Neglect symptoms are related to a prediction-hypersensitivity in ipsilesional space

The precise cognitive mechanisms underlying spatial neglect are not fully understood. Recent studies have provided the first evidence for aberrant behavioral and electrophysiological prediction and prediction error responses in patients with neglect, but also in right-hemispheric (RH) stroke patients without neglect. For prediction-dependent attention, as assessed with Posner-type cueing paradigms with volatile cue-target contingencies, studies in healthy volunteers point to a crucial role of the right temporo-parietal junction (rTPJ) – as part of a network commonly disrupted in neglect. In order to study altered prediction-dependent attention in patients with RH damage and neglect, the present study employed a spatial cueing paradigm with unsignalled changes in the cue’s predictive value in 26 RH patients, 21 left-hemispheric (LH) patients, and 33 healthy elderly controls. The inference of the changing cue’s predictive value was assessed with a Rescorla-Wagner learning model of response times (RTs) and participants' ratings. We tested for lesion-side-dependent relationships between the computational model parameters, ratings, and neuropsychological performance. Moreover, we investigated links between the behavioral signatures of predictive processing and lesion anatomy (lesion location and disconnection). The results provided no evidence for a predictive inference deficit, but revealed a correlation between a hypersensitivity of RTs to inferred predictions for ipsilesional stimuli and neglect symptoms in RH patients. Irrespective of symptoms of neglect, the rating of the cue’s predictive value deviated more from the actual values in RH patients. RT hypersensitivity for ipsilesional targets was linked to disconnection within fronto-parietal, fronto-occipital, and temporo-parietal pathways. These findings provide novel insights into the role of altered prediction-dependent processing for neglect as assessed by different read-outs, highlighting an exaggerated response adaption to predictions of ipsilesional stimuli.