PSYC10003 Lecture Notes - Lecture 12: Saccade, Inattentional Blindness, Change Blindness
6 Jun 2018
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PSYC10003 – MIND, BRAIN, & BEHAVIOUR 1
BEHAVIOURAL NEUROSCIENCE
Lecture 12 (Week 4 . 3): Neural Correlates of Attention & Consciousness
Attention: set of processes used by brain to select stimuli & actions that’re currently relevant to control
ongoing behaviour, & inhibiting stimuli & actions that’re currently irrelevant
• Damage to primary visual cortex → blindness in visual field region represented
by affected area. Can still respond in simple ways to visual stimuli (blindsight:
eg making hand/eye movements to visual targets, & discriminating between
different visual stimuli at above-chance levels). Lack conscious awareness
• Spatial neglect. Unaware of impairment. Most common after damage
to R hemi of parietal cortex
• Still considerable unconscious processing of neglected info
• 90% of visual info from retina goes to lateral genicular nuclus
(thalamus), then to the primary visual cortex (geniculostriate
pathway). Other 10% bypasses LGN, & instead go to superior
colliculus & pulvinars nucleus of the thalamus, then other visual areas
of the cortex. Lack of direct input to V1 → no conscious visual
experience. Alternative pathway →some unconscious visual perception
• Key aspects of attention:
• Selectivity: restricts processing to just those occupying a particular region of space / at a
particular time. Voluntary allocation of attention can enhance perception of stimuli in a selected
region of space, despite the receptors (retina) remaining fixed (potentially elsewhere)
• Limited capacity: only 3-4 separate objects at a time
• Vigilance (sustained attention): period of time we can effectively sustain attention
• Perceptual set (expectations): involved in their establishment & maintenance. Tend to focus
processing resources on inputs & behaviours relevant to the current environment & task demands
• Switching: from one task / environment to another
• Attention enhances the rate of info processing at attended relative to unattended locations
• Inattentional blindness: insensitive to salient stimulus events when attention is engaged elsewhere
• Modulates conscious perceptual experience
• Change blindness: fail to detect substantial changes in visual objects & scenes across saccades, eye
blinks, movie cuts, or shift of attention (visual transients). Suggests a that there’s a limit to the
amount of visual info that can be encoded, maintained, & compared across successive glimpses
• Extracellular microelectrode recordings show single neurons in parietal cortex modulate their firing
rate according to the attentional demands of a visual task
find more resources at oneclass.com
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Document Summary
Can still respond in simple ways to visual stimuli (blindsight: eg making hand/eye movements to visual targets, & discriminating between different visual stimuli at above-chance levels). Most common after damage to r hemi of parietal cortex: still considerable unconscious processing of neglected info, 90% of visual info from retina goes to lateral genicular nuclus (thalamus), then to the primary visual cortex (geniculostriate pathway). Other 10% bypasses lgn, & instead go to superior colliculus & pulvinars nucleus of the thalamus, then other visual areas of the cortex. Lack of direct input to v1 no conscious visual experience. Alternative pathway some unconscious visual perception: key aspects of attention, selectivity: restricts processing to just those occupying a particular region of space / at a particular time.
