Attention and Consciousness

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Attention and Consciousness
Cognitive Architectures
Based on book Cognition, Brain and Consciousness
ed. Bernard J. Baars
Janusz A. Starzyk
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Introduction

• Attention and consciousness is brain ability to
  focus and select information, and then to
  perceive and understand it, using it to think,
  memorize, recall, feel, plan and act.
• Attentional control mechanism determines what
  will become conscious.
• We can say please pay attention but not please be
  conscious.
• Attentional selection leads to conscious results
  like eye movement leads to conscious observation
  of the event that attracted out attention.
• Consciousness include immediate perceptual world
  inner speech and visual imagery traces of
  present time in memory recalling past
  experiences feeling pleasure, pain, and
  excitement intentions, expectations, and
  actions believes about yourself and the world
  and well defined concepts.
• We are conscious even we do not talk about it
  the sight of falling star, thoughts about our
  friend, difference in sounds pa and ba.
• We control what we are going to be conscious of.
• We can start to read a book
• We can decide to pay attention to this lecture
• We can think about mothers birthday

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Consciousness

• According to Bernard J. Baars
• Contrary to past beliefs, many aspects of
  consciousness are not untestable at all, as shown
  by productive research traditions on topics like
  attention, perception, psychophysics, problem
  solving, thought monitoring, imagery, dream
  research, and so on.

• Figure shows how selective attention selects
  among competing inputs.
• The spotlight in the Friston circle of brain
  hierarchies is guided by frontal and parietal
  cortex but it selects visual cortex input.

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Consciousness

• Polarities between conscious and
• unconscious phenomena
• Conscious Unconscious
• 1. Explicit cognition Implicit cognition
• 2. Immediate memory Longer term memory
• 3. Novel, informative, and Routine, predictable,
• significant events and nonsignificant
  events
• 4. Attended information Unattended information
• 5. Focal contents Fringe contents (e.g.,
  familiarity)
• 6. Declarative memory Procedural memory
• (facts, etc.) (skills, etc.)
• 7. Supraliminal stimulation Subliminal
  stimulation
• 8. Effortful tasks Spontaneous/automatic tasks
• 9. Remembering (recall) Knowing (recognition)
• 10. Available memories Unavailable memories

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Consciousness

• Polarities between conscious and
• unconscious phenomena
• Conscious Unconscious
• 11. Strategic control Automatic control
• 12. Grammatical strings Implicit underlying
  grammars
• 13. Rehearsed items in Unrehearsed items in
• Working Memory Working Memory
• 14. Wakefulness and Deep sleep, coma, sedation
• dreams (cortical arousal) (cortical slow
  waves)
• 15. Explicit inferences Automatic inferences
• 16. Episodic memory Semantic memory
• (autobiographical) (conceptual
  knowledge)
• 17. Autonoetic memory Noetic (intellective)
  memory
• 18. Intentional learning Incidental learning
• 19. Normal vision Blindsight (cortical
  blindness)

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Attention

• The term attention is used when there is a clear
  voluntary or executive aspect.
• We ask people to pay attention and they can chose
  to do so or not depending on their decision.
• Voluntary attention is involved in preparing and
  applying goal directed selection for stimuli and
  responses.

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Attention
Voluntary vs stimulus driven attention

• Automatic attention selects relevant stimuli
  particularly prominent or unexpected.
• Automatic attention can be captured by human
  face, intense stimuli like pain, or unexpected
  events.
• Selective, attention driven by stimuli is
  bottom-up.
• Executive, goal-driven attention is top-down.
• In general voluntary and automatic attention are
  mixed.
• We can train ourselves to respond to telephone
  ring
• When it rings we pay attention is it voluntary
  or automatic?
• Initially it is voluntary, as we are learning to
  respond to it, later becomes automatic

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Attention

• Attention selects information for cognitive
  process
• Selection may be shaped by emotion, motivation
  and salience and is under some executive control.
• Without flexible, voluntary access control,
  humans would not be able to deal with unexpected
  emergencies or opportunities.
• We would not be able to change habitual behavior
  to take advantage of new opportunities.
• Without stimulus-driven attention we would not be
  able to respond quickly to significant events.
• Thus we need both voluntary and automatic
  attention.

