Ch. 22 : Attention & Consciousness

Consciousness vs. Attention

• how we select info on which to act & how we select diff behaviours

  • as sensory info & possible behaviours become more complex/varied → determination on which to select becomes more challenging

Attention = top-down & takes time to focus on a part of the sensory world

• narrowing of awareness to a particular part of the sensory environ

• parietal lobe is involved in ability to shift attention

• an automatic process

• conscious operations require attention

Consciousness = provides a summary of all info relevant to the situation

• awareness / awareness of awareness

• includes things we’re paying attention to & not paying attention to

ex. ducking when a ball almost hits you, when you weren’t paying attention to it

Automatic Processes vs. Conscious operations : reliance on attention

Automatic processes = performed w little focused attention & occur unconsciously

• doesn’t require attention, but we can use it

• innate or results from training (ex. had to learn how to walk)

• bottom-up, THUS driven by sensory input

  • environ stimuli are sensed by body → body automatically reacts to it

Conscious operations = require focused attention

• requires attention

• top-down, THUS require cognitive input & control (ex. how you approach writing is based on experience)

→ due to the diff types of processing & input (cognitive vs. sensory), its likely that automatic & conscious processes rely on DIFF brain circuitry - possibly including the circuits related to consciousness

• THUS, 2 diff areas should light up when imaging the diff. processes

Visual Processing Tasks (Visual Search)

= have to identify what’s diff & measure the time taken

• right-side tasks are more difficult

• shows that some visual search tasks are/aren’t automatic

→ visual searches requiring you to look for multiple features (ex. a T and bolded) take longer = feature search

→ visual searches that are simple take less time (ex. looking for a line)

→ visual searches where we add more meaning to an image (ex. seeing these as trees and dining the non tree) are harder & use top-down (THUS require cognitive input & control)

upper left image: serial search, automatic bc looking for simple vertical line

upper right image: harder bc we add meaning to the shapes (trees), thus uses top-down bc we’re relating them to experiences…

bottom left: takes longer bc its combining multiple features ( T and bold)

bottom right image: harder bc were trying to give it meaning, as wer’re looking for words amongst the letters

Research Into Attention: Types of Visual Searches

→ serial & feature search require DIFF amounts of attention

• feature search requires MORE attention

• certain types of visual search are automatic: addition of a vertical line, or use of bold type

• Serial search = slower searches bc they require the combination of multiple features

  • top-down

• Feature Search = strategy for scanning the environ for an object w a specific combination of features

  • bottom-up process:

1. object visually perched in V1 → broken down into features to be processed serially by higher visual areas

2. features of the object in the mental spotlight are recombined (possibly thru reentry processes)

note: areas outside of V1 or V2 should respond differently to a stimulus, depending on whether attention is focused on the object

Treisman’s Model of Feature Search

main idea:

• only what’s in your attention spotlight enters object file in memory

  • if spotlight DOESNT have features we’re looking for → shift visual field

  • once features are matched → safe object file in memory

proposed process:

1. V1 encodes basic properties (feature maps)

   1. from retina to v1 (early vision)

2. attention spotlight = when looking at one spot of visual field

   1. can still see everything else

   2. as we shift attention in visual field → see new feature maps

3. whatever in attention spotlight is sent to object file (compared to memory to see if features match)

4. object file is sent to memory to be identified & stored in memory

Study to Determine what a Feature is

study: found that participants were able to identify sad faces MORE rapidly than happy faces

• this occurred regardless of the whether sad face was right-side up, upside-down or an abstract representation

why: its NOT bc of the sad faces lips having extra lines, its bc f the emotion associated with sad

→ THUS, feature DOESNT need to be physical representations, it can be an abstract idea like emotion represented

Neuropsychological Evidence of Attention: Study

note: experiments testing the effects of the focus of attention must use the same stimulus in all conditions

ex. can only use happy or sad face, NOT both

study: varied the location of a stimulus & identified diff responses in higher visual areas (V4, TE) that depended on where the stimulus was presented & what the monkey was trained to attend to

findings:

