Visual masking in schizophrenia: overview and theoretical implications

Abstract

Visual masking provides several key advantages for exploring the earliest stages of visual processing in schizophrenia: it allows for control over timing at the millisecond level, there are several well-supported theories of the underlying neurobiology of visual masking, and it is amenable to examination by electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI). In this paper, we provide an overview of the visual masking impairment schizophrenia, including the relevant theoretical mechanisms for masking impairment. We will discuss its relationship to clinical symptoms, antipsychotic medications, diagnostic specificity, and presence in at-risk populations. As part of this overview, we will cover the neural correlates of visual masking based on recent findings from EEG and fMRI. Finally, we will suggest a possible mechanism that could explain the patterns of masking findings and other visual processing findings in schizophrenia.

Fig. 1.

Examples of targets, masks, and response functions from different masking paradigms. For these tasks, participants were asked to identify the location of gap in one side of a square. In the first two types of masking, the target could appear in one of four possible locations on the screen. In the case of 4-dot masking, the mask specified which square in an array of 4 squares was the target.