Attention Flashcards
(21 cards)
1
Q
what is attention?
A
- the process in which the mind selects from among the various sensory stimuli which ones it will process at any given moment
- James 1890 - withdrawal from somethings to deal with others
2
Q
what is the functional significance of attention?
A
- allows only some information to enter consciousness we maintain an incomplete picture of the world
- hoffman - simulation study from evolutionary stance it’s disadvantageous for the mind to represent the world as it is
- successful organisms process only a subset of stimuli and create representations of these which are salient from the POV of survival & reproduction
3
Q
what is attention for?
A
- help you find things
- help you notice things that are important
- help you ignore things that aren’t important
- influenced by context
- salience
4
Q
what are the types of attention?
A
- focused, selective, sustained, spatial, goal-centred, object-centred, involuntary attention, divided
5
Q
how do we measure selective attention?
A
- auditory
- dichotic listening tasks
- active/passive tasks
- cocktail party phenomenon
- visual
- spatial selective attention
- visual search paradigm (w/ distractors)
- outcome measures
- behavioural
- chronometric analysis
- strength of EEG signals
- EEG paired with spatial techs e.g., PET
6
Q
how do you visually study selective attention?
A
- covert (no head/body movement)
- the participant is instructed to ignore the left stimuli and attend to the right stimuli
- brain response is compared for the same stimuli depending whether P was attending to L or ignoring it
7
Q
how do you auditorily study selective attention?
A
- dichotic listening task
- attend and unattend conditions
- passive and active conditions
- pay attention to sounds or watch a video with sound off
^ attention is the only thing being changed
^ nature of task is different & arousal might be different
- pay attention to sounds or watch a video with sound off
8
Q
what are the effects on the brain?
A
- leads to higher activation of those neurons responding to the stimulus
- auditory & visual cortex activity
- subcortical activity
- measured in different ways
- non-invasive (EEG, EMG, fMRI)
- invasive single-cell/array electrode recordings
- seems to reconfigure receptive fields in the sensory areas
9
Q
what is the evidence that shows attention enhancing brain responses?
A
- Hillyard et al.
- auditory cortex ERP
- amplitude in N1 is enhanced when attending to a stimulus compared to ignoring a stimulus
- Van Voorhis & Hillyard 1977
- visual cortex P1 in amplitude is larger when visual stimuli appears at an attended location than when attention is focused elsewhere
10
Q
what is the cocktail party effect?
A
- selective auditory attention task e.g., cherry 1953
- how we separate info of interest
- ability to follow one conversation in the presence of many others
- attention filters out BG noise
- more difficult than dichotic listening
- sound is mixed together
- asked to identify e.g.: different messages, locations, speakers
11
Q
what is the evidence that shows that attention modulates activity in the auditory cortex?
A
- Mesgarani & Chang 2012
- mixed sentences to human epilepsy patients
- micro-electrode intracortical recordings from surface of the auditory cortex
- stimulus spectrogram reconstruction from neural responses
- measured neuronal activity & predict what the stimulus was
- stimulus reconstruction in the mixed sound condition depended on which sentence was being attended to
- during the mixed condition, the auditory cortex responded as if the sentence being attended to is being presented alone.
12
Q
what is the evidence that shows that attention modulates activity in the visual cortex?
A
- Hopfinger et al., 2000
- bilateral cued spatial attention task (covert) with fMRI.
- separate the effects of selective attention control and visual sensory signals
- aimed to get separate evidence of the sensory processing structures and voluntary attention control network
- results compared based on whether or not the participant was attending to the location of the target
- instructive cues leads to increased activation in visual cortex of the contralateral hemisphere in anticipation
- this voluntary change in attention focus resulted in selective sensory processing of relevant targets
13
Q
what is the selective attention network?
A
- sensory signals enter cortex via thalamus
- the meaning and salience of signals is represented in PFC
- PFC generates signals for where to focus attention - it targets two places
- attentional control network
- targets sensory cortices -> response enhancements - thalamus
- attentional gating mechanism controlled by PFC
13
Q
what is the attentional modulation of the thalamus?
A
- PFC controls which sensory inputs make it to cortex via TRN and thalamus
- thalamus = subcortical entry gate to cortex
- thalamic reticular nucleus (TRN) = thin layer of inhibitory neurons surrounding thalamus
- PFC switches on individual cells in TRN
- activated TRN cells then suppress signals in thalamus
14
Q
what is the evidence for visual attention control?
A
- selective visual attention [goal/task]
- active when attention is directed to a spatial location in expectation of a task-relevant stimulus
- in this situation before the target is delivered attention also activates visual cortex
- reflexive attention [salience/novelty]
- directs attention to stimuli with high salience
- suppressed during selective attention tasks
15
Q
what is the evidence for auditory selective attention control?
A
- Hill & Miller 2010
- auditory attention control/selection during cocktail party effect
- fMRI: Examined cued attentional responses for both pitch and location trials.
- RESULTS: left-hemispheric fronto-parietal network (FPN) controls attention:
- Left inferior frontal gyrus (IFG; pitch-cue)
- Left superior parietal lobule (SPL; location cue)
- Left intraparietal sulcus (IPS; both- integrative function/ prioritisation)
16
Q
what is the link between attention and neural plasticity?
A
- In adults, attention leads to plastic changes in the cortex:
- Stimulus is in attentional focus
- PFC activates nucleus basalis (NB)
- NB releases acetylcholine (ACH; excitatory neurotransmitter)
- ACh targets cortical neurons representing the stimulus.
- The connections of these neurons are strengthened via LTP (Hebbian learning)
17
Q
what is the role of the superior colliculus in attention?
A
- The SC/ Tectum= highly-developed neural processor;
- makes sensory discrimination and rapid decisions for motor actions necessary for survival and reproduction.
18
Q
what are the structures of the superior colliculus?
A
- SC integrates information from the senses and cortex and transforms this into orienting responses.
- Upper layers: receive input from retina and visual cortex, respond to visual stimuli
- Intermediate & lower layers:
- Input from all modalities (e.g., auditory pathway & cortex) and from most of the brain
- This includes information about the salience and task relevance of the stimulus
- Lower layers: motoneurons that direct eye saccades and other orienting movements.
19
Q
what is the retinotopic map in superior colliculus?
A
- Each SC layer is a topographic map of space in retinocentric coordinates.
- An object /event with a spatial location activates neurons in a specific location on the map.
- Activation of motor neurons in a particular location will initiate a saccade which shifts the gaze and attention onto that location.
20
Q
what is the role of competition in the control of attention?
A
- Fierce competition on SC space map via inhibition: only one location wins
- The highest priority stimulus suppresses activity at all other locations.
- During selective attention task, cortical networks and SC in “agreement” on the winning stimulus – the attended stimulus is tagged by 40-Hz oscillations (gamma band) in SC, thalamus, and cortex.
- SC can override cortex and shift attentional focus on its own.
