Attention Flashcards

1
Q

Neurologically what is responsible for arousal? How so

A

Thalamus is the key switchboard of the brain, the reticular nucleus forms a sheet around the thalamus. This sheet can gate all information (High arousal, excited) or block all information (no arousal; coma, deep sleep.) The reticular formation in the brainstem regulates the excitability (and thus permeability) can of the reticular nucleus surrounding the thalamus

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2
Q

How is arousal related to attention?

A

Attention and arousal are not the same, but without arousal no attention

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3
Q

Contrast voluntary and involuntary attention (3/4)

A

Voluntary; Endogenous, intentional, top-down, slower

Involuntary; exogenous, stimulus-driven, bottom-up, almost instantaneous

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4
Q

Contrast overt and covert attention

A

Overt attention- attention is directed to the same location as the eyes
Covert attention- attention is directed to another location than the eyes

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5
Q

Which broad brain regions direct top down and bottom up attention?

A

Voluntary (top-down) attention: Dorsal frontoparietal network

Stimulus driven (bottom up) attention: -Ventral frontoparietal network

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6
Q

Name three common neurological problems affecting attention

A

Neglect
Extinction
Ballint’s syndrome

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7
Q

What specific important regions are involved in the top down network?

A

Superior parietal lobe (SPL), Frontal Eye Fields (FEF), Middle Frontal Gyrus (MFG)

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8
Q

What specific important regions are involved in the bottom-up network?

A

TemporoParietal Junction (TPJ), Inferior Frontal Gyrus (IFG), Middle Frontal Gyrus (MFG)

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9
Q

What subcortical structure are also important for what aspects of attention?

A

Disengaging attention: problems when the tempoparietal junction is damaged
Moving attention: Problems when superior colliculi are damaged
Engage attention: Problems when pulvilinar is damaged

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10
Q

Where is damage affecting attention commonly located?

A

TemporoParietal junction

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11
Q

What damage usually results in neglect?

A

Bottom up network damaged; Right TPJ and IFG

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12
Q

What symptoms of neglect are usually shown

A

They generally take in information from the right side (ipsilateral side) and essentially become blind to the left visual field (contralateral side)

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13
Q

How permanent is neglect

A

It is often temporary but extinction often remains (difficulty in pointing out two similar objects in both fields at the same time)

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14
Q

What damage is associated with Ballint’s syndrome?

A

Much more severe: Dorsal posterior lobe

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15
Q

What symptoms are associated with Ballint’s syndrome?

A
  1. Simultanagnosia: unable to consciously see more than one object at the same time
  2. Optic ataxia: trouble with visual guidance reaching for objects
  3. Oculomotor apraxia: problems in making voluntary eye movements to objects
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16
Q

What is the capacity of the visual working and how is this recorded?

A

3-4, through a visual tracking test

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17
Q

What network is causing the limited capacity?

A

Top down attention network

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18
Q

What does the visual search task and the attentional blink task display about voluntary attention?

A

Its slow/ requires time

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19
Q

What does the visual search task display?

A

Conjunction feature search; looking for unique elements to find the object

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20
Q

What is involved in the attentional blink task?

A

Letters are shown in rapid succession (10 per second)
• 2 targets appear within this stream of stimuli (in this case numbers)
• At the end of the trial subjects need to report the 2 targets
• 1st target is called T1. 2nd target is called T2.

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21
Q

What are the usual results of the attentional blink task?

A
  • T1 is almost always reported (in blue).
  • T2 will be detected when presented directly following and long after T1
  • When T2 follows 300ms after T1, attention is too busy processing T1 and then attention blinks
22
Q

What evidence is there that when you give selective attention to one area, it is at the expense of attention to another? (2)

A

When asked to either recount faces and ignore scenes or vice versa, or passive viewing:Attention directed to a face -> higher activation in Fusiform Face Area. Attention directed to scene -> lower activation in FFA. Intermediate activation during passive viewing.
When people perform an easy task, visual motion evokes a strong response in V5/MT. When people perform a difficult task, visual motion evokes no response in V5/MT. Example that early selection takes place at high task load

23
Q

How do the triggers differ in the Posner cueing task?

A

Central cue triggers- voluntary attention; the square in the centre will indicate a side for the square to appear (usually 80% valid) and you can decide whether to use this which will help or hinder your reaction time
Peripheral cue- stimulus driven attention; a stimulus will flash to either the left or the right which will automatically draw your attention to that side without a conscious decision

24
Q

How does the validity of the cue matter?

A

If cue validity is too low, people don’t use the cue anymore in the central cue condition only

25
Q

What are the results of these tests

A

reaction time is quicker in a valid trial, then neutral, then invalid. The central cue (endogenous) is also much slower than the peripheral (exogenous) cue. The time between the stimulus and the cue in CC must be at least 200ms (facilitation) while in PC inhibition occurs when there’s too much time between the stimulus and the target (inhibition)

26
Q

What two EEG-measures sensitive to spatial information were presented?

