Bisection of horizontal lines and of the Brentano form of the Müller-Lyer illusion was investigated in six right brain-damaged patients with left spatial hemineglect, and in six control subjects. Patients bisected the lines to the right of the objective mid- point. Comparable illusory e ects on line bisection were however found in both patients and control subjects. Relative to the baseline condition, in both groups the subjective midpoint was displaced towards the side expanded by the illusion, both leftwards and rightwards. By contrast, line length and spatial position of the stimulus had di erential e ects. In neglect patients, the rightward bisection error increased disproportionately with line length, and when the stimulus was located in the left, neglected, side of egocentric space. Control subjects showed no such e ects. The suggestion is made that the visual, non- egocentric, processes underlying these illusory e ects of length may be spared in patients with left spatial neglect. The possible neural basis of this dissociation is discussed.

Vallar, G., Daini, R., Antonucci, G. (2000). Processing of illusion of length in spatial hemineglect. A study of the line bisection. NEUROPSYCHOLOGIA, 38, 1087-1097.

Processing of illusion of length in spatial hemineglect. A study of the line bisection

VALLAR, GIUSEPPE;DAINI, ROBERTA;
2000

Abstract

Bisection of horizontal lines and of the Brentano form of the Müller-Lyer illusion was investigated in six right brain-damaged patients with left spatial hemineglect, and in six control subjects. Patients bisected the lines to the right of the objective mid- point. Comparable illusory e ects on line bisection were however found in both patients and control subjects. Relative to the baseline condition, in both groups the subjective midpoint was displaced towards the side expanded by the illusion, both leftwards and rightwards. By contrast, line length and spatial position of the stimulus had di erential e ects. In neglect patients, the rightward bisection error increased disproportionately with line length, and when the stimulus was located in the left, neglected, side of egocentric space. Control subjects showed no such e ects. The suggestion is made that the visual, non- egocentric, processes underlying these illusory e ects of length may be spared in patients with left spatial neglect. The possible neural basis of this dissociation is discussed.
Articolo in rivista - Articolo scientifico
line bisection; unilateral spatial neglect; brain-damaged patients; visual illusions.
English
1087
1097
Vallar, G., Daini, R., Antonucci, G. (2000). Processing of illusion of length in spatial hemineglect. A study of the line bisection. NEUROPSYCHOLOGIA, 38, 1087-1097.
Vallar, G; Daini, R; Antonucci, G
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/4253
Citazioni
  • Scopus 61
  • ???jsp.display-item.citation.isi??? ND
Social impact