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Cognitive Neuroscience. Spatial Representation. The representation of location. How could you define my location?. Locations are defined in a relative manner; Within some frame of reference. Defining spatial locations. How are locations defined/encoded at different levels of processing?
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Cognitive Neuroscience Spatial Representation
The representation of location How could you define my location? Locations are defined in a relative manner; Within some frame of reference.
Defining spatial locations How are locations defined/encoded at different levels of processing? For ganglion cells? For cells in V1?
How is location defined? What’s the frame of reference? Retino-centric (fixation centered) frame of reference
Neuropsychological Cases SWR • 64 years old, right-handed • Left occipital infarct subsequent to surgery CS • 66 years old, right-handed • Right parietal hemorrhage subsequent to drug overdose NG • 79 years old, female, left-handed • Infarction in the left parietal white mater and anterior basal ganglia
SWR Horz reading (brief view) LVF: 64% RVF: 24% Horz reading (unrestricted) + Copy drawings + Line bisection + Line cancellation +
Examples of SWR’s reading errors: TRACK -> ‘trace” TRAIN -> “trash”
Frames of Reference SWR’s deficit is only present when fixation is fixed -> retino-centered frame of reference(hemi- field loss) Purpose?
SWR Horz reading (brief view) LVF: 64% RVF: 24% Horz reading (unrestricted) 99% Copy drawings + Line bisection + Line cancellation + Vertical reading CS LVF: 47% RVF: 83% 83% Left neglect 20% rt deviation Left neglect 96%
CS: Horizontal reading, unlimited viewing Stimulus Response tumble rumble picked backed washing shining tripped dropped pledge dredge pounce ounce clinch pinch
SWR Horz reading (brief view) LVF: 64% RVF: 24% Horz reading (unrestricted) 99% Copy drawings + Line bisection + Line cancellation + Vertical reading CS LVF: 47% RVF: 83% 83% Left neglect 20% rt deviation Left neglect 96%
Frames of Reference • Retino-centered • CS’s deficit persists despite eye movements -> attentional deficit in viewer-centered frame of reference Purpose?
SWR Horz reading (brief view) LVF: 64% RVF: 24% Horz reading (unrestricted) 99% Copy drawings + Line bisection + Line cancellation + Vertical reading CS LVF: 47% RVF: 83% 83% Left neglect 20% rt deviation Left neglect 96% NG LVF: 76% RVF: 77% 72% Right neglect-objects Right neglect Right neglect-groups 75%
NG Horizontal reading: stimulus response humid human hound house stripe strip dumb dump
SWR Horz reading (brief view) LVF: 64% RVF: 24% Horz reading (unrestricted) 99% Copy drawings + Line bisection + Line cancellation + Vertical reading CS LVF: 47% RVF: 83% 83% Left neglect 20% rt deviation Left neglect 96% NG LVF: 76% RVF: 77% 72% Right neglect-objects Right neglect Right neglect-groups 75%
Frames of Reference • Retino-centered • Viewer-centered • Object-centered Purpose?
Frames of Reference Coordinate transformation? dog + dog Retino-centered dog viewer-centered object-centered
Olson & Gettner (1995) • Studied neurons within • supplementary eye fields