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Experiments on attention

• Selective listening
• Subjects were presented with two streams of
  speech one to each ear
• They were instructed to repeat each word out loud
• People only reported hearing one of the two
  different speech streams
• They selectively listen to a single stream at a
  time
• They could switch between the two

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Experiments on attention

• Visual attention is studied using the flanker
  task (Posner 1984)
• Subject focuses on the center fixation point no
  eye movement allowed.
• The stimuli flashes just outside of the foveal
  region of maximum resolution (flank).
• Then a target appears at the site of flank with
  80 probability.
• When the target appears at the expected location
  the response time is faster than without flank.
• When the target appears at the opposite location
  than the flank the response time is slower than
  no flank.
• Attention network task
• This is a generalization of the flanker task to
  test three aspects of attention alerting,
  orienting, executive attention.

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Experiments on attention

• Visual search paradigm (Treisman and Gelade 1980)
• This tests stimulus driven attention.
• The red vertical bar pops out automatically in
  the first image due to effect of parallel search.
• The same bar on the right hand side requires
  serial search and it takes longer.
• Serial search involves voluntary processing by
  executive regions frontal lobes and parietal
  cortex.

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Experiments on attention

• The Stroop color naming test
• This tests reaction time to three different color
  naming cases.
• The first one has written text unrelated to
  colors.
• The second one has written text that correlates
  with colors.
• The third one has written text with words
  different than colors.
• While the first two tasks have a similar response
  time, the third takes much longer.
• The well practiced skill of reading overwrites
  the color naming and requires executive control
  to correct the errors.

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Brain basis of attention

• William James wrote that attention helps to
• Perceive
• Conceive
• Distinguish
• Remember
• Shorten reaction time
• For example attention to a location dramatically
  improves the accuracy and speed of detecting
  target at this location.

• Attention can be based on internal goals (finding
  a friend in the crowd) or external environment
  (alarm sound, bright colors)

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Brain basis of attention

• An example of attention increased sensitivity
• The recorded neurons are located in
  inferotemporal cortex (IT) area for object
  recognition.
• It responds better to some visual objects
  (flower) than to other.
• Study showed that neuron begins firing in
  anticipation of the preferred stimulus at a
  higher rate than for non preferred stimulus

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Brain basis of attention

• Brain must constantly select between competing
  inputs.
• Selective attention may involve a binocular
  rivalry when each eye receives different input.
• Any sources of input that cannot be integrated
  into a single consciously perceive whole tend to
  compete against each other and require selective
  attention.
• Prefrontal cortex guides what is selected.

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Brain basis of attention
neurons responses to threat and neutral faces

• What determines what object the attentional
  system selects?
• Attention cannot be understood without emotion,
  motivation, and prominence.
• Salience maps that are sensitive to prominent
  events exists in many regions.
• In visual system salience may be encoded down to
  V1 area.
• Biologically significant stimuli draw attention.
• Face recognition neurons respond very actively to
  threat faces.

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Brain basis of attention

• Multiple salience maps has been proposed.
• For example
• Posterior parietal cortex controls a visual
  salience maps, while
• Prefrontal cortex has a map for top-down, task
  relevant information and
• Superior colliculus has attentional guidance
  system to control the focus of attention

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Brain basis of attention

• Human may learn to go against a cue or usual
  response.
• For instance he/she may learn not to respond to
  the telephone ring.
• This involves
• executive attention control as in the
  experiment shown on figure.
• First the subject learns to follow the cue like
  in the flanker test,
• Then the rule changes and the expected target
  appears on the opposite site of the cue.

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Brain basis of attention

• The executive attention involve more prefrontal
  and parietal regions.
• Figure to the right shows a similar activation
  for executive attention in Stroop color-naming
  task

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Brain basis of attention

• Brain areas for selective attention.
• Voluntary eye movement is controlled by frontal
  eye field.
• The anterior cingulate plays a major role in
  detecting and resolving conflicting information.
• Right frontal and parietal regions are control
  spatial guidance to attentional target.
• The pulvinar nuclei of the thalamus and superior
  colliculus provide eye movement control.

