1. Active Vision Carol Colby Rebecca Berman Cathy Dunn Chris Genovese
Laura Heiser
Eli Merriam
Kae Nakamura
Department of Neuroscience
Center for the Neural Basis of Cognition
University of Pittsburgh
Department of Statistics
Carnegie Mellon University
This is based on Seville07 which was 30 minutes at high speed. Physio + imaging. This set of slides was also used for Istanbul and Columbia and presumably for Barcelona07. For San Diego, I removed the human split brain material.

2. Why does the world stay still when we move our eyes?
Hermann von Helmholtz
Treatise on Physiological Optics,
1866
“Effort of will”

4. Remapping in monkey area LIP and extrastriate visual cortex

5. Remapping in monkey area LIP and extrastriate visual cortex
2) Remapping in split-brain monkeys
Behavior
Physiology

6. Remapping in monkey area LIP and extrastriate visual cortex
2) Remapping in split-brain monkeys
Behavior
Physiology
3) Remapping in human cortex
Parietal cortex
Striate and extrastriate visual cortex

7. LIP memory guided saccade
Stimulus On
Saccade

8. Stimulus appears outside of RF
Saccade moves RF to stimulus location

9. Single step task

10. Spatial updating or remapping
The brain combines visual and corollary discharge signals to create a representation of space that takes our eye movements into account

11. LIP Summary
Area LIP neurons encode attended spatial locations.

12. LIP Summary
Area LIP neurons encode attended spatial locations.
The spatial representation of an attended location is remapped when the eyes move.

13. LIP Summary
Area LIP neurons encode attended spatial locations.
The spatial representation of an attended location is remapped when the eyes move.
Remapping is initiated by a corollary discharge of the eye movement command.

14. LIP Summary
Area LIP neurons encode attended spatial locations.
The spatial representation of an attended location is remapped when the eyes move.
Remapping is initiated by a corollary discharge of the eye movement command.
Remapping produces a representation that is oculocentric: a location is represented in the coordinates of the movement needed to acquire the location.

15. LIP Summary
Area LIP neurons encode attended spatial locations.
The spatial representation of an attended location is remapped when the eyes move.
Remapping is initiated by a corollary discharge of the eye movement command.
Remapping produces a representation that is oculocentric: a location is represented in the coordinates of the movement needed to acquire the location.
Remapping allows humans and monkeys to perform a spatial memory task accurately.

17. LIP
V3A
FEF V3 V2 V1 SC
LGN
Oculomotor System
Retina

18. Stimulus appears outside of RF Saccade moves RF to stimulus location

19. Stimulus alone control
Saccade alone control

20. Single step task

22. Extrastriate Summary
Remapping occurs at early stages of the visual hierarchy.

23. Extrastriate Summary
Remapping occurs at early stages of the visual hierarchy.
Corollary discharge has an impact far back into the system.

24. Extrastriate Summary
Remapping occurs at early stages of the visual hierarchy.
Corollary discharge has an impact far back into the system.
Remapping implies widespread connectivity in which many neurons have rapid access to information well beyond the classical receptive field.

25. Extrastriate Summary
Remapping occurs at early stages of the visual hierarchy.
Corollary discharge has an impact far back into the system.
Remapping implies widespread connectivity in which many neurons have rapid access to information well beyond the classical receptive field.
Vision is an active process of building representations.

26. Remapping in monkey area LIP and extrastriate visual cortex
2) Remapping in split-brain monkeys
Behavior
Physiology
3) Remapping in human cortex
Parietal cortex
Striate and extrastriate visual cortex

27. Stimulus appears outside of RF
Saccade moves RF to stimulus location

28. What is the brain circuit that produces remapping?

29. The obvious pathway for visual signals: forebrain commissures

30. Are the forebrain commissures necessary for updating visual signals across the vertical meridian?
Behavior in double step task
Physiology in single step and double step task

31. Attain fixation T1 appears T2 flashes briefly Saccade to T1FP
T1 appears FP T1
T2 flashes briefly T1 T2 FP
Saccade to T1 T1
Saccade to T2 T2

32. Attain fixation FP
T1 appears FP T1
T2 flashes T1 T2 FP

33. Transfer of visual signals
WITHIN T2 T1 T2

34. WITHIN T2 T1 T2
T2’

35. WITHIN
VISUAL-ACROSS T2 T1 T2 T1 T2
T2’ T2

36. WITHIN
VISUAL-ACROSS T2 T1 T2 T1 T2
T2’ T2
T2’

37. Is performance impaired on visual-across sequences in
split-brain monkeys?
WITHIN
VISUAL-ACROSS T2 T2 T1 T1 T2
T2’ T2
T2’

38. Central
Central
Within
Across
Across
Within

39. Day 1: Initial impairment for visual-across
Monkey C
Monkey E
Within
Across
Central
correct
incorrect

40. TRIALS
1-10
60-70
Within
Central
Across
Within
Central
Across

41. First day saccade endpoints
Monkey C
Vertical eye position (degrees)
Monkey E
Horizontal eye position (degrees)

42. Last day saccade endpoints
Monkey C
Vertical eye position (degrees)
Monkey E
Monkey E
Horizontal eye position (degrees)

43. Are the forebrain commissures necessary for updating spatial information across the vertical meridian?

44. Are the forebrain commissures necessary for updating spatial information across the vertical meridian?
No. The FC are the primary route but not the only route.

