4.2 To understand how executive functions and in particular attention are processed in the brain.

Question 1

Attention

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Answer 1

Is een proces vóór selectief bewustzijn en respons op stimuli. Het is het vernauwen of selectief focussen van het bewustzijn op een deel van de sensorische omgeving of op een klasse van stimuli.

Als sensorimotorische capaciteiten groter worden, worden de processen van aandacht en bewustzijn ook groter.

Question 2

Consciousness

Kolb&Wishaw H22

Answer 2

Is synoniem op een primary level met awareness en op een secondary level met awareness of awareness.

Question 3

Wat is het breinproces van aandacht?

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Answer 3

Top-down proces dat informatie selecteert van een specifiek deel van de sensorische wereld.

Question 4

Wat is het breinproces van bewustzijn?

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Answer 4

Bewustzijn is in tegenstelling niet selectief, het vat alle info samen die relevant is voor het individu en zijn omgeving.

–> Dus bewustzijn geeft de kern van de wereld en aandacht focust op specifieke kenmerken van de wereld.

Question 5

Aandacht

Automatische processen

Kolb&Wishaw H22

Answer 5

• Zijn onbewust,
• direct gedrag komt voor zonder intentie
• Onvrijwillig
• Zonder bewustzijn
• Zonder interferentie met andere activiteiten

Deze processen zijn bottom-up en data-gedreven: het vertrouwt bijna alleen maar op de stimulusinformatie van de omgeving.
Het kan aangeboren zijn maar training kan dit ook produceren.

Question 6

Aandacht

Bewuste processen

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Answer 6

Gecontroleerde processen vereisen gefocuste aandacht en zijn top-down en conceptueel gedreven: het vertrouwt op info dat al in het geheugen zit.

Question 7

Conjunction search

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Answer 7

A serial process, as if a mental spotlight were scanning from one location to another, searching for particular combinations of sensory information.

Question 8

Feature search

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Answer 8

Cognitieve strategie voor het scannen van specifieke kenmerken van stimuli.

In het plaatje van V1 zie je hoe het werkt.
Stimulus wordt geregistreerd in V1 en wordt opgebroken in aparte kenmerkmappen. Die info wordt dan serieel verwerkt in parallelle paden. Aangezien er geen enkel visueel gebied is die verschillende kenmerken van het object integreert of samenvoegt, worden delen van de visuele wereld serieel verwerkt.

Negatieve stimuli (zoals sippe gezichten) worden sneller gedetecteerd dan positieve stimuli (blije gezichten).

Neuronen in de visuele gebieden buiten V1 en V2 reageren anders, afhankelijk of aandacht gefocust is op het bijbehorende receptieve veld.

Question 9

Wat doen cellen in V4?

Kolb&Wishaw H22

Answer 9

Zijn gevoelig voor kleur en vorm, dus verschillende neuronen reageren op verschillende conjuncties van kenmerken.
Een neuron kan leren om selectief te reageren op informatie in het receptieve veld.

De cellen in gebieden V4 en TE coderen ruimtelijke locaties.

Question 10

Divided attention

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Answer 10

Er kan maar een bepaald aantal informatie per keer verwerkt wroden en bij te veel informatie is er een ‘bottleneck’. De capaciteit voor mentale activiteit is beperkt en moet worden verdeeld over gelijktijdige activiteiten.

Question 11

Selective attention

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Answer 11

Een V4-cel reageert optimaal op een gegeven orientatie en kleur, dit is niet exact, dus de cel zal ook reageren op orientaties en kleuren die ongeveer in dezelfde range vallen.

Neuronen in de pulvinar reageren krachtiger op stimuli als de stimuli doelwist zijn van gedrag dan wanneer dezelfde stimuli geen doelwit zijn van gedrag. Dus als er een visuele stimulus is, maar die geen betekenis heeft voor iemand, is neurale vuring laag. Als de stimulus een beloning betekent, worden de cellen actiever.

De pulvinar complex projecteert naar de posterieure parietele cortex, temporale cortex en de PFC. Hij verstoort ruimtelijke aandacht.

Question 12

Parallel processing of sensory input

Kolb&Wishaw H22

Answer 12

Neurons in TE area appear able to process items from cluttered scenes in parallel.
1. One way to do this is by having cells sensitive to complex configurations a neuron would respons to a square above a circle but not to a circle above a square.
2. Another way is to select items serially, a scene would be processed in very brief cycles that allow us to process items in parallel

Question 13

Parallel processing

Cross-model

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Answer 13

Is another way of parallel processing.

This is distributing attention both within and between modalities as we process simultaneously visual, auditory and somatosensory inputs.
When we need to focus on visual stimuli, there is less auditory activation to specific auditory inputs.

Question 14

Parallel processing

Selective attention leads to what kind of activation and decreases in the brain?

Kolb&Wishaw H22

Answer 14

Selective attention leads to increased activation in relevant sensory cortices and decreases in irrelevant regions

Question 15

Parallel processing

Divided attention leads to what kind of activation and decrease?

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Answer 15

With divided attention there is a major change in the left dorsolateral prefrontal cortex. If the PFC is already engaged, say in planning a driving route, attention to one or more of the concurrent tasks will likely be lost.

