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Neurocognitive Dysfunction in Schizophrenia Attention/Vigilance - - PowerPoint PPT Presentation
Neurocognitive Dysfunction in Schizophrenia Attention/Vigilance - - PowerPoint PPT Presentation
Neurocognitive Dysfunction in Schizophrenia Attention/Vigilance Immediate Memory Secondary Memory Verbal Fluency, Learning Spatial Working Memory Motor Reaction Time Processing Speed Executive Functions Visual-motor Skills Early Visual
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Perceptual/Sensory Dysfunction in Schizophrenia: Visual System
- Abnormal Smooth Pursuit Eye Movements
- ↓ Amplitude of ssVEPs to magnocellular-biased
stimuli, but not parvocellular-biased stimuli
- ↑ Sensitivity to Backward Masking
- Impaired Motion Perception
- Impaired Spatial Localization
- Impaired Detection of Simple Visual Stimuli
- Impaired Stereopsis (binocular depth perception)
- ↑ Visual Thresholds
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Sensory Dysfunction in Early Visual Processing
- Eye tracking dysfunction
↓ Acceleration (open loop gain)/delayed initiation Impaired Motion Perception - ↑ velocity discrimination thresholds ↑ Velocity discrimination thresholds correlated with ↓ pursuit acceleration
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Sensory Dysfunction in Early Visual Processing
- Eye tracking dysfunction
↓ Acceleration (open loop gain)/ delayed initiation Impaired Motion Perception - ↑ velocity discrimination thresholds ↑ Velocity discrimination thresholds correlated with ↓ pursuit acceleration
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Sensory Dysfunction in Early Visual Processing
- Eye tracking dysfunction
↓ Acceleration (open loop gain)/ delayed initiation Impaired Motion Perception - ↑ velocity discrimination thresholds ↑ Velocity Discrimination Threshold (↓ contrast sensitivity) correlated with ↓ pursuit acceleration
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Chen et al, 2006
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Sensory Dysfunction in Early Visual Processing
- ↓ Amplitude of ssVEPs to magnocellular-biased stimuli -
- but not to parvocellular-biased stimuli
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Butler et al, 2001
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Sensory Dysfunction in Early Visual Processing ↓ Amplitude of ssVEPs to magnocellular-biased stimuli correlates with velocity discrimination thresholds Not true for parvocellular-biased stimuli
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Kim et al, 2006
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Butler et al, 2005
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Increased Sensitivity to Backward Masking -- Persistence of Masking Effect
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Green et al. 1994
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Perceptual/Sensory Dysfunction in Schizophrenia: Magnocellular Input to Dorsal Stream
- ↑ Sensitivity to Backward Masking
- Impaired Motion Perception
- ↓ Acceleration (open loop gain)
- ↓ ssVEP Amplitude
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Butler, P.D. et al. Dysfunction in early-stage visual processing in schizophrenia. Am J Psychiatry, 2001; 158:1126-1133. Butler, P.D. et al. Early-stage visual processing and cortical amplification deficits in
- schizophrenia. Arch Gen Psychiatry, 2005; 62: 495-504.
Chen, Y. et al. Psychophysical isolation of a motion processing deficit in schizophrenics and their relatives and its association with impaired smooth pursuit. Proc Nat'l Acad Sci, 1999; 96: 4724-4729. Green, M.F. et al. Backward masking in schizophrenia and mania: I. Specifying a
- mechanism. Arch Gen Psychiatry, 1994; 51: 939-944.
Holzman, P.S. and D.L. Levy, Eye tracking dysfunction and mental illness. Encyclopedia
- f Neuroscience, ed. G. Adelman and B. Smith. 2003: Elsevier. (CD ROM and Book).
Kim, D. et al. Dysfunction in early-stage visual processing in schizophrenia: harmonic
- analysis. Schiz Res, 2005. 76: p. 55-65.
Kim, D. et al. Magnocellular contributions to impaired motion processing in
- schizophrenia. Schiz Res, 2006. 82: p. 1-8.
Levy, D.L. et al. Eye tracking dysfunction and schizophrenia: A critical perspective. Schiz Bull, 1993. 19: p. 461-536. Schechter, I. et al A new dimension of sensory dysfunction: Stereopsis deficits in
- schizophrenia. Biol Psychiatry, 2006; on-line.