Remembering verbally-presented items as pictures: Brain activity underlying visual mental images in schizophrenia patients with visual hallucinations

Abstract

Background: Previous research suggests that visual hallucinations in schizophrenia consist of mental images mistaken for percepts due to failure of the reality-monitoring processes. However, the neural substrates that underpin such dysfunction are currently unknown. We conducted a brain imaging study to investigate the role of visual mental imagery in visual hallucinations. Method: Twenty-three patients with schizophrenia and 26 healthy participants were administered a reality-monitoring task whilst undergoing an fMRI protocol. At the encoding phase, a mixture of pictures of common items and labels designating common items were presented. On the memory test,

Reality-monitoring deficits and visual hallucinations in schizophrenia

“…The existence of a misattribution bias in patients with VH has already been described in the literature in schizophrenia [14–16, 25]. For instance, Brébion et al (2008) found that patients with VH were more likely to report that they had seen pictures of items when only the verbal label of these items had been displayed.…”

Perceptual Representations and the Vividness of Stimulus-Triggered and Stimulus-Independent Experiences

“…The vividness of these experiences plays an important role in structuring our phenomenological lives (Morales, 2019) and has significant cognitive effects. For example, vivid dream contents are easier to remember (Cohen & MacNeilage, 1974), vivid mental imagery elicits incidental recall (D’Angiulli et al, 2013) and can even lead to false remembering (Gonsalves et al, 2004), metaconsciousness in mind wandering is more sensitive to vivid experiences (Schooler, 2002), and vivid hallucinations feel more realistic (Stephan-Otto et al, 2017).…”

“…The mental images formed during hallucinations might thus be more vivid (both in the intensity and specificity sense) than during nonhallucinatory mental imagery. This might be a reason why individuals with hallucinations do not question the reality of the contents of these mental images (Stephan-Otto et al, 2017). The vividness of conscious experiences might thus provide an important clue for metacognitive judgments about whether the contents presented in the experience are real or not.…”

Antipsychotic agents deteriorate brain and retinal function in schizophrenia patients with combined auditory and visual hallucinations: A pilot study and secondary follow‐up study

“…In addition, VHs have also been observed in children, adolescents, and young adults at a high risk for schizophrenia (Garcia‐Portilla et al, 2019; Grano et al, 2015; Guidotti & Grayson, 2011; Hebert et al, 2010; Mittal, Gupta, Keane, & Silverstein, 2015). Some studies that adopted neuroimaging and neuro‐electrophysiology techniques reported that VHs are usually accompanied by brain cortex‐related functional and structural alterations (Henke, Robinson, Drysdale, & Loxley, 2014; Pajani, Kok, Kouider, & Lange, 2015; Stephan‐Otto et al, 2017). Most of those studies reported that functional disturbances in the visual cortex and parietal cortex, and structural alterations in the brain gray matter volume (GMV) were characteristic of VHs (De Haan, Nys, Zandvoort, & Ramsey, 2007; Garcia‐Portilla et al, 2019; Grano et al, 2015; Guidotti & Grayson, 2011; Hebert et al, 2010; Henke et al, 2014; Mittal et al, 2015; Oertel et al, 2007; Pajani et al, 2015; Stephan‐Otto et al, 2017).…”

“…Some studies that adopted neuroimaging and neuro‐electrophysiology techniques reported that VHs are usually accompanied by brain cortex‐related functional and structural alterations (Henke, Robinson, Drysdale, & Loxley, 2014; Pajani, Kok, Kouider, & Lange, 2015; Stephan‐Otto et al, 2017). Most of those studies reported that functional disturbances in the visual cortex and parietal cortex, and structural alterations in the brain gray matter volume (GMV) were characteristic of VHs (De Haan, Nys, Zandvoort, & Ramsey, 2007; Garcia‐Portilla et al, 2019; Grano et al, 2015; Guidotti & Grayson, 2011; Hebert et al, 2010; Henke et al, 2014; Mittal et al, 2015; Oertel et al, 2007; Pajani et al, 2015; Stephan‐Otto et al, 2017). Several previous studies have reported that VHs are also accompanied by visual perception organization‐related impairments, especially retinal thickness impairments (Lee et al, 2014; Schönfeldt‐Lecuona et al, 2019).…”