Extrastriate Visual Cortices Flashcards
Where does separation of function start in the visual system? Describe it.
- starts at the retina
- parvo vs magnocellular layers receive inputs from different types of RGCs (midget and parasol)
TRUE or FALSE: RGCs with a large dendritic tree tend to be found int he periphery, whereas small trees are found in the fovea.
TRUE
TRUE or FALSE: P cells are more specialized for motion, whereas M cells are more specialized for form.
FALSE: P cells = form, M cells = motion
TRUE or FALSE: midget cells have small receptive fields and parasol cells have large receptive fields
TRUE
TRUE or fALSE: midget cells have a transient response and parasol cells have sustained response.
FALSE: midget = sustained; parasol = transient
TRUE or fALSE: P cells have low temporal resolution and M cells have high temporal resolution
TRUE
TRUE or FALSE: destruction of the parvocellular layers in the LGN result in loss of motion vision.
FALSE: loss of form
hint: midget cells
TRUE or FALSE: destruction of the magnocellular layers in the LGN result in loss of motion vision
TRUE
what enzyme is marker for colour blobs?
cytochrome oxidase
How does cytochrome oxidase appear in V1 vs V2?
- V1 = blobs
- V2 = stripes (thick, thin, pale)
From where do thin stripes in V2 receive their input? thick stripes? pale stripes?
- thin stripes receive from V1
- thick and pale stripes receive from interblobs
What aspect or vision do thick, pale, and thin stripes mediate?
- thick = motion
- pale = form
- thin = colour
Which stream/cortical lobe is concerned with motion? colour and form?
- motion = dorsal/parietal stream
- colour and form = ventral/temporal stream
Draw a flow chart of information flow from the retina to the association cortex in the visual parietal/ventral stream. Which types RGCs are involved?
slide 9
What functions are visual stimuli mainly separated into?
form, motion, colour
Which area of the brain is specialized for processing motion?
middle temporal cortex (MT)
How does microstimulation of certain neurons in the MT affect vision?
cause a bias towards certain direction of motion
Which are of the brain is specialized for processing the optic flow of motion?
medial superior temporal cortex (MST)
TRUE or FALSE: MT neuron receptive fields area larger than MST neuron receptive fields.
FALSE: MST receptive field larger
Which part of the brain is specialized for form?
ventral temporal stream
Which part of the brain do simple lines activate? complex form?
- simple lines activate central occipital lobe (V1)
- complex forms activate the inferotemporal lobe
TRUE or FALSE: IT cortex demonstrates columnal organization in terms of complex form processing.
TRUE
Which visual stream is responsive to faces?
temporal stream
TRUE or FALSE: cells in the temporal stream respond not only to faces but also apples and clocks.
TRUE: although very small response…maybe because round?
Which structure of the brain is activated when you perceive two faces? a vase?
- faces = fusiform face area (FFA)
- vase = inferotemporal lobe (IT)
What is the parahippocampal place area (PPA) specialized for in vision? What are its preferred stimuli?
spatial memory; stimuli = landscapes, locations, etc.
What is the extrastriate body area (EBA) specialized for in vision?
body parts (that are not faces)
TRUE or FALSE: the temporal cortex’s specialization in vision cannot be modified.
FALSE: can be modified by EXPERIENCE
TRUE or FALSE: bird experts showed more activation in the FFA than car experts in response to faces.
TRUE
