Underestimation of contralateral space in neglect: A deficit in the "where" task

Sabrina Pitzalis, Francesco Di Russo, Francesca Figliozzi, Donatella Spinelli

Research output: Contribution to journalArticle

Abstract

Space perception was investigated in right brain damaged patients with (N=13) and without neglect (N=5; control group). Patients were requested to localise a target tachistoscopically flashed at various eccentricities along the horizontal meridian. All patients had an intact visual field and spared ability to manually point to a target. To segregate magno- and parvo-pathway activity, stimuli modulated in either luminance or chromatic contrast were used. Patients were required to verbally report the stimulus position (verbal task) or to manually point to the stimulus (pointing task). Neglect patients reported the stimuli in the left visual field closer to the centre than they actually were. In the verbal test, underestimation was about 7 deg at the most eccentric position tested (20 deg), and decreased linearly for smaller eccentricities. The effect was similar but less marked in the pointing task. No difference was found for stimuli with luminance or chromatic contrast. Space underestimation was confined to the contralesional space; no evidence of misperception was detected in the ipsilesional hemifield. The present findings are consistent with the view that contralesional space representation is compressed in neglect patients.

Original languageEnglish
Pages (from-to)319-328
Number of pages10
JournalExperimental Brain Research
Volume159
Issue number3
DOIs
Publication statusPublished - Dec 2004

Keywords

  • Magno vs. parvo systems
  • Misperception
  • Neglect
  • Perceptual vs. motor
  • Space
  • Stimulus contrast

ASJC Scopus subject areas

  • Neuroscience(all)

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