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Brain basis of attention

• Most visible selective attention is orienting
  ones sensory receptors towards the object
  looking, sniffing, listening, or touching.
• Visual selective attention overlaps brain region
  for eye movement control.

• Eye movements are highly selectional skills.
• They are controlled by both cortical and
  subcortical parts
• The cortical control include frontal and parietal
  eye fields guided by explicit goals under control
  of dorsolateral-prefrontal cortex DL-PFC
• Subcortical control of eye movement is by
  superior colliculus SC

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Brain basis of attention

• In the past, tracking eye movements required
  sizable lab equipment.
• Nowadays this has been reduced to a backpack
  size, so visual attention can be studied in a
  natural environment.
• All the brain subcortical regions that control
  eye movement contain visuospatial maps.
• These maps are synchronized with each other to
  focus attention on a selected visual event.
• There is growing evidence that the maps are
  synchronized with gamma-band rhythms (about 40
  Hz)

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Brain basis of attention

• Maintaining attention against distraction
  requires a significant effort
• E.g. trying to study when your roommate plays a
  loud music
• Shutting out the distracting activity may
  overload our processing capability.
• Such shutting out is easier when you do more
  routine tasks (e.g. listen to your favorite
  music).
• Thus mental effort comes from struggle between
  voluntary (goal driven) and automatic attention.

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Brain basis of conscious experience

• Conscious cognition is close to attention,
  however not identical.
• Useful experimental methods to study
  consciousness include
• Inattentional blindness
• Visual backward masking
• Change blindness
• Attentional blink
• Automaticity due to practice
• Remembering vs knowing
• Conscious vs unconscious word priming
• You may be aware (conscious) of reading this
  text but you may not be conscious of the touch of
  your chair, gravitational forces, background
  conversation, your feelings for a friend, or your
  major life goals.

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Brain basis of conscious experience

• Consciousness is not just the passive experience
  of sensory inputs, but the active involvement and
  perception. Self"-related phenomena such as
  preference, social cognition, self-recognition,
  self-modeling, reflection, and planning all may
  be central to an understanding of consciousness.

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Brain basis of conscious experience

• Words may be unconsciously present in your memory
  before you bring in a specific meaning.
• When you read that someone likes to fly, you do
  not bring to your conscious mind other meanings
  of this word.
• They are still in your memory, so what mechanism
  brought the correct meaning to your mind?
• Research supports that those other meanings were
  active unconsciously for a few tenth of a second
  before your mind decided on the right one.

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Brain basis of conscious experience

• Experiments compared seen and unseen, novel vs
  habitual skills, conscious and unconscious
  processing of the ambiguous stimuli.
• Binocular rivalry is often used to study
  conscious vision by delivering two different
  images to two the two eyes.
• In the example figure the middle picture
  disappears due to binocular rivalry

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Brain basis of conscious experience

• As long as two different inputs cannot be
  integrated they will rival.
• There are many kinds of binocular rivalry
• Two different orientations will compete against
  each other
• Different color patches will rival
• If objects in different eyes are moving in
  different directions, they will rival
• Pictures of faces and objects will rival.

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Brain basis of conscious experience

• The two neighboring inputs can be fused into a
  single object.
• You will see a 3D effect after fusion.
• Count how many womans faces you can see after
  fusion?

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Brain basis of conscious experience

• Can you see sphinx and pyramids?

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Brain basis of conscious experience

• Binocular rivalry allows comparison between
  conscious and unconscious picture.
• Subject is wearing prism goggles so each eye
  receives different pictures.
• These two inputs cannot be fused into a single
  object.
• Unconscious stimulus is still processed by the
  visual vortex but subjects reports only the
  conscious one.

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Brain basis of conscious experience

• Visual backward masking.
• Subjects are presented two faces one after
  another.
• The smiling face is shown only for 20 msec.
• The brain identifies both stimuli but subject is
  not aware of the smiling face.

