Attending and Spatial Brain Flashcards
What is attention?
The ability to select the stimulus, focus on it, sustain that focus and shift that focus at will
What three different forms does space exist in in the brain?
- Locations on sensory surfaces (e.g. the retina; retinocentric space)
- Location of objects relative to the body (egocentric space)
- Location of objects relative to each other (allocentric space)
What do we use in order to locate things in space?
cross modal perception integrating information from sight, sound touch ect.
What is the selection of attention based on?
Relevance or importance to current goals
Where does attention tend to be directed towards?
Locations in soace
What is the spotlight metaphor for attention?
The spotlight may move from one location to another (e.g. in visual search). It may zoom in or out (e.g. if atending to words or attending to a central letter in a word). Limited capacity: not everything is illuminated
Do eye fixations and attention always go together?
Location of attention is not necessarily the same as eye fixation (e.g. looking out of the corner of your eyes) however, there is a natural tendency for attention and eye-fixations to go together
What is exogenous control of attention?
- Externally guided by a stimulus
- e.g. if you hear a cry for help your attention will move to the space where the sound cam from
What did Posner show about the relationship between reaction time and presentation of a cue?
- no cue: people initially very slow but get better through practice
- cue closely related in time: people were significantly faster at detecting target
- longer time between cue and target: people significantly slower at detecting the stimulus
What is inhibition of return?
- slowing of speed of processing when going back to previously attended location
- When we have been cued somewhere and nothing happens our attention goes somewhere else. It then takes longer to go back to the previous space as it requires more attentional load
What is endogenous control of attention (internal attention)
Visual search: scanning the environment to find something yu are looking for
When is visual search the quickest?
when finding an image that only differs on one feature (e.g. orientation)
Why does it take longer to find a target that differs in more than one feature to the other targets?
Because you have to scan through lots of different items
What is the feature integration theory (FIT)?
- perceptual features (e.g. colour, line orientations) are encoded in parallel and prior to attention
- if an object has a unique perceptual feature then it may be detected without the need for attention - ‘pop-out’
- if an object shares features with other objects then it cannot be detected from a single perceptual feature and attention is needed to search all candidates serially
- ‘Pop-out’ is not affected by the number of items to be searched
Where is the where (dorsal) pathway located and what is important in?
The dorsal pathway reaches up into the parietal lobes and is important in processing information about where items are located and how they might be acted on guiding movements such as grasping
Where is the what (ventral) pathway located and what is it important in?
The ventral pathway reaches down into the temporal lobes and processes information that leads to the recognition and identification of objects
Why are parietal lobes also called the now route?
Because they bring together different types of spatial representation that are needed for action
What did Corbetta and Sherman find when they looked at deployment of attention when people were scanned in an fMRI scanner?
- Found two different routes depending on whether attention is deployed internally or externally:
1. A dorso-dorsal network involving the lateral intraparietal area LIP and frontal eye fields (FEF) when looking for things actively (internally)
2. Ventro-dorsal stream involving right tempo-parietal junction and central frontal cortex that interrupts any cognitive task in order to divert attention away from processing (external attention)
What does it mean that in humans there may be hemispheric asymmetry of parietal lobes?
- Right parietal lobes contain richer representation of space (left space and some right space)
- left parietal lobe contains an impoverished representation of space (predominantly of right side only)
- the greater spatial specialisation of the right parietal lobe means that we all have a tendency to attend to the left side of space (pseudo neglect)
What is the most widely quoted definition of neglect?
‘Fails to report, respond to or orient to novel or meaningful stimuli presented to the side opposite a brain lesion’
Is neglect due to a sensory or motor impairment
no but they can often co-occur