HEMISPATIAL
NEGLECT
unilateral
neglect
spatial neglect
neglect syndrome
neglect
HEMISPATIAL
NEGLECTegocentric
HEMISPATIAL
NEGLECTallocentric
Extinction
One circle
One circle!!!
Hemianopsia Loss of half the vision in both eyes.
Binasal hemianopsia homonymous hemianopsia
RIGHT
LEFT
RIGHTIt’s not mine!!!
Somatoparaphrenia
Cortical right brain regions that have been associated with neglect.
IPL = inferior parietal lobe
ang = angular gyrus of IPL
smg = supramarginal gyrus of IPL
TPJ = temporo-parietal junction
STG = superior temporal gyrus
IFG = inferior frontal gyrus
MFG = middle frontal gyrusParton et al (2004), Karnath et al (2001), Mort et al (2003)
Marotta et al (2002)
What does the Parietal Lobe do?
Integration of sensory information
Enables mapping of visually perceived objects to body coordinates
What can neglect tell us about cognitive functioning?
Spatial attention
Extinction Neglect
Q1: Do elementary features combine to form objects pre-attentively or attentively?
This is your target!just say if it’s there or not
Kahnaman (1973), Neisser (1967), Treisman (1988)
Neglect is an attention problem, so attentive tasks like the latter one (colour & shape variation) should be more difficult for neglect sufferers, while the earlier tasks, which required only pre-attentive processing, should be just as easy for neglect patients
Q2: Does attentional selection operate early or late
in the sequence of processing stages?
damaged right hem
isphere
intact left hemisphere
777msBerti & Rizzolatti (1992)
damaged right hem
isphere
intact left hemisphere
795msBerti & Rizzolatti (1992)
damaged right hem
isphere
intact left hemisphere
890msBerti & Rizzolatti (1992)
Summary
• Usually right lobe left neglect• PERCEPTION & ATTENTION problem,
not sense problem• damage to the ANGULAR GYRUS in the
PARIETAL lobe• Enlightening in the study of attention & in
trying to find out how much of our visual processing is pre-attentional
References• ArguinM., Joanette Y. & Cavanagh P. (1993) Visual search for feature and conjunction targets
with an attention deficit. Journal of Cognitive Neuroscience, 54, 436-452.• Berti A. & Rizzolatti G. (1992) Visual Processing without awareness: Evidence from unilateral
neglect. Journal of Cognitive Neuroscience, 4, 345-351. • Bird C. M., Malhotra P., Parton A., Coulthard E., Rushworth M. F. S. & Husain M. (2006) Visual
neglect after right posterior cerebral artery infarction. Journal of Neurology, Neurosurgery, and Psychiatry. 77: 1008-1012.
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• Driver J., Mattingley J.B., Rorden C. & Davis G. (1997). Extinction as a paradigm measure of attentional bias and restricted capacity following brain injury. In. P. Thier & H.-O. Karnath (Eds.), Parietal Lobe Contributions to Orientation in 3D Space (pp. 401-430). Heidelberg: Springer-Verlag.
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• Karnath H., Ferber S. & Himmelbach M. (2001) Spatial awareness is a function of the temporal not the posterior parietal lobe. Nature, 411:950–3.
• Mangun G. R. & Hillyard S. A. (1988) Spatial gradients of visual attention: Behavioral and electrophysiological evidence. Electroencephalography and Clinical Neurophysiology, 70, 417-428.
• Marotta J. J., McKeeff T. J. & Behrmann M. (2002) Hemispatial neglect: its effects on visual preception and visually guided grasping. Neuropsychologia, 41: 1262-1271.
• Martinez A., Anllo-Vento L., Sereno M. I., Frank L. R., Buxton R. B., Dubowitz D. J., Wong E. C., Hinrichs H., Heinze H. J. & Hillyard S. A. (1999) Involvement of striate and extrastriate visual cortical areas in spatial attention. Nature Neuroscience, 4, 364-369.
• Mesulam M. M. (1999) Spatial attention and neglect: parietal, frontal and cingulate contributions to the mental representation and attentional targeting of salient extrapersonal events. Philosophical Transactions of The Royal Society London, 354, 1325-1346.
• Mort D., Malhotra P., Mannan S., et al. (2003) The anatomy of visual neglect. Brain, 126:1986–97.
• Neisser U. (1967) Cognitive Psychology. New York: Appleton-Century-Crofts.• Parton A., Malhotra P. & Husain M. (2004) Review: Hemispatial neglect. J Neurol Neurosurg
Psychiatry, 75: 13-21.• Treisman A. (1988) Features and objects. Quarterly Journal of Experimental Psychology, 40A,
201-237.• Umilta C. (2001) Mechanisms of Attention. In Rapp B. (Ed.), The Handbook of Cognitive
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