Question 16

Functional imaging and attention

Right and left parietal cortex

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Answer 16

The right parietal cortex is active when the stimulus is in either the left or the right visual field.

The left parietal cortex is active only when the stimulus is in the contralateral (right) visual field.

These findings may explain why patients with right posterior parietotemporal lesions show more-pronounced contralateral neglect than do patients with left-hemisphere lesions.

Question 17

Functional imaging and attention

Which area is activated during attention to colour

Kolb&Wishaw H22

Answer 17

Region probably corresponding to area V4.

Question 18

Functional imaging and attention

Which area is activated during attention to shape?

Kolb&Wishaw H22

Answer 18

Regions correpsonding to areas V3 and TE.

Question 19

Functional imaging and attention

Which areas are activated during the selective task?

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4

Answer 19

• Insula
• Posterior thalamus
• Superior colliculus
• Orbitofrontal cortex

Question 20

Functional Imaging and attention

Different cortical areas are activated in different attentional tasks

Kolb&Wishaw H22

Answer 20

1. Parietal cortex = activated for attention to location
2. Occipitotemporal cortex= activation for attention to features, such as colour and form
3. Anterior cingulate and PFC= activation during both visual tasks, so attention requires activation of both the anterior cingulate and PFC in addition to activation of specific sensory areas related to a particular modality.
4. Distinct regions in the posterior parietal cortex= attention to different types of sensory input.

Question 21

Networks of attention (Posner and Peterson): 3 concepts of theory

Kolb&Wishaw H22

Answer 21

1. The attention system is anatomically seperate from the sensory systems that process incoming information and produce behaviors.
2. Attention is not a single process but includes networks of distributed anatomical areas.
3. These diverse areas form three distinct networks, each representing a different set of attentional processes: altering, orienting and executive control

Question 22

Networks of attention

Altering network

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Answer 22

The ascending reticular activating system(RAS) in the midbrain functions to maintain alertness.

A key component: the neuromodulating noradrenergic projection from the locus coeruleus in the brainstem to the forebrain, which acts to prepare regions, especially in prefrontal and posterior parietal cortex, for detecting stimuli rapidly.

One of the systems effects: to suppress other cerebral processing, likely by increasing activity in anterior cingulate cortex and related structures.

Question 23

Network of attention

Orienting network

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Answer 23

This prioritises sensory input by selecting a sensory modality (vision, audition, touch) or a location in space. Orienting to a particular stimulus triggers activity in the dorsal system and, to shift attention elsewhere, the ventral system is activated. (plaatje)

2 Orienting networks:
1. Dorsal orienting network
2. Ventral orienting network

Question 24

Orienting network

Dorsal orienting network

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Answer 24

System is strongly right-lateralized.

Operates in top-down process to synchronise visuospatial orienting-system activity

Question 25

Orienting network

Ventral orienting network

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Answer 25

Denk bij deze aan dat je je aandacht bij 1 ding wil houden, het aandacht systeem zorgt er dus voor dat andere stimulus verwerking wordt tegengehouden.

Pulvinar nucleus in the thalamus influences activity in the ventral orienting network.

The ventral orienting network synchronises orienting-system activity with incoming, bottom-up sensory input in primary and secondary regions.

One effect is to reduce the influence of other competing sensory inputs in a winner-take-all competition within various levels of sensory and association systems.

Question 26

Network of attention

Dual executive networks

Kolb&Wishaw H22

Answer 26

2 executive networks:
1. Frontoparietal network: top-down, thought to relate to tasks instructions that are transient at the beginning of a new task.
2. Cingulo-opercular network: shows sustained activity across a task.

The two networks do not correlate strongly with one another.

• Humans are capable of voluntary controlling cognition and emotion. For selfcontrol, we need enhanced activation in the lateral prefrontal and cingulate regions.
• Stress might interfere with frontoparietal executive attentional networks, which leads to an impaired performance on attenional tasks. Study: stress –> decreased activity in DLPFC, anterior cingulate, premotor, and posterior parietal cortices.

Question 27

Mechanisms of attention (in neurons)

Kolb&Wishaw H22

Answer 27

Unattented condition: neurons arrive asynchronous –> small excitatory postsynaptic potentials (EPSPs) that don’t lead to action potentials.

Attended condition: neurons arrive synchronous –> larger EPSPs, which lead to action potentials.

The process of attention increase synchrony globally in the brain. although the optimal signal for inducing synchrony is not entirely clear, many researchers believe it to be a signal of about 40 Hz.

Question 28

“The dark side of attention” (Chung and Marois)

Kolb&Wishaw H22

Answer 28

1. Inattentional blindness
2. Change blindness
3. Attentional blink

Question 29

Inattentional blindness

Kolb&Wishaw H22

Answer 29

Participants fail to notice an event that occurs as they are performing another task.
Gorilla suit

Question 30

Change blindness

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Answer 30

Participant fails to detect changes in the presence, identity, or location of objects in scenes. Like inattentional blindness, change blindness is most likely to occus when people do not expect changes.

Question 31

Attentional blink

Kolb&Wishaw H22

Answer 31

When participants fail to detect a second visual target presentied within 500 milliseconds of the first one. Attention to the first target prevents awareness of the second one, even if it is extremenly conspicouos.

Presumably, the visual system is taxed to the limit by requirring participants to process so much info in such a short time.