45. Are the forebrain commissures necessary for updating spatial information across the vertical meridian?
No. The FC are the primary route but not the only route.
What are LIP neurons doing?

46. Stimulus appears outside of RF
Saccade moves RF to stimulus location

47. SINGLE
STEP
STIMULUS ALONE
SACCADE ALONE

48. Population activity in area LIP

49. SINGLE
STEP
DOUBLE STEP

50. Split Brain Monkey Summary
The forebrain commissures normally transmit remapped visual signals across the vertical meridian but they are not required.

51. Split Brain Monkey Summary
The forebrain commissures normally transmit remapped visual signals across the vertical meridian but they are not required.
Single neurons in area LIP continue to encode remapped stimulus traces in split-brain animals.

54. Remapping in monkey area LIP and extrastriate visual cortex
2) Remapping in split-brain monkeys
Behavior
Physiology
3) Remapping in human cortex
Parietal cortex
Striate and extrastriate visual cortex

64. Functional Imaging Predictions
1) Robust activation in cortex ipsilateral to the stimulus.

65. Functional Imaging Predictions
1) Robust activation in cortex ipsilateral to the stimulus.
2) Ipsilateral activation should be smaller than the contralateral visual response.

66. Functional Imaging Predictions
1) Robust activation in cortex ipsilateral to the stimulus.
2) Ipsilateral activation should be smaller than the contralateral visual response.
3) It should not be attributable to the stimulus alone or to the saccade alone.

67. Functional Imaging Predictions
1) Robust activation in cortex ipsilateral to the stimulus.
2) Ipsilateral activation should be smaller than the contralateral visual response.
3) It should not be attributable to the stimulus alone or to the saccade alone.
4) Ipsilateral activation should occur around the time of the saccade.

71. Contralateral Visual Response

72. Ipsilateral Remapped Response

73. Ipsilateral Remapped Response

76. Visual and Remapped Responses

85. Human Parietal Imaging Summary
Remapping in humans produces activity in parietal cortex ipsilateral to the visual stimulus.

86. Human Parietal Imaging Summary
Remapping in humans produces activity in parietal cortex ipsilateral to the visual stimulus.
Remapped activity is lower amplitude than visual activity.

87. Human Parietal Imaging Summary
Remapping in humans produces activity in parietal cortex ipsilateral to the visual stimulus.
Remapped activity is lower amplitude than visual activity.
It cannot be attributed to the stimulus or the saccade alone.

88. Human Parietal Imaging Summary
Remapping in humans produces activity in parietal cortex ipsilateral to the visual stimulus.
Remapped activity is lower amplitude than visual activity.
It cannot be attributed to the stimulus or the saccade alone.
It occurs in conjunction with the eye movement.

89. Remapping in monkey area LIP and extrastriate visual cortex
2) Remapping in split-brain monkeys
Behavior
Physiology
3) Remapping in human cortex
Parietal cortex
Striate and extrastriate visual cortex

98. Contralateral Visual Response

99. Ipsilateral Remapped Response

100. Remapping in Multiple Visual Areas

101. Remapping in monkey area LIP and extrastriate visual cortex
2) Remapping in split-brain monkeys
Behavior
Physiology
3) Remapping in human cortex
Parietal cortex
Striate and extrastriate visual cortex

102. Human Imaging Summary
Remapping in humans produces activity in the hemisphere ipsilateral to the stimulus.

103. Human Imaging Summary
Remapping in humans produces activity in the hemisphere ipsilateral to the stimulus.
Remapped activity is present in human parietal, extrastriate and striate cortex.

104. Human Imaging Summary
Remapping in humans produces activity in the hemisphere ipsilateral to the stimulus.
Remapped activity is present in human parietal, extrastriate and striate cortex.
Remapped visual signals are more prevalent at higher levels of the visual system hierarchy.

105. Human Imaging Summary
Remapping in humans produces activity in the hemisphere ipsilateral to the stimulus.
Remapped activity is present in human parietal, extrastriate and striate cortex.
Remapped visual signals are more prevalent at higher levels of the visual system hierarchy.
Remapping occurs in parietal and visual cortex.

106. Conclusions
Remapping of visual signals is widespread in monkey cortex.

107. Conclusions
Remapping of visual signals is widespread in monkey cortex.
Split-brain monkeys are able to remap visual signals across the vertical meridian.

108. Conclusions
Remapping of visual signals is widespread in monkey cortex.
Split-brain monkeys are able to remap visual signals across the vertical meridian.
Remapped visual signals are present in area LIP in split-brain monkeys.

109. Conclusions
Remapping of visual signals is widespread in monkey cortex.
Split-brain monkeys are able to remap visual signals across the vertical meridian.
Remapped visual signals are present in area LIP in split-brain monkeys.
Remapped visual signals are robust in human parietal and visual cortex.

110. Conclusions
Remapping of visual signals is widespread in monkey cortex.
Split-brain monkeys are able to remap visual signals across the vertical meridian.
Remapped visual signals are present in area LIP in split-brain monkeys.
Remapped visual signals are robust in human parietal and visual cortex.
Vision is an active process of building representations from sensory, cognitive and motor signals.

113. Learning? Or a monkey trick?
Within
Across
Central

114. no monkey tricks..

115. Both monkeys really update the visual representation
Monkey EM
Monkey CH

118. Magnitude of Remapped Response

125. Intact Subjects Split Brain Subject

128. Strength of Parietal Responses in Split Brain
and Intact Subjects