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- 1Behavioral Deficits and Cortical Damage Loci in Cerebral AchromatopsiaKeywords: Color, Dyschromatopsia, lesions, prosopagnosia, vision
- 2AchromatopsiaVisual disorder causing absence of color vision, aka colorblind
Typically a lot of cortical damage happens - 3prosopagnosiathe inability to recognize the faces of familiar people because of a brain injury
- 4dyschromatopsiadisorder of color vision, example: one type of color blind versus not being able to see colors
- 5Lesion overlap by hand1. CT or MRI scans in horizontal sections
2. Clearly visible lesions
3. Identifiable landmarks
Then all lesions superimposed on each other - 6How to test color visionFarnsworth-Munsell 15
Ishihara isochromatic plates
100 hue test - 7Scotomasa partial loss of vision, or a blindspot
more likely to be in the left visual field
upper field are also the most common - 8Lesion Scans horizontal A- all people with achromatopsia or with prosopagnosia
- 9—Overlap of Achromatopsia lesions are more focused.
- 10—so both put together; peak activations
shown
- 11Region of damage in most people with achromatopsiathe critical region may be around v4v, v8, and v4a
- 12Overall idea Behavioral Deficits and Cortical Damage Loci in Cerebral AchromatopsiaColor perception is not localized to just one area, rather a stream of processing that flows through multiple multipurpose visual areas
Achromatopsia likely results from the lesion of one critical step in the many stages of processing that support color perception. - 13Decoding the visual and subjective contents of the human brainKeywords: fMRI, V1,
- 14fundamental features for visual perceptionorientation, color, motion, edge orientation
- 15can activity patterns in the human visual cortex reveal what stimulus orientation a person is viewing or attending to on a given trial?So they use ensemble feature selectivity, which uses population coding and multivoxel pattern analysis of fMRI data n order to decode perceived orientations
- 16Results: Decoding the visual and subjective contents of the human brainout of 8 possible stimuli orientations, participants only saw one. and it was in an fMRI.
- 17orientation decoder and ensemble feature selectivityaverage response amplitude for each fMRI voxel
- 18H1: Small local biases in individual voxels allow for robust decoding of ensemble orientation selectivity
- 19H2: Orientation selectivity will be more pronounced in early visual processing areas (V1 and V2) than in later areas (V4 and MT)found on figure 3 and 5; figure 3; orientation selectivity diminishes in higher areas; so it's found intensely throughout V1-3
Orientation preference map shows that orientation preference isn't really localized, it's all over the place. - 20H3: Perceived orientation can be decoded using fMRIg
- 21H4: Top-down voluntary attention will affect early visual processing and bias orientation-selective signalsg
- 22Fast backprojections to the primary visual area necessary for visual awareness.Keywords: photoreceptor to higher visual area; MT+/V5; V1
- 23—
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- Flashcards on Untitled, created by lrivera5434 on 07/11/2015.
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