Attention & Spatial Perception June 6, 2014

1. Attention & Spatial PerceptionJune 6, 2014

2. The Vestibular System

3. Vestibular Information • Balance, spatial orientation – body in space • Relationship w/ motor system • Receptors in inner ear - semicircular canals & otolithic organs

5. Vestibular Information • Semicircular canals - acceleration in vertical, horizontal, diagonal • Spinning, bending • Canals - endolymph & hair cells • Rotation disrupts fluid, bends hairs • Adapts w/ constant motion

6. Vestibular Information • Otolith organs - linear motion in vertical, horizontal • Mvmnt of head in rel. to neck, & in space • Vestibulocochlear nerve – joins auditory info • Synapse at brainstem (near pons/medulla)

7. Vestibular Information • Midbrain – w/ visual info from cranial nerves • Vestibulo-ocular reflex • Cerebellum – coordinate head, eyes, posture • Reticular formation – adjust to new posture • Spinal cord – balance-related reflexes • Cortex – cognitive perception

8. Vestibular Information How could this system be damaged/impaired? Consequences of dysfunction?

9. Spatial Awareness

10. Proprioception • Position, tone of movable parts monitored • Sense that bodies belong to us • Vestibular apparatus, joints/muscles as they move (interoceptors) • Fixation of head – vision, neck muscles, vestibular • Relative position of body parts

11. Everyday examples of reliance on proprioception?

12. Proprioception • Navigate space w/out other senses • Modification of posture, balance • Judge movement based on location in space • “Sobriety test”

13. Deficits in Position Sense “The Disembodied Lady” (Oliver Sacks) • Total proprioceptive loss “I’ve already noticed,’ she added, musingly, that I may “lose” my arms. I think they’re one place, and I find they’re another. This “proprioception” is like the eyes of the body, the way the body sees itself. And if it goes, as it’s gone with me, it’s like the body’s blind. My body can’t “see” itself… “

14. Deficits in Position Sense “The Man Who Fell Out of Bed” (Oliver Sacks) • Asomatognosia – lack of body awareness “‘Look at it!’ he cried, with revulsion on his face…and somehow it seems stuck to me!’ He seized it with both hands, with extraordinary violence, and tried to tear it off his body, and, failing, punched it in an access of rage...”

15. Deficits in Spatial Awareness • Rel. of self to outside world • Difficultly in directing spatial awareness - neglect • Attentional processes • Hemineglect

16. Hemi-neglect Hemi-spatial neglect, hemi-inattention • Attention to, awareness of, one side of space • No sensory deficit • Common for left neglect (right hemisphere damage)

17. Hemi-neglect • Left side of sensory space “nonexistent” • Nothing could be expected to happen there • Half of food, dress half of body “Eyes Right” – Oliver Sacks

18. Hemi-neglect • Frame of reference • Imbalance in directing/disengaging spatial attention • Interaction between parietal, frontal lobes

20. Attention

21. Pay Attention! Perceive only small amount of available stimuli… … select what to attend, ignore the rest How allocate (limited) resources? Relevant? Novel? Consistent?

22. Pay Attention! • Largely unconscious (“grabbed”) • Deliberately directed • Unconsciously monitor unattended stimuli At any time, we see only a bit of the picture

23. Directed Attention • Shift attention • Feature search: sensory info to identify a target • Conjunction search: multiple features, req. conscious attention

24. Directed Attention Complex process… • Feedback to sensory neurons • Memory, vigilance • Decision - what is important • Engagement, disengagement • Association cortex, prefrontal cortex

25. Change Blindness • Neglect to notice changes not attending to • Videos • Simon’s lab - http://www.simonslab.com/ • “Person Swap” video