Attending and Spatial Brain

Question 1

What is attention?

Answer 1

The ability to select the stimulus, focus on it, sustain that focus and shift that focus at will

Question 2

What three different forms does space exist in in the brain?

Answer 2

1. Locations on sensory surfaces (e.g. the retina; retinocentric space)
2. Location of objects relative to the body (egocentric space)
3. Location of objects relative to each other (allocentric space)

Question 3

What do we use in order to locate things in space?

Answer 3

cross modal perception integrating information from sight, sound touch ect.

Question 4

What is the selection of attention based on?

Answer 4

Relevance or importance to current goals

Question 5

Where does attention tend to be directed towards?

Answer 5

Locations in soace

Question 6

What is the spotlight metaphor for attention?

Answer 6

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

Question 7

Do eye fixations and attention always go together?

Answer 7

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

Question 8

What is exogenous control of attention?

Answer 8

• 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

Question 9

What did Posner show about the relationship between reaction time and presentation of a cue?

Answer 9

• 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

Question 10

What is inhibition of return?

Answer 10

• 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

Question 11

What is endogenous control of attention (internal attention)

Answer 11

Visual search: scanning the environment to find something yu are looking for

Question 12

When is visual search the quickest?

Answer 12

when finding an image that only differs on one feature (e.g. orientation)

Question 13

Why does it take longer to find a target that differs in more than one feature to the other targets?

Answer 13

Because you have to scan through lots of different items

Question 14

What is the feature integration theory (FIT)?

Answer 14

• 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

Question 15

Where is the where (dorsal) pathway located and what is important in?

Answer 15

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

Question 16

Where is the what (ventral) pathway located and what is it important in?

Answer 16

The ventral pathway reaches down into the temporal lobes and processes information that leads to the recognition and identification of objects

Question 17

Why are parietal lobes also called the now route?

Answer 17

Because they bring together different types of spatial representation that are needed for action

Question 18

What did Corbetta and Sherman find when they looked at deployment of attention when people were scanned in an fMRI scanner?

Answer 18

• 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)

Question 19

What does it mean that in humans there may be hemispheric asymmetry of parietal lobes?

Answer 19

• 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)

Question 20

What is the most widely quoted definition of neglect?

Answer 20

‘Fails to report, respond to or orient to novel or meaningful stimuli presented to the side opposite a brain lesion’

Question 21

Is neglect due to a sensory or motor impairment

Answer 21

no but they can often co-occur

Question 22

What is neglect also known as?

Answer 22

unilateral neglect, spatial neglect or hemispatial neglect

Question 23

Do patients fail to attend to information on the same side of space or the opposite side of space to their lesion

Answer 23

• the opposite side

- e.g. a right sided lesion would effect the left side of space

Question 24

When is neglect most prominent?

Answer 24

Following stroke to the right hemisphere of the human brain

Question 25

What are the different mechanisms neglect could arise from?

Answer 25

- loss of neurons dedicated from representation of that space - a failure to shift attention to that side - some combination of the two

Question 26

What is the neuroanatomy of neglect?

Answer 26

- cortical areas damaged in spatial neglect are mainly in the parietal lobe (right parietal areas and also in some frontal area) - the lesion is in the parietal association cortex which integrated multiple sensory signals and has extensive connections with frontal areas

Question 27

What did Mort et al find when he took scans of many neglect patients?

Answer 27

- That neglect was due to a specific overlap of regions in the right angular gyrus But this finding is disputed: generally lesions in the parietal lobe will lead to neglect

Question 28

Can you get neglect following left parietal lesions?

Answer 28

Yes but not as common

Question 29

What modality most commonly shows neglect?

Answer 29

Visual modality

Question 30

Can you get multimodal neglect?

Answer 30

YEs

Question 31

What are clinical tests of neglect?

Answer 31

- line bisection - Albert's lines: cross all the lines you can perceive - star cancellation: cancel the stars you can see - copy a drawing - draw from memory

Question 32

How are the different types of neglect usually defined by?

Answer 32

Double dissociations

Question 33

What is perceptual versus representational neglect?

Answer 33

- Perceptual neglect: if participant cannot perceive one half of space - representational neglect: neglect that affects memories of scenes - the brain contains different references for spatial and imagined events in external space

Question 34

What experiment provides evidence for the double dissociation between perceptual and representational neglect?

Answer 34

The Piazza del Duomo experiment

Question 35

What is the neglect for near versus far space and what evidence is provided for this?

