Special issue: Research report Are drawing perseverations part of the neglect syndrome? Lorenzo Pia a,b, *, Alessia Folegatti a , Marilena Guagliardo a , Rosanna Genero c and Patrizia Gindri d a Psychology Department, University of Turin, Turin, Italy b Neuroscience Institute of Turin (NIT), University of Turin, Turin, Italy c Papa Giovanni XXIII Hospital, Pianezza, Turin, Italy d San Camillo Hospital, Turin, Italy article info Article history: Received 29 June 2007 Reviewed 16 October 2007 Revised 1 November 2007 Accepted 28 November 2007 Published online 11 July 2008 Keywords: Perseverative behavior Perseverations Spatial neglect Right hemisphere lesion Basal ganglia abstract Unilateral neglect patients typically omit to cancel contralesional targets. Moreover, they can repeatedly cancel ipsilesional stimuli exhibiting what is termed ‘perseverative behavior’. Two alternative accounts of this behavior have been proposed. According to one of them, it is considered as integral to neglect and due either to a perceptual (allochiria), or a premotor (directional hypokinesia) pathological mechanism leading to the ipsilesional displacement of contralesional responses. According to the other one, perseverations are interpreted as the consequence of motor–control–disinhibition co-occurring with, although independent of, spatial neglect. We compared some crucial predictions of these two hypotheses on a group of 10 right-brain-damaged patients, eight with neglect and two without neglect, showing a perseverative behavior in both conventional and experimental cancellation tasks. In our experiment, the spatial location and the numerosity of targets were manipulated to obtain different degrees of horizontal alignment between targets on the left and on the right of the central vertical axis of the sheet. We found that ipsilesional perseverations were not influenced by left neglected targets and were not correlated to neglect severity. Additionally, perseverative errors were associated with right basal ganglia lesions rather than with presence of neglect. These findings support the view that two different pathological mechanisms might be involved in left spatial neglect and ipsilesional perseverative behavior. ª 2008 Elsevier Srl. All rights reserved. 1. Introduction Patients affected by left unilateral neglect fail to perceive or respond to stimuli presented within the contralesional space (Driver and Mattingley, 1998; Halligan et al., 2003). Accord- ingly, when asked to cross-out all the targets printed on a sheet of paper (Albert, 1973; Diller and Weinberg, 1977; Gauthier et al., 1989; Halligan et al., 1990; Ruff et al., 1986), they tend to mark ipsilesional stimuli ignoring those located con- tralesionally. Besides, they may also display a perseverative behavior (Luria, 1965), i.e., re-cancellations of ipsilesional targets (Bottini and Toraldo, 2003; Manly et al., 2002; Mark et al., 1988; Na et al., 1999; Nys et al., 2006; Rusconi et al., 2002; Vallar et al., 2006). This phenomenon has been reported quite frequently in concomitance with spatial neglect (30% Na et al., 1999 to 90% Rusconi et al., 2002) and different interpretations * Corresponding author. Psychology Department, Neuropsychology Research Group, University of Turin, Via Po 14, 10123 Turin, Italy. E-mail address: l_pia@psych.unito.it (L. Pia). available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/cortex 0010-9452/$ – see front matter ª 2008 Elsevier Srl. All rights reserved. doi:10.1016/j.cortex.2007.11.015 cortex 45 (2009) 293–299