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Brain basis of conscious experience

• Inattentional blindness.
• Subjects are asked to watch the basketball being
  tossed between team players (white-shirted).
• Most subjects are not aware of the gorilla
  passing by even if it stands and waves to camera.
• Ball throwing movie

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Brain basis of conscious experience

• Unconscious processes has been studied in several
  categories
• Implicit memory
• Amnesic patient were given a word like
  assassin, and could not recall it later.
  However given a word fragment like -ss-ss they
  can retrieve the correct word
• Implicit learning
• Children do not learn the language by grammatical
  rules but by repetitions. The rules are inferred
  subconsciously.
• Implicit perception
• My occur when perceptual cortex is damaged
  (damage to V1), parietal neglect (inability to
  perceive half of the visual space), face
  blindness etc.
• Automacity
• Highly practiced and predictable skills become
  unconscious. Automatic process consumes no
  attentional resources, nor does it effect ongoing
  cognitive process or leave trace in the memory.
• Unconscious cognition
• Examples are priming or unconscious period
  between thinking of question and realization of
  the answer.

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Brain basis of conscious experience

• Logothetis (2002) studied visual perception in
  macaque monkeys.
• They observed brain activities in case of visual
  rivalry.

• 20 of neurons in early visual regions (V1, V2,
  V4) and about 40 in areas MT and MTS responded
  to the dominant reportable stimuli and similar
  to non-reportable stimuli.
• However, in object regions of the brain (areas IT
  and STS) 90 of neurons fired in response to
  reported stimuli and none for non-reportable.

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Brain basis of conscious experience
Comparison of evoked potentials in conscious and
backward masked printed words. Conscious words
maintain activities for longer period of time
after presentation and engage more brain regions.

• Many researchers confirmed that conscious context
  mobilize frontal and parietal brain regions.
• Dehaene (2001) used visual backward masking
  comparing brain activities to a conscious words
  to the same words when they were masked by a
  pattern.
• They used fMRI and evoked potentials to localize
  hot spots in the brain

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Brain basis of conscious experience

• Results that conscious context activate larger
  regions in brain were confirmed by observing
  responses of individual neurons, through
  electrodes placed in different brain areas.
• Another example is conscious and unconscious pain
  in which unconscious pain barely reached cortex
  and conscious one engaged large brain areas.
• While learning new tasks (like walking or simple
  games) children are very conscious of actions,
  but after they master it and action becomes more
  automatic it becomes less conscious.
• In an experiment with metronome subjects were
  supposed to repeat its rhythm by tapping.
• When rhythm was regular it was quickly learned
  and automated with no activation of executive
  control and dorsolateral regions.
• When rhythm was distorted randomly within 3 a
  little more brain activities were observed, and
  when it was distorted by 20 a lot.

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Brain basis of conscious experience
Brain synchrony

• Technology allows to observe interactivity of the
  brain regions.
• Consider a conscious event like pointing to a
  cup. It involves activation of
• Visual cortex to detect the cup, identify its
  size, location, shape and retrieve the object
  memory
• Prefrontal, premotor and motor regions to decide
  to point into a cup, generate a plan to move a
  finger, and move appropriate muscles.
• A decision to execute the action from prefrontal
  cortex, parietal spatial maps, and triggering the
  motor action.
• Sensory feedback to check whether the action has
  been accomplished.
• Each of these steps requires millions of neurons
  firing in a coordination.
• Gamma activity (40 Hz) is involved in feature
  binding, theta activity is involved in episodic
  retrieval from long-term memory, with rapid
  moments of synchrony between various brain
  regions.

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Summary
Attention and conscious perception selection and
integration.

• Selective attention seem to be focusing of brain
  resources on the visual cortex. In the opposite
  flow a visual object mobilize cortical regions.
• There is a rapid cycle between attentional
  selection and conscious integration with
  simultaneous activation of parietal and frontal
  regions.

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Summary

• A neural net architecture for selective attention
  and visual consciousness.
• Visual information flows from V1 to areas V2-V4,
  an d finally IT where objects are detected.
• Each area has its inhibitory neurons to sharpen
  differences at that level.
• Posterior parietal neurons (PP) bias visual
  neurons that detect the object in that spatial
  location.
• Prefrontal neurons in area 46 are involved in
  voluntary attentional selection.

Attention and conscious flows.