Attention & inattention

Question 1

Distinguish between 2 types of attention

Answer 1

Selective attention (filtering the relevant out from the irrelevant) & sustained attention (maintaining processing on the current task = vigilance)

Question 2

Goldberg (1998) found that the sensory response to a peripheral visual stimulus is enhanced when…

Answer 2

The monkey pays covert attention to it i.e. without making eye movements

Question 3

Maintaining vigilance is an active process in as much as it requires protecting…

Answer 3

Current task demands from extraneous & intrinsic distractions

Question 4

Mackworth found that sustained attention levels ___ over time, as indicated by impaired task performance

Answer 4

reduced

Question 5

Sustained attention relies on ascending ___ projections from the locus coeruleus to the ventral attentional network

Answer 5

Noradrenergic (NA)

Question 6

Me and you can experience attention lapses but what are the names of 3 specific disorders of attention? Hint: one is developmental, the other is degenerative & the final one affects young adults

Answer 6

ADHD, Parkinson’s diseases & Alzheimer’s disease, traumatic brain injury & schizophrenia

Question 7

Name 3 syndromes of inattention which arise from focal brain lesions. Which is the rarest? Which arises from a posterior bilateral as opposed to unilateral lesion?

Answer 7

1) Neglect, 2) Extinction & 3) Simultagnosia. Simultagnosia. Simultagnosia

Question 8

Extinction is characterised by a ___ bias in attention towards e.g. the right VF when….

Answer 8

directional. There is competition between the L & R VFs i.e. something is presented in both

Question 9

What sets an extinction patient apart on the Posner task?

Answer 9

They suffer from an unusually large invalidity cost i.e. take much longer to reorient attention from the cued location to the actual, opposite location…WHEN the target location is the extinguished location (usually the left VF)

Question 10

Do left (VF) extinction patients show unusual performance on valid trials of the Posner task or on invalid trials during which the cue directs attention towards the left VF?

Answer 10

No. No i.e. it is easy to move out of the cued extinguished location but it is difficult to move into it when it has not been cued

Question 11

Name 2 examples in which the deficit of extinction can be overcome

Answer 11

1) When 2 balls are joined, extinction patients report seeing a whole barbell or dumbbell, 2) When pacmen images are arranged to form an illusory Kanisza square, patients report seeing more objects

Question 12

Simultagnosia is a symptom of ___ syndrome and is characterised by only being able to see….

Answer 12

Balint’s syndrome. One object at a time when presented 2 or more

Question 13

Humphreys (1994) argues that Balint’s syndrome is a form of __-___ ___. When presented with Luria’s star in white patients report seeing it, yet when…

Answer 13

Non-spatial extinction. Each triangle which forms the star is presented in a contrasting colour e.g. red vs. blue, then patients report seeing only one triangle, not their combination as a star

Question 14

Ballint’s syndrome patients also perceive ___ ___ (feature misbinding) with extended free viewing i.e. not just with brief presentations as in controls

Answer 14

Illusory conjunctions

Question 15

With time can neglect patients recover attention to their neglected VF (usually the left one)?

Answer 15

Yes

Question 16

Give 4 visual perception tasks which reveal deficits in neglect, plus 2 more unusual & interesting tasks

Answer 16

Copying or painting, drawing from memory, reporting items from a room, searching for a target amongst distractors whilst your eye movements are tracked, searching tactically with your eyes shut whilst your hand movements are tracked, imagining Milan Square

Question 17

What is amazing about the Milan Square study is that neglect patient ignore buildings which were…& now report buildings which were…

Answer 17

Previously reported when imagining viewing the square from the opposite end. Previously ignored

Question 18

When neglect or extinction patients view a scene but do not report objects from e.g. the left VF, does V1 respond to objects in this left VF? This means that…

Answer 18

Yes. V1 activation does not equal conscious visual awareness

Question 19

Name some components of neglect i.e. at which exact mechanism might the deficit lie? There may be a directional bias at any one of these levels

Answer 19

It may be a deficit in: 1) egocentric representation, 2) personal vs. extrapersonal space representation, hence the dissociation between these two in some cases, 3) object-centred representation (object-centred neglect), 4) selective attention, 5) spatial WM, 6) sustained attention, 7) motor ouputs, 8) imagery & 9) memory

Question 20

Importantly neglect is an umbrella term for…

Answer 20

Lots of different patients with different precise lesion sites and so different dysfunctional mechanisms

Question 21

Neglect patients are often ___ of their condition. Can the disorder be overcome with training?

