NEUR2020: W5 Attention

Attention

attention

processes that enable a person to recruit resources for processing selected aspects of the incoming sensory information more fully than non-selected aspects; includes allocating resources to relevant aspects of the environment and inhibiting irrelevant information

Reticular Activating System (RAS)

network of neurons in the brainstem responsible for regulating arousal, sleep-wake transitions, and consciousness; attention is not alertness and arousal

capacity

important component of attention; the amount of perceptual resources available for a task/ process; varies with task and individual

selectivity

important component of attention; at any given moment the fixed perceptual resources can be allocated to different subsets of information in a flexible way; attention is selective

the royal exchange effect/ cocktail party effect

ability to focus on one specific auditory input while filtering out others in a noisy environment, such as a crowded party

dichotic listening tasks

cherry (1953); participants simultaneously hear different auditory stimuli presented to each ear. It's used to study how the brain processes auditory information and the role of different brain hemispheres in language and other cognitive function

salience

the quality of being particularly noticeable or important; prominence; own name is special information in the dichotic listening tasks

distractor interference

the distractor (non-target) location is still ‘calculated’ - changes the trajectory of the movement (path of the hand) distractor is not a physical obstacle; slowed reaction times to targets, reduced accuracy to targets, changes to trajectories in movements to targets

searching scenes bit by bit

slowed reactions times to target, reduced accuracy to target; visual spatial attention

overt attention

eye movement to shift attention; selectivity

covert attention

move your attention but not your eyes; selectivity

shifting attention, visual spatial attention

1. disengagement

2. movement/ shifting

3. engagement

diengagement

shifting attention; attention is normally focused on some target; to move, must first disengage from the current target; damage to parietal lobe (right) results in loss of function

movement/ shifting

shifting attention; once disengaged, attention is free to move and must be directed to the new target; damage to the superior colliculus impedes movement

engagement

shifting attention; after reaching the target, attention must be reengaged on the new object; damage to regions in the thalamus compromises function

posner cueing paradigm

neuropsychological task used to study visual attention, particularly how attention shifts across space. Participants are cued to attend to a location, and then a target stimulus appears either at the cued location (valid cue) or at the opposite location (invalid cue).

endogenous cues

symbolic cues, central arrow; attention must be voluntarily pushed from the central cue to the cued location, very limited control; top-down

exogenous cues

attention is drawn to the location of the cue; is usually a flash or movement; cannot be ignored (involuntary), some control; bottom-up

top-down

endogenous, some control

bottom-up

exogenous, not much control

Hermann von Hemlholtz investigated

ability to perceive letters within covertly attended region

spotlight of visual attention

made of the focus, fringe and margin; fringe is 1 deg

zoom lens

attention is loosely likened to a zoom lens on a camera that has variable spatial scope; wider the field, coarser the detail

distributed attention

involves parallel processing and visual pop out; visual processing occurs simultaneously over the whole visual field

focused attention

involves serial processing; visual processing is a series of attentional fixations each covering a different region of the visual field; scan scene bit by bit

serial processing

selecting a bit of the environment at a time; focused attention

inattentional blindness

a phenomenon where individuals fail to notice an unexpected object or event when their attention is focused elsewhere

change blindness

small change in visual display is not detected

middle cerebral artery (MCA) strokes

damage to the right parietal lobe; critical regions are angular and parahippocampal gyri

object neglect

individuals fail to notice or attend to one side of objects, regardless of their location in space

hemispatial neglect

a neurological disorder where individuals experience reduced awareness and attention to one side of space, typically the left, due to damage to the right (parietal lobe) hemisphere of the brain; object vs spatial neglect

visual extinction

preserved detection of single contralesional left-sided stimuli; better detection of left events when allowed to ignore right events/ presented earlier than right events

confrontational testing

failure to report the more contralesional of two simultaneous, bilateral stimuli, with normal reporting of single stimuli on either side

contralesional detection

the identification of stimuli or changes on the side of the body or brain opposite a lesion or damage

ipsilesional detection

the identification of stimuli or changes on the same side of the body or brain as the lesion/ damage

extinction

the patient can detect a single stimulus but fails to report both when presented simultaneously