Attention and consciousness ch.9

Question 1

Subdivision of attention

Answer 1

1. vigilance
2. arousal
3. divided attention
4. selective attention

Question 2

Vigilance

Answer 2

Sustain attention over time

Question 3

Arousal

Answer 3

Alertness, which improves through the day, reaching a peak in early evening, and then diminishing towards bedtime.

Question 4

Divided attention

Answer 4

Where there are at least two channels of input and the respondent has to try to “attend” to each one.

Question 5

Selective (focused) attention

Answer 5

What allows us to focus on one channel at the expense of others.

Question 6

Orienting response

Answer 6

A spontaneous reaction to a stimulus in which the head and/or body are moved so that the source of the stimulus may be examined.

Question 7

How to investigate selective attention experimentally?

Answer 7

dichotic listening paradigm; presented with two simultaneous streams of auditory input. The listener should then “shadow” one channel by repeat aloud the stream of words in the “attended” channel in order to assess which information in the unattended channel “gets through”

The “attended” channel have better recall, but in situations where the unattended channel material is “salient”, it is often recalled.

Question 8

Treisman´s model

Answer 8

although a particular channel might be selected early on in the processing stream, the unattended channel is not being “shut down”, but received less attentional effort than the attended channel.

Question 9

P300

Answer 9

a positive wave in EPR occurring roughy one-third of a second or later after stimulus presentation. This “late” wave seems to be related to the contextual meaning of the stimulus, and shows that attention can modify the brains response for some time after a stimulus has been presented.

Question 10

N250

Answer 10

Negative wave in EPR, with a latency of about 250 ms, if the face is meaningful, famous or familiar.

Question 11

N170

Answer 11

Is strongest to facial images, including animal and cartoon faces.

Question 12

Brain structures and attention

Answer 12

No single attention “center”,, but several regions forms a distributed neural network that is collectively responsible. the network comprises brainstem, midbrain, and forebrain structures, and impaired attention may result from damage to any of these.

Question 13

The ascending reticular activating system (ARAS)

Answer 13

A brainstem structure; consist of neurons whose axons send through the midbrain to influence forebrain structures including the cortex.

It consist of several distinct neurotransmitter systems; cholinergic pathway, noardernergic pathway, dopaminergic pathway and serotonergic pathway

Question 14

Neurotransmitter system ARAS

Answer 14

• cholinergic pathway
• noardernergic pathway
• dopaminergic pathway
• serotonergic pathway.

The axons of many of these neurons divide many times en route to the cortex, and the upshot of this cortical innervation is that a small number of brainstem and midbrain neurons can affect the excitability of virtually every cortical neuron.

Question 15

Damage to ARAS

Answer 15

This system has been implicated in arousal and the sleep-wake cycle, so damage to ARAS will disrupt circadian rhythms and can result in coma, or chronic vegetative state.

Stimulation of the ARAS, will quickly wake a sleeping animal.

AMPHETAMINE are thought to have particular influence on the neurons in the aRAS and the pathway from it to the cortex.

Question 16

The superior colliculli

Answer 16

These are two bumps on the dorsal side of the brainstem in the midbrain region

Question 17

Key role of superior colliculli

Answer 17

Controlling a particular but vital type of eye movement in which object initially in the peripheral field of vision “capture” attention. these are called “express saccades”.

Damage to this part interferes with express saccades but not other slower eye movements.

Question 18

Supranuclear palsy

Answer 18

Disorder affecting the subcortical regions, including the “superior colliculli” -> patients are unable to direct their gaze in normal way, not looking at someone who is speaking or turning to greet an approaching friend.

Question 19

The inferior colliculi

Answer 19

Bumps just beneath the superior colliculi play a similar role in orienting the individual towards “salient” auditory stimuli.

Question 20

The pulvinar region of the thalamus

Answer 20

Appears to play a vital role in filtering material to be attended from the vast amount of sensory input that the brain actually receives.

Question 21

The thalamus (general role)

Answer 21

The thalamus, as a whole, work as a relay station for almost all sensory inputs en route to the cortex, and is therefor ideally situated to serve as a filter.

