal or ventral stream?
ventral
does optic ataxia affect the ventral or dorsal stream?
dorsal
give an example of what a person with optic ataxia may deficit from
can not angle hand correctly to slip through a slot
threforehave problems with misdirection of arm to object of interesed and assocaited with defective hand orientation and grip formation
what is face perception?
the ability to recognise familiar faces
what are face cells and describe the monkey experiment used to exemplify this
Face cells respond to familiar facial identities, which are located in the ventral occipitotemporal cortex.
they used fMRI to find facial sensitive hot spots (area that responded greatly to faces or facial stimuli) which were then used to determine the coordinates for electrode placement. Recordings from microelectrodes showed that when monkeys were presented with images of faces, the response was really high compared to other non-face images, suggesting they could be face cells or involved in facial stimuli.
what are the cortical areas involved in object and face recognition in humans?
ventral occipitotemporal cortex, including fusiform gyrus
V4
what is prosopagnosia-evidence for face-sensitive cells
a subtype of visual agnosia associated with loss of recognition for individual face identities
what is cerebral achromatopsia?
colour blindness is usually caused by damage to the cerebral cortex rather than damage to the retina of the eye
what is domain general and what is domain specific
domain general: no specific areas associated with face processing and the brain uses similar cognitive processes for perceiving and recognising faces as it does for visual objects. some of these visual processes include attention, perceptual organization and memory
domain specific: there are distinct brain areas dedicated to face processing (separate mechanisms)