Answer 35

There is a double dissocation between near space (line using pen and paper and far space (which is spared) when tested with a light pointer - PET in normal participants: Weiss et al., near space and far space represented differently in space

Question 36

What is the difference between neglect for personal versus peri personal space?

Answer 36

- there is a double dissocation between personal (bodily) space and near space) - Body neglect - failure to groom left of body, notice position of limbs or feel pain in the left limbs - near space neglect: visual search of array of external objects: movements just attend to the right side of space

Question 37

What is the difference between within object and between object neglect?

Answer 37

- Some patients attend to objects on the left side of space but omit to attend to one half of the object itself (object based neglect - STG - superior temporal gyrus) - this forms a double dissociation with: - space based neglect - angular gyrus: will only copy image from one half of the picture

Question 38

How do we know neglect is a disorder of attention and not low-level perception?

Answer 38

- neglect patients still activate visual regions in occipital lobes for the information that they claim not to be aware of - they are often able to detect objects on the lect if cued there

Question 39

What does the phenomenon of visual extinction suggest?

Answer 39

Different perceptual representations are competing for attention (and visual awareness)

Question 40

What is neglect and extinction?

Answer 40

When two stimuli are presented simultaneously to the left and right of the patients midline the left target typically extinguished

Question 41

What is the burning house experiment

Answer 41

although participant claims not to be able to see the smoke coming out the window they answer that they would prefer to live in the house that isn't on fire

Question 42

What is egocentric neglect?

Answer 42

With respect to the observer. E.g. line bisection

Question 43

What is allocentric neglect?

Answer 43

with respect to another extra personal event; e.g. Piazza del Duomo

Question 44

What is object centred neglect?

Answer 44

With respect to a principal axis in the canonical representation of an object

Question 45

What is Prism Adaptation Rosetti in the rehabilitation of neglect?

Answer 45

Patients wear prism lens glasses that shift their view to the right. When asked to point at objects they make errors by missing to the right. However, visual feedback allows them to compensate for the errors and correct towards the left

Question 46

What are the different roles of the parietal lobes and the hippocampus?

Answer 46

- the parietal lobe is primarily concerned with linking sensory and egocentric maps of space to create representations of observable environment - hippocampus stores long term representations of space that need not be presently observed or even viewpoint specific - these may sometimes work together; e.g. in the Piazza del Duomo experiment the hippocampus may store the map of the square and the parietal lobes may superimpose a viewpoint onto this map

Question 47

What did Green and Bavelier find about video games and attention?

Answer 47

- participants trained in action video game much better at detecting contrast sensitivity, better at visual search task and significantly better at mental rotation tasks - people who play at least 5 hours of action video games per week have fewer activations with areas devoted to attention compared to people who rarely played video games - this is a sign their brains were performing the task more efficiently

Question 48

What is TOVA (the test of variables of attention?

Answer 48

- TOVA assess 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 presented in lower position) - in one condition the targets are rare and the nontargets appear frequently. The extent to which participants are able to withhold responding to non-targets is a measure of impulsivity

Question 49

What did Dye et al find when they used TOVA to assess impulsivity and sustained attention in young adults who were either non-video game players or habitual video game players?

Answer 49

Found that habitual video game players were significantly higher in both sustained attention of impulsivity paradigm but their accuracy was the same as non-video game players. There was no speed-accuracy trade off. - shows that video game players were overall faster than non video game players in both the sustained attention and impulsivity condition

Question 50

What are cognitive controls?

Answer 50

Set of neural processes that allow us to interact with pour complex environment in a goal direct manner

Question 51

What did Anguera find when e tested the effect of being engaged in game playing tasks in older individuals?

Answer 51

- the working memory is much higher on the group that played the NeuroRacer game - TOVA is much higher in he group that played the NeuroRacer game - they were as good as multitasking as people who did the task for the first time in their 20s - after NeuroRacer training the EEG pattern resembled those of 20 year olds with the key change in the prefrontal cortex - measures of coherence were much better: the different brain areas communicate well with each other

Question 52

What has been proposed to play an important role in the neural processes that underlie multitasking performance?

Answer 52

The dorsolateral prefrontal cortex (FLPFC)

Question 53

What was shown when anodal tDCS pr sham tDCS was applied over the left dorsolateral prefrontal cortex in healthy young adults immediately before they engaged in a 3D video game designed to assess multitasking performance?

Answer 53

- The anodal group showed enhanced multitasking perofrmance and decreased multitasking cost during the second session suggesting delayed cognitive benefits to tDCS