• multiple visual attention systems: one selecting stimuli & the other selecting and directing movements

• priority maps encode stimulus location in terms of behavioural significance

  • maps are found in frontal eye field, lateral intraparietal area & superior colliculus

Demonstrating Selective Attention: Study

study: monkeys were trained to release a bar when a stimulus is presented in a certain location - earned to ignore stimuli in all other locations

results:

• before training selective attention: neurons in V4 (visual area for colour) responded to stimuli in all locations

• after training: V4 neurons ONLY responded when the visual stimuli was in the rewarded location → showing selective attention

→ THUS, a neuron can learn to respond selectively to info in its receptive field

• something before V4 determines whether the info will be perceived

• THUS, attention intercepts perception

Divided Attention & Selective Attention

note: most research says we’re NOT good at multitasking (divided attention)

→ mental capacity is limited, thus dividing attention b/w multiple tasks can divide that limited resource & cause all tasks to be performed worse

• especially when the tasks require the SAME resources - thus, divided attention is easier is the tasks use DIFF resources

• routine tasks can be performed w ease while doing another task - bc they become more automatic w use

→ we can shift our attention to be SELECTIVE

• shown by V4 (colour/form) cells being selective abt what they respond to

• cells are normally responsive to a combination of orientation & colour, BUT will respond to lines of somewhat diff orientation

ex. when animals discriminate b/w lines of similar orientation: see a decrease in performance accuracy, indicating the task is harder + activity in V4 cells increases to makes the cells more selective abt what they respond to

ex. cells in the pulvinar project, throughout the cortex, may help direct the attention spotlight

Study of Effort & Attention

found that:

• cells in V4 only respond to certain lines, but when they go thru discrimination training they become MORE SELECTIVE abt what lines they’ll respond to (trying to make the task easier)

  • when tasks/discriminaiton becomes more difficult, the cells become more selective

Parallel Processing of Sensory Input

parallel processing of sensory input

• with one object in the attention spotlight: visual system can bind all the properties together

• with multiple objects in the attention spotlight: cells in areas TE process diff objects in parallel (at same time) to differentiate

→ thus area TE processes what these objects are by identifying differences bw them

• attention must be divided across sensory modalitiesfor multi-sensory stimuli → need divided attention to connect senses

→ when attention is directed at one sense: activity increases in the related cortical areas

ex. focusing on the image of a movie → visual areas more active

ex. focusing on the words/sounds → auditory areas more active

→ when attention is divided b/w 2 senses: no change in the individual sensory areas, instead theres an increase in the Left Dorsolateral prefrontal cortex

• Left Dorsolateral prefrontal cortex (DLPFC) =F allows us to multitasks when 2 senses/modalities are different (BIOMODAL): by filling in the gap to make multitasking more efficient b/w the 2 diff tasks

  • ONLY occurs when the 2 tasks use diff resources (ex. auditory & visual tasks at same time)

thus, divided attention recruits DLPFC when bimodal

Functional Imaging & Attention

study: 2 tasks each using the same stimuli, but different attentional demands

• attending to the moving light stimulus resulted in increased activity in the posterior parietal cortex

  • if light was in L-visual field: only the R-parietal cortex was active

  • if light was in the R-visual field: bilateral parietal cortex was active

→ shows: R-parietal lobe is the main one for paying attention & can fill in for damaged L-partial cortex

• each visual field has a diff focus of activation in the R-parietal lobe

note: this is related to contralateral neglect w damage to R-hemisphere

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study: has a selective-attention condition & a divided-attention condition

• diff types of attention (selective/divided) recruited diff brain areas

• attentional tasks activate the anterior cingulate (frontal lobe for decision making), prefrontal cortex, & sensory areas related to the task

ex. if it was an auditory task → activates auditory areas

Shifting Attention

main idea: shifting attention uses the parietal lobe, bc movements of attention is involved

