TY - JOUR
T1 - Intra-saccadic displacement sensitivity after a lesion to the posterior parietal cortex
AU - Fabius, Jasper H
AU - Nijboer, Tanja C W
AU - Fracasso, Alessio
AU - Van der Stigchel, Stefan
N1 - Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.
PY - 2020/1
Y1 - 2020/1
N2 - Visual perception is introspectively stable and continuous across eye movements. It has been hypothesized that displacements in retinal input caused by eye movements can be dissociated from displacements in the external world using extra-retinal information, such as a corollary discharge from the oculomotor system. The extra-retinal information can inform the visual system about an upcoming eye movement and accompanying displacements in retinal input. The parietal cortex has been hypothesized to be critically involved in integrating retinal and extra-retinal information. Two tasks have been widely used to assess the quality of this integration: double-step saccades and intra-saccadic displacements. Double-step saccades performed by patients with parietal cortex lesions seemed to show hypometric second saccades. However, recently idea has been refuted by demonstrating that patients with very similar lesions were able to perform the double step saccades, albeit taking multiple saccades to reach the saccade target. So, it seems that extra-retinal information is still available for saccade execution after a lesion to the parietal lobe. Here, we investigated whether extra-retinal signals are also available for perceptual judgements in nine patients with strokes affecting the posterior parietal cortex. We assessed perceptual continuity with the intra-saccadic displacement task. We exploited the increased sensitivity when a small temporal blank is introduced after saccade offset (blank effect). The blank effect is thought to reflect the availability of extra-retinal signals for perceptual judgements. Although patients exhibited a relative difference to control subjects, they still demonstrated the blank effect. The data suggest that a lesion to the posterior parietal cortex (PPC) alters the processing of extra-retinal signals but does not abolish their influence altogether.
AB - Visual perception is introspectively stable and continuous across eye movements. It has been hypothesized that displacements in retinal input caused by eye movements can be dissociated from displacements in the external world using extra-retinal information, such as a corollary discharge from the oculomotor system. The extra-retinal information can inform the visual system about an upcoming eye movement and accompanying displacements in retinal input. The parietal cortex has been hypothesized to be critically involved in integrating retinal and extra-retinal information. Two tasks have been widely used to assess the quality of this integration: double-step saccades and intra-saccadic displacements. Double-step saccades performed by patients with parietal cortex lesions seemed to show hypometric second saccades. However, recently idea has been refuted by demonstrating that patients with very similar lesions were able to perform the double step saccades, albeit taking multiple saccades to reach the saccade target. So, it seems that extra-retinal information is still available for saccade execution after a lesion to the parietal lobe. Here, we investigated whether extra-retinal signals are also available for perceptual judgements in nine patients with strokes affecting the posterior parietal cortex. We assessed perceptual continuity with the intra-saccadic displacement task. We exploited the increased sensitivity when a small temporal blank is introduced after saccade offset (blank effect). The blank effect is thought to reflect the availability of extra-retinal signals for perceptual judgements. Although patients exhibited a relative difference to control subjects, they still demonstrated the blank effect. The data suggest that a lesion to the posterior parietal cortex (PPC) alters the processing of extra-retinal signals but does not abolish their influence altogether.
U2 - 10.1016/j.cortex.2020.01.027
DO - 10.1016/j.cortex.2020.01.027
M3 - Article
C2 - 32172025
SN - 0010-9452
VL - 127
SP - 108
EP - 119
JO - Cortex; a journal devoted to the study of the nervous system and behavior
JF - Cortex; a journal devoted to the study of the nervous system and behavior
ER -