Group A3 Presenters Anastasia Christopher Carol Rego Sarah McNeil Technical Experts Bonnie Chan Herman Gill Marisa Leung Brief overview of Module 3 Background information and important definitions ID: 498782
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Slide1
Receptive Field Dynamics in Adult Primary Visual Cortex
Group A3
Presenters: Anastasia Christopher, Carol
Rego
, Sarah McNeil
Technical Experts: Bonnie Chan, Herman Gill, Marisa LeungSlide2
Brief overview of Module 3
Background information and important definitions
Anatomy of the brainLateral Geniculate NucleusMethodResultsPrimary Visual CortexMethodResultsConclusion
Table of Contents
Anastasia ChristopherSlide3
By: Charles Gilbert and
Torsten
WieselReceptive Field Dynamics in Adult Primary Visual CortexAnastasia ChristopherSlide4
Important Definitions
Receptive Field Size
Cortical Topography
Binocular Retinal Lesion
Scotoma
Anastasia ChristopherSlide5
Is the locus of change in regards to sensory input located at the cortical level (
Primary Visual Cortex) or at a prior stage in the sensory pathway (Lateral Geniculate Nucleus)?Anastasia ChristopherSlide6
Lateral
Geniculate
Nucleus (LGN) Anastasia ChristopherSlide7
Primary Visual Cortex
Anastasia ChristopherSlide8
Immediately
After Lesion
2 Months After LesionLGNPrimary Visual CortexAnastasia ChristopherSlide9
Studied 2 cats and 1 monkeyTopographical mapping of the LGN
Multiple electrode penetrations across the LGN
Two injections of retrograde tracers in V1LGN - MethodsCarol RegoSlide10
Large silent area about 1mm in diameterShift in RF position
LGN – Electrode Readings
Carol RegoSlide11
Immediately
After Lesion
2 Months After LesionLGN________________ Large silent area Shift in RF position No evidence in plasticity observedPrimary Visual Cortex
________________
________________
Carol
RegoSlide12
Studied 4 cats and 6 monkeysRF maps were made using vertical electrode penetration
RF maps were made at the same sites before, immediately after, and 2 months after making the lesion
Primary Visual Cortex - MethodsSarah McNeilSlide13
Immediately after:
Inactivity in original sites
5X larger sitesCentrifugal shiftPrimary Visual Cortex - ResultsSarah McNeil
Before lesion
Immediately after lesionSlide14
2 months after:
RF field size shrunk
5˚ centrifugal shift in positionArea of activity expanded beyond affected areaPrimary Visual Cortex - Results
Sarah McNeil
Before Lesion
2 Months After LesionSlide15
Initial shock
Long term consolidation
Sarah McNeilSlide16
Immediately
After Lesion
2 Months After LesionLGN________________ Large silent area Shift in RF position No evidence in plasticity observedPrimary Visual Cortex
5X larger in RF sites
Centrifugal shift >1
˚
RF field size shrunk to several times the original size
Area of activity expanded
Centrifugal
shift 5
˚
Sarah McNeilSlide17
Anastasia Christopher
Is the locus of change in regards to sensory input located at the cortical level (Primary Visual Cortex) or at a prior stage in the sensory pathway (Lateral Geniculate Nucleus)?Slide18
Brain is high in plasticity
Compensation of damaged tissue as a result of binocular retinal lesions does not take place in LGN
Takes place at the cortical level of V1ConclusionAnastasia Christopher