Hemispatial neglect2007

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.

• Brefczynski J. A. & DeYoe E. A. (1999) A physiological correlate of the ‘spotlight’ of visual attention. Nature Neuroscience, 2, 370-374.

• Driver J., Baylis G. C. & Rafal R. D. (1992) Preserved figure-ground segregation and symmetry perception in visual neglect. Nature; 360(6399):73–5.

• 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.

• Heinze H., Mangun G. R., Burchert W., Hinrichs M., Scholz M., Muente T. F., Goes A., Scherg M., Johannes S., Hundeshagen H., Gazzaniga M. S. & Hillyard S. A. (1994) Combined spatial and tomporal imaging of brain activity during visual selective attention in humans. Nature, 172, 543-546.

• Joseph J. S., Chun M. M. & Nakayama K. (1997) Attentional requirements in a ‘preattentive’ feature search task. Nature, 387, 805-807.

• Kahneman D. (1973) Attention and Effort. Eglewood Cliffs, NJ: Prentice Hall.

• 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

Neuropsychology. (pp. 135-158). Taylor & Francis.