Attention I

Question 1

selective attention

Answer 1

covert process that allows individuals to select and focus on a particular input while simultaneously suppressing irrelevant or distracting information
2 forms: voluntary + involuntary

Question 2

overt attention

Answer 2

attention same location as the eyes

Question 3

covert attention

Answer 3

attention different location than th eyes

Question 4

Endogenous attention

Answer 4

top-down, intentional, goal-oriented

Question 5

Exogenous

Answer 5

bottom - up, reflex

Question 6

Limited attention

Answer 6

can’t pay attention to everything

Question 7

Inattentional blindness

Answer 7

can’t see shit when concentrated on something

Question 8

Change blindness

Answer 8

can’t see an obvious change

Question 9

reticular nucleus

Answer 9

sheet around the thalamus, Can gate information = high arousal (excitement) or block information = low arousal (drowsiness, sleep)

Question 10

Reticular fomration

Answer 10

in the brainstem regulates excitability of the reticular nucleus perméability

Question 11

Different theories

Answer 11

early selection theory
late selection theory
attenuation theory
conclusion: flexible theory

Question 12

Early selection theory

Answer 12

we select what we want to attend to very early on and ignore unattended info

no higher-level semantic processing.
This implies that the effects of attention should occur early in the visual/auditory
system and non-attended stimuli should not reach higher brain region

Effects of attention should occur
early in the visual/auditory system and non-
attended stimuli should not reach higher
brain regions.

proof: dichotic listening tasks
problem: cocktail party effect

Question 13

dichotic listening task

Answer 13

two different sound stimuli are presented to each ear, the subject is instructed to only attend to one ear
- Can identifiy: change of gender, whether human or robot in the unattended ear
Can’t identify: change of language, if the same word is repeated over and over

Question 14

cocktail party effect

Answer 14

people are able to pick out their names in from the unattended stimuli = implying higher level processing of some unattended stimuli

Question 15

Late selection theory

Answer 15

selection occurs after some higher-level semantic processing

Effects of attention occur late in
the visual/auditory system and non-attended
stimuli can reach higher brain regions.

Question 16

Attenuation theory

Answer 16

combination fo both theories
Some non-attended information can reach higher levels, but is attenuated. Only salient information (one’s own name) is fully selected.

early or late selection depends on the amount of attention given to a stimulus
So a lot of attention = early selection
§ Difficile tasks
§ When you know to what to attend to such as specific colour
§ Weaker neural responses??
○ Low attention: late selection
§ Stronger neural responses
§ Easy tasks
§ When you don’t know what to attend to = don’t know the colour your friend is wearing so you gotta attend to everything

Question 17

Auditive attention

Answer 17

effects of attention can be seen P20-50 : 20-50 milliseconds after stimulus = 20-50 ms on EEG

see on fMRI: we see that attention modulates primary auditory cortex activity, but not subcortical structure

Question 18

Visual attention

Answer 18

effects of attention can be seen P100 : 100milliseconds after stimulus = reaction time is 100ms on EEG

on fMRI: attention modular’s primary visual cortex activity and even subcortical structures LGN

Question 19

Posner cueing task (endogenous variant)

Answer 19

= allows to study attention behaviourally , with a spatial task
2 variants: exogenous and endogenous variants

Endogenous variant
- 3 conditions : valid cue, invalid cue, neutral cue
Important facts:
- participants can choose to use the cue or not
- vue validity matters: if the arrow is not predictive of where the target will appear, people stop using the arrow
It takes time before attention can be moved: people need at least 200ms to move attention to the left or the right. If there is less between cue and target: no cueing effect

Behavioural results:
- Valid cue : RT is faster accuracy is higher (compared to the neutral condition
- Invalid cue: RT is slower, less accurate compared to neutral condition
- effects only present if there is AT LEAST 200ms between cue and target presentation
- effects are only present if cue validity is high enough, at least 70% of the time.

