Temporal preparation in patients with Neglect syndrome

Abstract

Abstract The right parietal cortex has been widely associated with a spatial orienting network. Its damage frequently produces the Neglect syndrome consisting in deficits in spatial attention to the left hemifield. Neglect has also been related to temporal deficits (such as the estimation of the duration of a stimulus or the discrimination of two stimuli that occur at the same spatial location but at different time intervals). Such attentional deficits have been much less studied in the temporal as compared to the spatial domain. The current research focused on the study of temporal attention processes in patients with Neglect syndrome, specifically, on temporal preparation. We recruited 10 patients with Neglect syndrome, 10 patients without Neglect syndrome, as well as 11 healthy individuals. Each participant completed an experimental task which measures three main temporal preparation effects described in the literature: Temporal orienting and Foreperiod effects (both related to control mechanisms and prefrontal areas) and Sequential effects (automatic in nature and related to parietal and subcortical structures). The results showed a deficit in the sequential effects only in those patients who suffered from Neglect syndrome. The results suggest a causal relation between Neglect syndrome and the automatic mechanisms of temporal preparation. Since our sample of Neglect patients had suffered lesions mainly in the parietal cortex, the results are discussed taking into account the role of the parietal lobe in the processing of time and the models explaining sequential effects.