• shifting attention is tested covertly, meaning w/o eye movement

→ shifting attention uses diff. brain areas than fixed attention

• fixed attention: NO diff b/w hemis parietal lobe activity, bc you’re ignoring activity of the sides

• shifting attention: diff b/w hemis parietal lobe activity

  • L-hemis parietal is ONLY active for shifting on R-visual field

  • R-hemis parietal is active for shifting on both visual fields

Networks of Attention

• attentional system is distinct from the sensory networks that process info (ex. visual movement processing vs. processing movement)

• attention ISNT a single process, its a connection of areas throughout the brain

  • brain regions form 3 diff attention networks:

1. Altering network : norepinephrine modulates

• structures: locus coeruleus, frontal & parietal cortex

2. Orienting network : acetylcholine modulates

• structures: superior parietal, temporal parietal junction, frontal eye fields, superior colliculus, pulvinar

3. Executive network : dopamine modulates

• structures: anterior cingulate, anterior ínsula, basal ganglia

→ each network uses a diff neurotransmitter

Networks of Attention: Alerting Network

Alerting network = ascending reticular activating system from the midbrain, that maintains alertness

• changes w age → becomes harder to suppress, leading to sleep disorders

• assoc w ADHD

• altering network activity SUPRESSES processing in other cerebral networks - thus, when activated it tells other attention networks to stop

→ modulator: norepinephrine

• norepinephrine agonist: increased altering network

• norepinephrine antagonist = decreased altering network, thus respond less to alerting stimuli

How it works:

1. noradrenergic neurons project from the locus coeruleus to the forebrain (frontal & prefrontal)

2. alerts the prefrontal & posterior parietal cortex to rapidly process & respond to stimuli

3. activity suppresses processing in other cerebral networks

Networks of Attention: Orienting Network

• prioritizes ONE sensory modality or a particular location in space

ex. only vision (sense) or only what’s occurring in a location

→ modulator: cholinergic neurons that produce acetylcholine

→ has 2 networks: ideally ACTIVATED @ SAME time

• Dorsal orienting network = directs attention twd a specific object in a top-down process

  • ex. look for Waldo, then break down his features

  • involves the frontal eye fields & intraparietal sulcus

  • strongly R-lateralized - more activity in R-hemis

• Ventral Orienting network = synchronizes activity w bottom-up incoming sensory info

  • ex. looks for features until they have all of them

  • involves the temporoparietal junction (similar to ventral visual stream), ventral frontal cortex & pulvinar (attention & decision making)

→ associated disorders:

• autism - hyperfrouc on everything in one location/sense

• PTSD - difficulty disengaging from fearful stimuli

• neglect - over-orienting on one side (contralateral neglect)

Networks of Attention: Executive Networks

• develop as we age, maturing around 3-4yrs old - thus at that age children can control their emotions

• can override the alerting or orienting attention networks

  • talks to orienting, altering networks & others

• w increased executive network = MORE control of attention

• dopamine modulates

→ 2 executive networks work via top-down influences:

• activity in areas WITHIN a network is highly correlated - areas in the 2 networks are all active if one is active

• NO correlation b/w activity in the 2 networks - the 2 networks can operate at diff times, thus can be independent

1. Dorsolateral-prefrontal cortex-parietal network = active at the BEGINNING of a task

ex. active at start of driving

~ex. moment-moment task

2. Anterior Cingulate/medial frontal-anterior ínsula network = remains active THROUGHOUT the task (so we can continue a task)

ex. takes over after 1-2 min driving & continues for the rest

~ex. task maintenance

→ Associated disorders:

• anxiety

• depression

• OCD - stuck in cingulate network

• personality disorders

• schizophrenia - lack of inhibition

• substance abuse

Attention Networks & Self-control

→ controlling cognition & emotions is a form of self-control

• have better self-control when theres MORE control of attention networks

• self-control of cognition & emotions is associated w activity in the lateral prefrontal & cingulate regions:

