Visuospatial imagery and working memory in schizophrenia

Abstract

Introduction The ability to form mental images that reconstruct former perceptual experiences is closely related to working memory (WM) ability. However, while WM deficits are established as a core feature of schizophrenia, an independent body of work suggests that mental imagery ability is enhanced in the disorder. Across two experiments we investigated mental imagery in schizophrenia and its relationship with WM. Methods In Experiment 1, individuals with schizophrenia (SZ: N=15) and matched controls (CO: N=14) completed a mental imagery generation and inspection task and a spatial delayed-response WM task. In Experiment 2, SZ (N=16) and CO (N=16) completed a novel version of the mental imagery task modified to increase WM maintenance demand. Results In Experiment 1, SZ demonstrated enhanced mental imagery performance, as evidenced by faster response times relative to CO, with preserved accuracy. However, enhanced mental imagery in SZ was accompanied by impaired WM as assessed by the delayed-response task. In Experiment 2, when WM maintenance load was increased, SZ no longer showed superior imagery performance. Conclusions We found evidence for enhanced imagery manipulation in SZ despite their WM maintenance deficit. However, this imagery enhancement was abolished when WM maintenance demands were increased. This profile of enhanced imagery manipulation but impaired maintenance could be used to implement novel remediation strategies in the disorder.

Effects of proactive interference on non-verbal working memory

“…If having more feature codes is critical to the resolution of PI, then the prediction would be that in Kaller et al’s (2014) study, patients with schizophrenia retrieve more feature codes with nameable objects than do healthy controls, in turn suggesting that patients have a fundamentally richer representation of the objects that mitigate PI. Consistent with this view, there is evidence of enhanced mental imagery ability in schizophrenia (Bocker et al 2000; Matthews et al 2014; Mintz and Alpert 1972; Sack et al 2005) and that visual WM and visual imagery both rely on depictive representations that share the same format (Borst et al 2012). Using the present task with non-nameable objects to examine the resolution of PI in non-verbal visual WM in schizophrenia would allow us to tease apart these two alternate hypotheses.…”

Visual working memory performance in aphantasia

“…A close correspondence between representations underlying visual working memory and visual imagery has been demonstrated, both cognitive (Borst, Ganis, Thompson, & Kosslyn, 2012), and neural (Albers, Kok, Toni, Dijkerman, & De Lange, 2013;Slotnick, Thompson, & Kosslyn, 2012). Clinical work with schizophrenic patients demonstrated that even though this patient group suffers from working memory impairments, they are faster at mental image generation than matched controls (Matthews, Collins, Thakkar, & Park, 2014). However, the same study also showed that the enhanced mental imagery capacity could be abolished by increasing the concurrent working memory load.…”

Imagine that: elevated sensory strength of mental imagery in individuals with Parkinson's disease and visual hallucinations

“…For example, patients with either schizophrenia [34] or post-traumatic stress disorder [35,36] have been shown to have increased resting activity within the ventral attention network and report more vivid mental imagery [37,38]. In addition, both disorders have displayed impairments in cognitive flexibility [39,40].…”