Question 22

The cingulate gyrus

Answer 22

It appears to be involved in several separate attentional processes: cingulate as a whole provides an interface in which sensory inputs are linked to “motional tone”.

The anterior region of this structure are criticaly involved in response section (can I ignore it or do I need to run away?).

The anterior cingulate becomes active in circumstances in which appropriate “correct” response have to be selected in a deliberate manner. e.g. the troop task.

Question 23

The parietal lobes

Answer 23

Specialized in processing spatial relations and their role in attention.

Parietal damage is associated with hemineglect, an attentional disorder where half of the visual field is ignored. P300 wave is most marked in parietal regions (= might reflect “attentional resource” allocated to a particular task), so the more attention a patient pays to particular stimuli, the larger the resultant P300. Damage to parietal lobe regions > no longer generate P300s.

Question 24

Brain region WM and EF

Answer 24

Dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate

Question 25

Hemineglect

Answer 25

Is a collection of related disorders usually associated with inferior parietal or medial temporal lobe damage. An individual effectively ignores one side of space with respect tot he midline of the head or body = “egocentric neglect” damage to angular gyrus.

Question 26

Allocentric neglect

Answer 26

Form of hemineglect. patient neglect the left or right side of objects regardless of where they appear in the visual field.

Damage: superior temporal gyrus.

Question 27

Epidemiology of hemineglect

Answer 27

9/10 have a right-sided injury and left-sided neglect.

about 10% have left-sided damage and right hemineglect. this is usually less severe, but don’t know why.

Lead to the conclusion that right-sided structures are somehow more critically involved.

Question 28

Anosagnosia

Answer 28

A condition in which a person who suffers impairment following brain damage seems unaware of or denies the existence of their handicap, even if the handicap is severe (blindness or paralysis).

an inability or refusal to recognize a defect or disorder that is clinically evident

Question 29

Why neglect is an attentional disorder?

Answer 29

• when identical objects are presented to both visual fields simultaneously, the “neglect” patient usually fails to report the object in the left visual field (a phenomenon known as “extinction”). However, if different objects are presented one at a time to each side, there will be normal or near-normal recognition even on the “neglected” side.
• attention to objects on the neglected side can be improved by offering rewards for target detection there.
• some processing of materials presented to the “neglect” side occurs even if the patient denies know- ledge of that material

Question 30

Balint syndrome

Answer 30

individual have one or more of a trio of symptoms that could easily be mistaken for blindness

• may be unable o point or reach toward a visual target (optic ataxia)
• unable to shift gaze vulnetmarily to a new target (ocular apraxia)
• unable to easily identify different objects in the same region of visual field presented together (simultanagnosia).

They are not blind, because they can “see” object anywhere in the visual field IF they can direct attention to that location, which is where the problem lies.

Question 31

optic ataxia

Answer 31

may be unable o point or reach toward a visual target

Question 32

Ocular apraxia

Answer 32

unable to shift gaze voluntarily to a new target

Question 33

Simultanagnosia

Answer 33

unable to easily identify different objects in the same region of visual field presented together

Question 34

Balint syndrom (damage)

Answer 34

Occipital-parietal regions

Question 35

Three paradigms of consciousness

Answer 35

• The readiness potential
• Attentional blink
• Inattentional/change blindness

Question 36

The readiness potential

Answer 36

Conscious awareness of the intended movement typically occurred about 200 ms before the movement itself The readiness potential was detectable 350 ms or more before this.

Conscious awareness of the intention to make a movement occurred at least a third of a second AFTER electrical changes anticipating the movement.

Question 37

change blindness

Answer 37

when paying attention to one particular task but other non-task-relevant stimuli are ignored.

Question 38

Global workspace theory

Answer 38

theory of consciousness.

Thought to be an extensive neuronal network probably involving prefrontal, anterior cingulate, and other talamocortical interactions.

Idea: we only have conscious access to a small proportion of all ongoing cognitive processing and there is a constant competition between unconscious to access to consciousness. Operates as “the winner takes it all”.

Question 39

Pinker´s model of consciousness

Answer 39

Three aspects:

• basic phenomenal awareness (subjective experience of something)
• access to information (report on the contents of ones mental experiences)
• Self knowledge (awareness of ones own mental state)