  • stress changes the structure & gene expression patterns of the prefrontal cortex → deficits in cognitive control of emotion

bc: part of the prefrontal cortex’s job is to inhibit areas that increase emotional rxn, thus when damaged it cant inhibit → increase emotional rxn

ex. psych stress impairs the performance of medical students on attentional tasks - by decreasing activity in the dorsolateral prefrontal cortex, anterior cingulate, premotor & posterior parietal cortex

• stress DECREASES activity of the executive control network → less control of attention

Attention Networks: Associated Disorders

→ w/o the control of the executive networks → alerting network goes off all the time

Mechanisms of Attention: Hypothesis of Directing Attention

hypothesis: that the attention system directs attention by inducing synchrony b/w neurons (spatial summation) that assess the sensory signal

• thus, synchronizing what diff parts of the brain are doing

• adjusts timing of action potentials so the input from 2 neurons arrive at the same time & location → summed → increasing chance of an action potential in the postsynaptic cell (spatial summation)

• during a task requiring attention: increased activity in the dorsal executive attention network & decrease in the default network (baseline brain activity)

→ attention increases synchrony in the brain: neurons within a network, even in diff areas, fire at the SAME time

• says we’re more likely to reach threshold w summation when attending to something (giving attention), via synchrony of neurons

Inattention

Inattention blindness = person fails to notice something while they’re performs another task

• when distracted by a counting task, 70% of participants failed to notice a gorilla suit

Change blindness = ppl routinely fail to notice changes in the environ if they aren’t expecting them

Attentional blink = attending to 1 stimulus prevents the subject from being aware of a 2nd stimulus

• using orienting network (prioritizes one sense/location)

→ imaging studies show these unattended items are detected by the sensory systems, BUT are filtered out BEFORE conscious awareness

Sensory Neglect

ex pts w damage to the R-temporoparietal junction DONT attend to the L-side of space around them

Paying attention to objects:

→ objects in the R-visual field can be attended to by the left or R-parietal lobe

• both, bc the R-parietal lobe is a backup for the L-parietal

→ objects in the L-visual field are ONLY attended to by the R-parietal lobe

→ damage to the frontal lobes (BA 6) results in contralateral neglect ONLY for objects close enough to be grasped

• which hemisphere depends on if damage is to the L or R frontal lobe

Treatment of sensory neglect:

• moving head or using prism to shift objects from the L-visual field to the R-visual field for a few min a day → signif greater ability to attend to objects in the L-visual field

  • reminds brain to scan area

Consciousness

Consciousness = level of responsiveness of the mind to impressions made by the senses - thus, its how much we respond to incoming senses

• changes over time:

  • rxns to stimuli vary overtime

  • young kids & those w dementia experience a diff level of consciousness

  • levels of consciousness vary over the day w the transition from sleep → wakefulness (sleep =/ unconscious, its an altered state of consciousness)

  • can change levels w drugs & hypnosis

• reflexive responses to stimuli ARENT considered indications of consciousness

• conscious awareness of a movement might only occur AFTER the movement is complete

  • thus, we can do sensory reflexes and then become aware w didi it

• ventral stream (ability to identify) is considered a part of conciousness

• dorsal stream (action) ISNT considered a part of consciousness

Consciousness: Dissociating Behaviour & Awareness

study: subjects had to move their hands & grasp the lit rod as fast as possible

• some trials had the list rod changing b/w targets → subject had to correct their aim to grab new lit stick

findings:

• most participants were already holding the new lit rod BEFORE they could consciously say that it switched (weren’t aware, but still did it)

→ said this shows its possible to dissociate behaviour & conscious awareness

→ say this supports the ventral stream being part of consciousness, whereas the action (dorsal stream) was unconscious

Conciousness: Integrated Information Theory

Integrated Information Theory = attempts to explain consciousness

says consciousness:

• exists

• is structured & composed of multiple distinctions b/w the phenomena we observe

• composed of specific info & and that each experience is DISTINCT from e/o

  • even if u experience the same info in 2 diff days, still distinct

• unified & CANT be broken into multiple subparts: its ALL one thing

• made of individual experiences that are separated from other conscious experiences by cause-and-effect relationships