Question 20

Posner curling task (exogenous variant)

Answer 20

2 conditions:

• valid cue: flash of light appears at location where target is going to appear
• invalid cue: flash of light appears at the other, non-target location

3 important facts:
- participants have NO choice to choose the cue or not: cue forces attention involuntarily to move ether left or right
- cue validity does not matter: even if cue is not predictive of target location, attention is still pulled tot he location of the cue
- cue target timing determines attentional effects: works best when less than 200ms, then it’s the opposite?: the valid cue effect changes from a benefit performance decrement if there is more than 200 ms between cue and target = inhibition of return

Results
Valid cue: RT faster, accuracy higher
Invalid cue: RT slower, accuracy lower
cue <200ms: fast, ventral stimulus driven attention network for those first 200 ms
if not: inhibition of return: after 200ms: slow, dorsal, top-down attention network

Question 21

Inhibition of return

Answer 21

suppression of processing of stimuli that had recently been the focus of attention: if more than 200 ms between cue and target

Question 22

Attentional blink test

Answer 22

Letters are shown in a rapid succession with two targets, and must detect when the targets appear: T1= first target, T2= second target

Results:
T1 is accurately reported
T2 is accurately reportes if directly following T1, or more than 350ms between T1 and T2
Low accuracy for T2 id it is presented between 250-350 ms after T1 = attentional blink
(T2 is dropped only if T1 is asked. If T1 is ignored, than T1 blue line becomes T2)

Question 23

Attentional Stream Paradigm (dichotic listening)

Answer 23

Using EEG, even the earliest subcortical signals can be studied ( brainstem evoked potentials, BERs) can be studied
As we can see, attention has no influence on auditory processing in subcortical structures : attention references to whether there is a difference in the evoked potentials depending on the ear that is attended to

Subjects must detect tones that deviate :
- very first moment information arrives in primary cortex: first effects of attention: p20-50:
- 100ms: N1 effects of attention in which the entire auditory cortex is engaged
but no difference between normal and deviant tones in these early ERP

Early selection: p20-50 and N1 same for all stimuli
Late selection: P300: amplified for deviants compared to standard dev
so P300 enhanced only for deviants IN THE ATTENDED EAR, indicting that deviants in the unattended ear are filtered out (evidence of early selection)
MMN

Question 24

MMN

Answer 24

MMN peaks frontally within 150–200 ms poststimulus in auditory stream paradigm
present in the attended and unattended ear : late selection
But AMPLIFIED in attended ear : early selection

Question 25

P300

Answer 25

Late components of attention, amplified for deviants

Question 26

Covert Spatial attention measured by EEG

Answer 26

• if spatial attention is at the correct location when target hits: larger P1 ( 100ms after stimulus onset) and larger N1 (180ms after stimulus onset)

Question 27

What do P1 and N1 reflect in visual attention

Answer 27

P1: reflects V1, V2, V3, V4 activation
P1; reflections visual and parietal regions

Question 28

Covert spatial attention measured by fMRI

Answer 28

fMRI can measure all visual regions
Attention towards a location enhances neural activity, also apparent when attention is directed to two locations at the same time
Attentional effects even in LGN(. but why is it different from the auditory system?)

Question 29

There is biased competition within the receptive fields

Answer 29

Refs become larger when going up the visual hierarchy
Multiple objects can fall within the RF of a reunon, this may produce competition for representation among objects: effective stimulus vs ineffective stimulus

If both effective and ineffective stimulus fall within the RF of the neuron= there is competition
Activity is therefore the average response to effect and ineffective stimuli

If attention is porté towards the effective stimuli: the firing rate is high, neurons act as if only the effective stimulus was in the RF
same goes with ineffective stimuli, the firing rate is low, neurons act as tho only the ineffective stimuli was in RF
THEREFORE attention resolves competition within RFs

Question 30

Effective stimulus for a neuron

Answer 30

the preferred stimulus, producing strong activation

Question 31

Ineffective stimulus for a neuron

Answer 31

the non-preferred stimulus for a neuron, producing weak activation

Question 32

V4

Answer 32

colour-sensitive visual cortical area

Question 33

V5

Answer 33

motion-sensitive visual cortical area

Question 34

Difference between easy task and difficult task seen on EEG

Answer 34

while asked to perform an easy task, the irrelevant information about motion (activated by V5) shows activity : taking in irrelevant info : late selection

while asked to perform a difficult task the irrelevant info about motion does not show activity : early selection

Question 35

MMN, when , what, where, evidence for which theory

Answer 35

150–200 ms after occurrence of stimuli

related to perceptual discriminability

Attention amplifies the magnitude of the MMN: evidence for late selection
•at least some meaning is processed in the unattended ear