Abstract
Previous studies have shown that mental representational disorders affect specific mechanisms that subserve human orientation. Specifically, representational neglect impairs the ability to reorient oneself in a new environment. Apparently, the inability of patients with this disorder to manipulate a mental representation of the environment prevents them from using their previous navigational experience. In this study, we compared representational neglect patients' performance with the performance of other groups of brain-damaged patients (left and right lesions) without representational disorders and healthy participants during navigation in a virtual maze with and without local landmarks. The virtual environment allows to observe navigation ruling out vestibular and proprioceptive information about linear and angular movements that could explain results of previous studies and to shed some light on navigational disorders shown by perceptual and representational neglect patients. We found that brain-damaged patients without neglect and healthy participants showed no deficits in navigation. Further perceptual and representational neglect patients performed poorly across experimental conditions. Finally, only the representational neglect patients group was unable to build or retrieve the mental representation of a new environment.
Acknowledgments
This study was partially supported by funding from Ministero dell'Istruzione dell'Università e della Ricerca (PRIN: Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale 2003), Ministero della Salute (RC 2004–2005), and the European Community (Eu 6th NEST Pathfinder Project: Wayfinding No. 12959). The author wishes to thank C. Guariglia and D. Nico for their insightful comments. Special thanks goes to Marisa Denos for her crucial comments and critical reading of this manuscript.
Notes
1 LQ = (number of left-sided items – number of right-sided items)/(number of left-sided items + number of right-sided items) × 100.