Bourgeois, A. 1 , Chica, A. 1 , Migliaccio, R. 1, 3 , Thiebaut de Schotten, M. 1, 4 , Valero Cabre, A. 1 & Bartolomeo, P. 1, 2, 3
1 Inserm-UPMC UMRS975
2 AP-HP, Groupe hospitalier Pitié-Salpêtrière, Paris, France
3 Department of Psychology, Catholic University, Milan, Italy
4 Natbrainlab, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College, London, UK
When two consecutive events appear at the same spatial location, responses to the second event are slower than those to the first. This effect, known as inhibition of return (IOR), reflects a bias to preferentially attend to novel locations, which is necessary to explore our environment efficiently. We demonstrate that patients with right brain damage and left neglect present an impaired IOR under cover orienting situations, while saccadic IOR (overt orienting) is preserved (Bourgeois et al., under review). Neuroanatomical data demonstrate that all neglect patients with impaired covert IOR presented parietal damage or fronto-parietal disconnection. We used then an off-line repetitive Transcranial Magnetic Stimulation (rTMS) to determine the role of two parietal regions (right intraparietal sulcus -IPS, and right temporo-parietal junction -TPJ) in covert and overt IOR in healthy participants. We demonstrate that TMS over TPJ replicates IOR impairments observed in neglect patients. TMS over IPS affects both covert and overt orienting. Understanding the neural basis of covert and overt IOR is crucial for understanding attentional orienting and their underlying neural mechanisms in both the healthy and damaged brain.