Flashcards
Extrastriate cortex and balance
Cards in this deck (21)
- 1What happens to to visual information after processing in area V1?splits into two pathways which both pass through the V2 area (extrastriate)
- ventral pathway = what pathway (object recognition) -> area V4 -> inferior temporal cortex
- dorsal pathway = where pathway (vision processing for action) -> MT+MST -> intraparietal cortex - 2What is coded for at V1?simple visual features
- contrast
- line orientation
- brightness
- colour
- movement
- disparity (depth cues) - 3Explain the further visual processing that occurs in the extrastriate cortex- simple stimuli are processed together to form more complex perception
- 4Explain extrastriate processing in the ventral (what) streamIn area V2
-thin stripes - colour
- interstripes - edge detection ->
area V4
- complex form and perceived colour -> inferior temporal cortex
-object recognition and perception - 5Explain extrastriate processing in the dorsal (where) streamV2
- motion and disparity ->
MT + MST
- global motion through space -> intraparietal cortex
- vision for action
-vision for eye movements - 6What occurs when there is damage to the inferior temporal cortex and describe the two forms of itVISUAL AGNOSIA occurs
- aperceptive - can't copy or match objects (can't integrate visual features)
-asssociative - can't interpret, understand or assign meaning to objects (problem w/ recognition)
e.g. STROKE - 7What is the dorsal pathway important for? (where)- reaching and grasping w/ hands
- directing eye movements
-> spatial constancy
stable view of the world despite eye movements leading to constant retinal motion - 8What happens when there is damage to the intraparietal cortex?Damage to left parietal lobe - no effect
Damage to right parietal lobe - hemi-neglect of left visual field - patients can only 'see' right visual field e.g. only draw right side of house
- due to left PL only seeing right visual field while right PL sees whole of visual field due to interhemispheric connect. - 9Explain bottom-up and top-down processingbottom-up processing - processing of sensory (exogenous) information
top-down processing - processing w/ internal (endogenous) info - interpretation of visual info is heavily influenced by
- expectation
-context and learning - 10How is processing combined?bottom-up and top-down processing is combined to create a conscious visual and motor experience
e.g. directing gaze and body movements to follow a target - 11Explain what binding is and describe the three challenges associated with thisBinding is the integration of diverse neural information to from a total cohesive experience
!) integrating different visual properties into one perception at a location e.g. complex object in single place
2) integrating bottom-up and top-down
3) binding features processed individual - 12Give an example of how a single object can be coded and the problem associated with this6 [populations of neurons could code for each feature - combinations of these populations can therefore code for object (e.g. colour, shape, position)
. H/e if more than one object - how can features be assigned to each object? - 13Describe the binding problem 1segregation problem - how are complex patterns of sensory input allocated to discrete objects
- 14Describe the binding problem 2The combination problem
- how are various features combined into one perception - 15Describe some of the selected theories associated with the binding problem- timing of inputs - synchronized activity of different populations indicate that two features are 'bound'
- oscillatory potentials may be important - cortical gamma waves - 40 hz
- coincidence detection e.g. NMDA R
- Location of inputs - binding is linked to a common location in VF - relies on topographic representation - 16Why is integrating sensory inputs important in the body- know where are body is in space e.g. proprioception
- which direction we are headed
- where our limbs are relative to our body
- forces acting on our body e.g. co-ordination - 17Explain how vision (dorsal) is important in body co-ordination- encodes
. where objects are relative to us
- stable view of the world
- vision to guide eye movements
- vision for action e.g. navigation , reaching - 18Name the two other body systems important in proprioception and why they're important- the vestibular system
- rotation anfd translationd of the head - sense organs
- the somatosensory system
- proprioceptors and cutaneous inputs
e.g. muscle spindle - stretch
Golgi tendon organs - tension
Joint receptors - angle - pressure sensors - 19What is efference copy and what are the pros and cons?Efference copy is the internal copy of the outflowing motor signal - it is stored in the brain
Advantages - fast movements - don't have to wait for sensory input
. movements not affected y external forces
Dis - no room for unexpected change, no absolute reference, not useful for fine manipulation - 20What is efference copy used for- EF is used for ballistic movement - very fast movements which have a predictable motor outpit
- 21What are sensory organisation tests and what do they measure?Measure postural control and body sway (force/tilting platforms)
e.g. computerised dynamic posturography (CDP)
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- Physiology (Physiology of excitable cells) Flashcards on Extrastriate cortex and balance, created by Charlotte Pedley on 04/01/2019.
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- Charlotte Pedley
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