Answer 21

Unaware. Yes but only in a stimulus-specific way i.e. there is no transfer to other everyday stimuli

Question 22

Neglect has been found in many different frames of reference e.g. everything to the left of…

Answer 22

The head vs. eye vs. body midline may be ignored

Question 23

N.B. neglect is not always as severe as an inability to consciously perceive the left side of space. Instead it may just be that…

Answer 23

RTs to stimuli presented in the L VF are increased

Question 24

Object-centred neglect is very ___

Answer 24

rare

Question 25

Neglect may reflect an inability to pay attention to the left VF e.g. like looking through frosted glass or simply a directional…

Answer 25

Bias in visual processing towards the right hemisphere

Question 26

The severity of the neglect deficit can be increased by…. This supports the ___ ___ explanation

Answer 26

Increasing the no. of distractors presented. Directional bias

Question 27

Attention to the left vs. right VFs in healthy controls may reflect a push-pull mechanism whereby…. Therefore, neglect reflects a ___ ___

Answer 27

the more attention is delivered to the R VF, the less attention is delivered to the L VF. Directional imbalance

Question 28

The directional bias H1 is supported by Corbetta (2005) who found…

Answer 28

Asymmetry in dorsal attention regions in right inferior parietal stroke patients i.e. lots of activity was found in left but not right dorsal attention networks

Question 29

Bays (2010) found that by increasing the luminance of green squares in the left VF & decreasing the luminance of right VF-presented green squares, neglect patients…

Answer 29

Began to neglect the right side of space relative to the left! I.e. reducing left vs. right VF competition reduces the neglect deficit, supporting the directional H1

Question 30

Using neuroimaging Bays (2010) found that brain activity shifted towards the usually neglected VF as…

Answer 30

The salience of stimuli in the non-neglected VF was reduced

Question 31

Even when no left vs. right attentional bias is implicated, neglect patients with right parietal & frontal lesions show…(Husain, 1997)

Answer 31

A larger & longer attentional blink i.e. the P(of patients detecting T2 after seeing T1) is reduced to a greater extent & for longer than in healthy controls

Question 32

Neglect patients are also impaired on “inhibition of return” i.e. keeping track of spatial locations. E.g. they…(Malhotra, 2005)

Answer 32

persist on identifying targets (e.g. Os amongst Qs) which they have already identified in the right (ipsilesional) VF

Question 33

Neglect patients are also impaired at maintaining non-spatial ___ attention & show a directional ___ deficit. TSB the finding that…(Mattingley, 1998)

Answer 33

Sustained. Motor. Leftward reach to a left visual target is slower to be initiated than in controls. Rightward reach to a left visual target is not slower to initiate than in controls

Question 34

In sum, neglect patients show both spatial deficits in… & nonspatial deficits in…

Answer 34

Spatial deficits: Attention, shifts in covert attention, keeping track of spatial locations, initiating left vs. right motor actions. Nonspatial deficits: attentional blink, sustained attention

Question 35

What drug can we use to enhance sustained attention? Upon what neural structure does it act? (Avery, 2000)

Answer 35

Guanfacine: an alpha-2, noradrenergic (NA) agonist. Dorsolateral PFC

Question 36

Also, when administered to neglect patients without extensive PFC damage, guanfacine improves…(Malhorta, 2006)

Answer 36

Space exploration e.g. patients mark off targets in the left VF as well as the right VF

Question 37

In contrast to guanfacine, rotigotine is a ___ agonist which reduces ___ or selective attention (a 12.8% improvement in finding left targets) but not…

Answer 37

Dopamine, neglect, sustained attention