Transsaccadic Perception Deficits in Schizophrenia Reflect the Improper Internal Monitoring of Eye Movement Rather Than Abnormal Sensory Processing

Abstract

These results provide a novel approach in quantifying abnormal use of CD in SZPs and provide a framework to distinguish deficits in sensory processing versus defects in the internal CD-based monitoring of movement.

The function and failure of sensory predictions

“…In sum, these predictive deficits support the assumption that schizophrenia patients may have difficulty compensating for sensory (retinal) consequences of their own eye movements parallel to findings obtained in patients with bilateral cortical lesions . They are also congruent with the assumption that patients over‐rely on retinal error signals to maintain stable pursuit or to perceive visual target displacements . Importantly, in several of these studies, perceptual deficits congruent with CD failure were related to assessments of subjective sense of agency or positive symptoms (Table ) and to delusional traits in healthy individuals .…”

“…Such increased reliance on saccade end points and variability of performance might reflect deficits in remapping shifted targets, potentially triggered by CD signal disruption. In line with these findings, schizophrenia patients had greater difficulty in detecting target location shifts …”

“…Recent studies in neuropsychiatric populations have revealed striking deficits in CD function across modalities. For example, eye movement studies in schizophrenia have shown deficits in CD function affecting visual perception . These findings are paralleled by CD deficits in the auditory system, some of which have been linked to auditory hallucinations in schizophrenia …”

Reduced transfer of visuomotor adaptation is associated with aberrant sense of agency in Schizophrenia

“…In addition, the Sense of Agency Scale (SOAS; Asai et al . 2009a, b) was used to assess sense of agency in both patients and controls (Bansal et al . 2018a) and consists of three subscales: misattribution of the agent (mental agency), uncontrollability of one’s own body (physical agency), and assertiveness in social situations (social agency).…”

AVA Christmas Meeting, Cardiff University, December 16, 2019

“…A number of tasks have been developed that claim to measure the contribution of information about the eye's position/movement to accurate judgements of object movement. These tasks are not only used to gain insight into motion processing but have also been used to investigate the underlying causes of psychosis, often relating their findings to deficits in the use of outflow, and an impairment in the ability to distinguish sensory changes due to own action from sensory changes due to events in the world (Bansal et al, 2018). However, it is not clear the tasks that have been used actually measure the same thing, nor is it clear what type of eye-position information they are actually measuring.…”