  • we learn & build on past experiences (related to classical & operant conditioning)

→ can apply this theory to explain diff forms of consciousness in clinical pts

Conciousness: Neural basis

neural basis: consciousness requires the interaction of sensory areas, memory & other systems like emotion & executive fxn - these are connected w networks

• consciousness includes 4 processes: arousal, perception, attention, & working memory that use binding to unify

  • binding synchronizes the activity in relevant networks for a short period (not just the cells in one network syncing up)

• rapid synchronization across widely separated brain areas is possible & regularly observed

support: studies of perceiving & responding to faces show patterns of synchronous activity → asynchronous → synchronous activity

• showing there seems to be a purpose for both synchronous (cells in diff areas firing at same rate) & asynchronous

• shows we’re more consciously aware & pay attention to things perceived as faces

  • thus certain types of stimuli draw more attention

  • synchrony & asynchrony are both important for perceiving faces

Conciousness: Neural basis - Shadow of a Perception study

study: tracked neural synchrony in brains perceiving a face vs. those not perceiving a face

findings:

• brain w face perceived: synchronous activity over L-hemis → asynchronous in both hemis → synchrony with motor response to pressing button

• brain w/o face perceived: asynchronous activity → brief synchronous activity for motor response to press button to say they didn’t perceive a face

shows:

• we’re more consciously aware & pay attention to things perceived as faces

  • thus certain types of stimuli draw more attention

  • synchrony & asynchrony are both important for perceiving faces

Conciousness: Cerebral Substrates

• we dont know the essential neural regions for consciousness

  • imaging studies study consciousness by contrasting activity when subject in unconscious (coma, vegetative state) with conscious activity

→ dorsolateral prefrontal cortex, medial frontal cortex, posterior parietal cortex, & posterior cingulate cortex are all INACTIVE when unconscious

• these can be active when you’re asleep

  • some parts of the brain increase in activity when asleep

→ a network of frontoparietal areas is correlated during a quiet, resting, conscious state

Clinical studies of Consciousness

• pts in a coma or vegetive state (unconscious) produce brain activity in response to verbal commands

  • fMRI can show diff brain activity from asking questions, thus they can hear

• studies suggest theres a bilateral region of the parietal lobe necessary for consciousness

  • theres NO necessary area in the frontal lobe for consciousness

• proposed that the Claustrum is the brain region CRITICAL in binding together info, since is receives connections from nearly the entire cortex

  

Emotion & Conciousness

→ emotions are related to consciousness, but you can have one w/o the other

• overlapping brain regions associated with consciousness & self-awareness:

  • medial frontal cortex

  • posterior cingulate cortex

• consciousness may NOT be necessary to experience emotions:

  • non-conscious emotions can be demonstrated by experiments of fear conditioning

Nonconscious Processing

→ blindsight (awareness w/o perception), dorsal-stream processing & other experimental evidence suggests cognitive activity CAN occur on the nonconscious level

Nonconscious Processing = processing sensory info w/o consciousness

• when asked to explain their behaviours, ppl often dont recognize & report the actual factors that influenced their behaviours

ex. “idk” → then come up w a reason

• sensory systems take in a lot of info to influence decisions, but we are only consciously aware of a small amount of that info:

  • Automatic process: use system 1 to generate rapid, NONconscious responses to stimuli

    • ex. pupils constricting to light, raising voice in loud environ

  • Conscious processes: use system 2 to produce slower, controlled responses based on relevant knowledge & experience

    • used when learning something new, then we can use automatic

Neuroeconomics

Neuroeconomics = studies how the brain makes decisions

• what influences our decisions?

→ influences from neuroscience, cogntive psych, social psych & behavioural economics

→ current research is focus on its application to health psychology

• to better understand how ppl make decisions abt health & wellness behaviours -. then we can create better treatment plans for their thinking process