A

P1 modulation- Positive ERP around 100ms after stimulus presentation; more positive P1 when spatial attention is at the correct location when the stimulus appears
N2PC- Negative ERP about 200ms after the stimulus, contralateral, posterior measuring site; apparent for movements of spatial attention
(Only movements from right to left and vice versa, not up down )

27
Q

What is ISI and how is it relevant to P1 amplitude

A

Inter stimuli interval, Bottom-up attention ( short ISI- attentional boost) and inhibition of return (long ISI) are evident in P1 amplitude

28
Q

what happens when attention is not yet at the correct location, but shifts to a specific location during the task?

A

N2pc activity in visual search tasks

29
Q

What happens if you have a target on the left visual field

A

negative deflection on the right hemisphere at N2pc (on back of the head) 200ms after (contralateral

30
Q

How do we know this is an effect of attention and not simply pop out?

A

Does not occur for non-target pop- out: so really is an effect of attention, not of pop-out

31
Q

If a stimulus was in the upper right corner of the visual field, where would the neuronal activity be in the visual cortex?

A

Ventral left (bottom left)

32
Q

Are these recording reported outside of the parietal, prefrontal and visual cortex? Are there any differences?

A

Attentional effects are visible in LGN (=thalamus), but are less strong than in visual cortex.

33
Q

Where is the signal strongest and where does it get weaker?

A

The signal gets weaker as it goes from the parietal/ prefrontal cortex all the way down to the visual cortex- strongest in V4 then weaker (about half) in V2, then weaker (about half again) in V1 and fairly weak in LGN and thalamus- must be a fairly difficult task and fairly focused to see V1 and LGn modulations

34
Q

What happens if you attend to multiple locations simultaneously?

A

These areas will light up until about 4

35
Q

How does activity differ when four squares move at the same time versus one (large scale changes versus small)

A

When you need to detect large scale changes, a N2PC in LOC and temporal cortex is observed; areas with large receptive fields When you need to detect small scale changes, a N2PC in V4 is observed; an area with relatively small receptive fields
Spatial attention operates at multiple levels in visual and temporal cortex, at the required receptive field size

36
Q

When put through a feature based task (identifying motion or colour) what features were tied to what areas?

A

Depending on the instruction, more activity in V4 (color) or V5/hMT+ (motion) is observed

37
Q

Describe two object-based experiments and what they demonstrate

A

Experiment: is the number of bumps the same? People respond faster if bumps are on the same object, different sides. In line with object-based theories of attention.
Opaque images of a face and a scene or house is placed over each other. FFA activity is generally seen when attention is place on the face and other for the house.- higher level visual and temporal regions

38
Q

What pattern in observed in the size of receptive fields in different brain areas

A

Receptive fields (RF) become larger when going up in the visual hierarchy

39
Q

How many objects can each receptive field hold? What does this induce?

A

A RF can only represent 1 object at a time, as a result, multiple objects can fall within the RF of a neuron, producing competition between objects for representation

40
Q

Describe an effective and ineffective stimulus in an experimental design, mentioning the brain area

A

Monkey can see a red horizontal bar and a green vertical one, when attending to the red one (effective stimulus) it the V4 neurons will fire rapidly, and the V4 neuron acts like it only ‘sees’ the effective stimulus. While when attending to the green bar (ineffective stimuli) it will have some rise in neuronal activity but not nearly to the same extent; the firing rate goes down, the neuron acts like it only sees the ineffective stimulus. When attending to both there is an intermediate firing rate. This shows some receptive fields have bias towards certain stimulus while it doesn’t towards others.

41
Q

How does V1 differ to this?

A

Small RF; No competition, No effect of attention

42
Q

When presenting multiple stimulus in the visual field, how does activity in the two areas differ?

A

In V1 there’s no difference between sequential and simultaneous stimulus presentation
In V4 there is a difference. Simultaneous = more competition = less activity

43
Q

How is this competition resolved in V4?

A

Directing attention to a specific stimulus

44
Q

How did people theorise attention operated in the past? (3)

A

EARLY: early selection of some information, no processing of non-attended information
LATE: late selection of some information, full semantic (=meaning) processing of all information, selection occurs afterwards
ATTENUATION: depending on the amount of attention deployed early or late selection occurs (lots of attention: early; little attention: late)

45
Q

Which of these theories are most correct?

A

Attenuation

46
Q

What evidence is there for early selection? What exceptions are there to this

A

Dichotic learning task- without attention, no semantic processing (no meaning.) Exceptions of hearing your own name (cocktail party effect)

47
Q

What counter evidence is there for late?

A

When the message you’re attending to switched ears, attention also switches rather than continuing to hear the other ear

48
Q

When is early and late selection used?

A

Early- during very difficult task, when you know beforehand what to attend to
Late- during easy task, when you don’t yet know what to attend to

49
Q

How early do effects of attention come in auditive and visual information when you know what to attend too?

A

Auditive: P20-50 effects of attention apparent, very first moment that information arrives in primary auditive cortex
Visual: P1 (P100) effects of attention apparent, almost immediately after information arrives in visual cortex (C1, even earlier also apparent)

50
Q

Does this differ lower in the hierarchy?

A

Nah still pretty early dawg