3: The Spatial & Attending Brain Flashcards
define: retinocentric space
Locations on sensory surfaces
define: egocentric space
Location of objects relative to the body
define: allocentric space
Location of objects relative to each other
does the brain regard space as a single, continuous entity?
no
what is cross-modal perception?
integrating information from sight, sound, touch…
what is attention selected on?
relevance and importance to current goals
what does the spotlight analogy tell us about attention?
Spotlight may move from one location to another (e.g. in visual search).
It may zoom in or out (narrow or wide “beam”), e.g. if attending to words or attending to central letter in a word
what is endogenous attention control?
internally guided
what is exogenous attention control?
externally guided by stimuli
define: inhibition of return
slowing of speed of processing when going back to previously attended location
how does attention to images change if something is wrong with them (even if we cannot perceive this problem)
Radiologists looking at scans of bodies - radiologists could ‘sense’ something was wrong even when they couldn’t identify it - they would spend longer on these scans
how does feature intergration theory explain perception
our brains first break down objects into simple features (eg colour, shape) and then, with the help of attention, integrate these features to form a complete perception of the object.
what is a pop-up in feature integration theory?
If an object has a unique perceptual feature, then it may be detected without the need for attention
are pop-up items affected by the number of items to be searched?
no
what leads to serial searching requirements in feature integration theory
If an object shares features with other objects (eg all red triangle and one red square)
what is the dorsal parietal pathway involved in?
processing information about where an item is located and how they might be acted on (ag grasping)
what is the ventral temporal pathway involved in?
involved in the recognition and identification of objects
what area of the brain is associated with endogenous motivation?
dorso-dorsal network (blue) involving lateral intraparietal area and Frontal eye fields
what areas of the brain are associated with exogenous motivation?
ventro-dorsal stream -right tempo-parietal junction and ventral frontal cortex
in what function are the parietal lobes asymmetrical?
space representation
what is the difference in space representation for the parietal hemispheres?
Right parietal lobe contains richer representation of space (left space and some right space)
Left parietal lobe contains an impoverished representation of space (predominantly of right side only)
what is the result of right dominance of spatial representation in the parietal lobe?
The greater spatial specialisation of right parietal lobe means that we all have a tendency to attend to left side of space (pseudoneglect)
how can lesions lead to neglect?
Patients fail to attend to stimuli on the opposite side of space to their lesion (a right sided lesion would affect the left side of the space)
which side stoke is more likely to lead to neglect?
right
what are the 2 mechanisms that lead to neglect?
loss of neurons dedicated for representation of that space
a failure to shift attention to that side
what are 3 tests of visual neglect?
line bisection
cancellation tasks
drawing
what does a double dissociation between perceptual (line bisection) and representational (eg explain a plaza) neglect suggest?
suggests different spatial reference frames for external versus imagined (mind’s eye) space
what does a Double dissociation between near space: line bisection using pen and paper (IMPAIRED) and far space (SPARED) when show?
suggests different spatial reference frames for close versus far space
what are the 5 types of neglect/space
Perceptual vs. representational neglect
Neglect for near vs. far space
Personal vs. peripersonal space
Within objects vs. between objects
Spatial vs. object based neglect
where are activations for near vs far space located?
near: parietal
far: occiputal
what characterises peripersonal/near space neglect?
problems with visual search of array of external objects
what characterises personal/body neglect?
Body neglect = failure to groom left of body, notice position of limbs, or feel pain in the left limbs
what is within object neglect?
when a patient attends to every object but only one part of it (eg draws a picture but only with the right hand side of each object)
define: between object/space based neglect
only attending to objects on one side of a picture
define: spatial neglect
a broader condition where an individual fails to attend to one side of the overall spatial environment. It can include both neglect of objects in space (between-objects) and neglect within parts of objects.
what is the difference between between-object neglect and spatial neglect
between-object neglect has a smaller scope than spatial neglect, for BO people may not attend to the left hand side of a desk when tidying but for SN someone does not perceive anything on the left hand side of a wider frame (eg not seeing someone walking on their left)
what is the difference between within-object neglect and object-based neglect?
Within-objects neglect is more specific to the internal structure of individual objects, and object-based neglect emphasizes a consistent pattern of neglect related to objects, irrespective of their position in space.
define: object-based neglect
more broad type of neglect when a patient attends to every object but only one part of it (eg draws a skyline but only with the right-hand side of each building)
define: spatial neglect
individual fails to attend to one side of the overall spatial environment. It can include both neglect of objects in space (between-objects) and neglect within parts of objects.
what are the 2 other names for spatial neglect?
hemispatial neglect
unilateral neglect
define: multimodal neglect
neglect that transcends one sense (eg sound & sight)
where in the brain are lesions most likely to result in neglect?
left parietal lobe
what happens to the visual regions in the occipital lobe corresponding with the neglected area?
they are still activated
define: visual extinction
a patient fails to detect one of two simultaneously presented stimuli (the one more contralateral to the lesion), despite the fact that each stimulus is correctly detected when presented in isolation
what does visual extinction suggest about attention & perception?
different perceptual representations are competing for attention (and visual awareness)
what kind of coding explains the burning house findings?
implicit
what is one treatment of neglect?
prism adaption - patients wearing prism lens glasses that shift their view to the right, visual
feedback allows them to compensate for the errors and correct towards the left, this deviation to the left persists after the prism lenses are removed and this can produce a relatively long-lasting improvement in symptoms
how do video games change object searching?
people who regularly play video games show lower activation in brain when performing a visual search game - showing that their brain is working more efficiently
what is a test of variable attention (TOVA)?
TOVA assesses impulsivity and sustained attention. In this test, participants are required to press a key as fast as possible in response to a target (black square in upper position) and to withhold responding to non-target stimuli (black square presented in lower position).
what do TOVAs with rare targets measure?
sustained attention - the extent to which participants are able to stay on task and respond quickly to rare targets
what do TOVAs with frequent targets measure?
impulsivity - measures the extent to which participants are able to withhold responding to nontargets
how can habitually playing video games influence impulsivity, sustained attention & accuracy?
VGPs were overall faster than NVGPs in the sustained attention and impulsivity condition. This increased speed did not come at the expense of accuracy
where is the ability to multitask located in the brain?
prefrontal cortex
how does playing video games influence working memory?
when trained using video games, working memory improves
what part of the brain is associated with executive functions?
prefrontal cortex
define: coherence
how well different brain areas communicate with each other
how do video games influence coherence?
they improve coherence
