Functional magnetic resonance imaging study of external source memory and its relation to cognitive insight in non-clinical subjects

VR for Cognition and Memory

This chapter will provide a review of research into human cognition through the lens of VR-based paradigms for studying memory. Emphasis is placed on why VR increases the ecological validity of memory research and the implications of such enhancements.

Brain areas associated with clinical and cognitive insight in psychotic disorders: A systematic review and meta-analysis

In the past years, ample interest in brain abnormalities related to clinical and cognitive insight in psychosis has contributed several neuroimaging studies to the literature. In the current study, published findings on the neural substrates of clinical and cognitive insight in psychosis are integrated by performing a systematic review and meta-analysis. Coordinate-based meta-analyses were performed with the parametric coordinate-based meta-analysis approach, non-coordinate based meta-analyses were conducted with the metafor package in R. Papers that could not be included in the meta-analyses were systematically reviewed. Thirty-seven studies were retrieved, of which 21 studies were included in meta-analyses. Poorer clinical insight was related to smaller whole brain gray and white matter volume and gray matter volume of the frontal gyri. Cognitive insight was predominantly positively associated with structure and function of the hippocampus and ventrolateral prefrontal cortex. Impaired clinical insight is not associated with abnormalities of isolated brain regions, but with spatially diffuse global and frontal abnormalities suggesting it might rely on a range of cognitive and self-evaluative processes. Cognitive insight is associated with specific areas and appears to rely more on retrieving and integrating self-related information.

Trait self-reflectiveness relates to time-varying dynamics of resting state functional connectivity and underlying structural connectomes: Role of the default mode network

BACKGROUND

Cognitive insight is defined as the ability to reflect upon oneself (i.e. self-reflectiveness), and to not be overly confident of one's own (incorrect) beliefs (i.e. self-certainty). These abilities are impaired in several disorders, while they are essential for the evaluation and regulation of one's behavior. We hypothesized that cognitive insight is a dynamic process, and therefore examined how it relates to temporal dynamics of resting state functional connectivity (FC) and underlying structural network characteristics in 58 healthy individuals.

METHODS

Cognitive insight was measured with the Beck Cognitive Insight Scale. FC characteristics were calculated after obtaining four FC states with leading eigenvector dynamics analysis. Gray matter (GM) and DTI connectomes were based on GM similarity and probabilistic tractography. Structural graph characteristics, such as path length, clustering coefficient, and small-world coefficient, were calculated with the Brain Connectivity Toolbox. FC and structural graph characteristics were correlated with cognitive insight.

RESULTS

Individuals with lower cognitive insight switched more and spent less time in a globally synchronized state. Additionally, individuals with lower self-reflectiveness spent more time in, had a higher probability of, and had a higher chance of switching to a state entailing default mode network (DMN) areas. With lower self-reflectiveness, DTI-connectomes were segregated less (i.e. lower global clustering coefficient) with lower embeddedness of the left angular gyrus specifically (i.e. lower local clustering coefficient).

CONCLUSIONS

Our results suggest less stable functional and structural networks in individuals with poorer cognitive insight, specifically self-reflectiveness. An overly present DMN appears to play a key role in poorer self-reflectiveness.

Neural correlates of altered insight in frontotemporal dementia: a systematic review

Altered insight into disease or specific symptoms is a prominent clinical feature of frontotemporal dementia (FTD). Understanding the neural bases of insight is crucial to help improve FTD diagnosis, classification and management. A systematic review to explore the neural correlates of altered insight in FTD and associated syndromes was conducted. Insight was fractionated to examine whether altered insight into different neuropsychological/behavioural objects is underpinned by different or compatible neural correlates. 6 databases (Medline, Embase, PsycINFO, Web of Science, BIOSIS and ProQuest Dissertations & Theses Global) were interrogated between 1980 and August 2019. 15 relevant papers were found out of 660 titles screened. The studies included suggest that different objects of altered insight are associated with distinctive brain areas in FTD. For example, disease unawareness appears to predominantly correlate with right frontal involvement. In contrast, altered insight into social cognition potentially involves, in addition to frontal areas, the temporal gyrus, insula, parahippocampus and amygdala. Impaired insight into memory problems appears to be related to the frontal lobes, postcentral gyrus, parietal cortex and posterior cingulate. These results reflect to a certain extent those observed in other neurodegenerative conditions like Alzheimer's disease (AD) and also other brain disorders. Nevertheless, they should be cautiously interpreted due to variability in the methodological aspects used to reach those conclusions. Future work should triangulate different insight assessment approaches and brain imaging techniques to increase the understanding of this highly relevant clinical phenomenon in dementia.

First-person view of one's body in immersive virtual reality: Influence on episodic memory

Episodic memories (EMs) are recollections of contextually rich and personally relevant past events. EM has been linked to the sense of self, allowing one to mentally travel back in subjective time and re-experience past events. However, the sense of self has recently been linked to online multisensory processing and bodily self-consciousness (BSC). It is currently unknown whether EM depends on BSC mechanisms. Here, we used a new immersive virtual reality (VR) system that maintained the perceptual richness of life episodes and fully controlled the experimental stimuli during encoding and retrieval, including the participant’s body. Our data reveal a classical EM finding, which shows that memory for complex real-life like scenes decays over time. However, here we also report a novel finding that delayed retrieval performance can be enhanced when participants view their body as part of the virtual scene during encoding. This body effect was not observed when no virtual body or a moving control object was shown, thereby linking the sense of self, and BSC in particular, to EMs. The present VR methodology and the present behavioral findings will enable to study key aspects of EM in healthy participants and may be especially beneficial for the restoration of self-relevant memories in future experiments.

Enhancing the Ecological Validity of fMRI Memory Research Using Virtual Reality

Functional magnetic resonance imaging (fMRI) is a powerful research tool to understand the neural underpinnings of human memory. However, as memory is known to be context-dependent, differences in contexts between naturalistic settings and the MRI scanner environment may potentially confound neuroimaging findings. Virtual reality (VR) provides a unique opportunity to mitigate this issue by allowing memories to be formed and/or retrieved within immersive, navigable, visuospatial contexts. This can enhance the ecological validity of task paradigms, while still ensuring that researchers maintain experimental control over critical aspects of the learning and testing experience. This mini-review surveys the growing body of fMRI studies that have incorporated VR to address critical questions about human memory. These studies have adopted a variety of approaches, including presenting research participants with VR experiences in the scanner, asking participants to retrieve information that they had previously acquired in a VR environment, or identifying neural correlates of behavioral metrics obtained through VR-based tasks performed outside the scanner. Although most such studies to date have focused on spatial or navigational memory, we also discuss the promise of VR in aiding other areas of memory research and facilitating research into clinical disorders.

A longitudinal study of cognitive insight and cortical thickness in first-episode psychosis

Among individuals with psychosis, those with poor cognitive insight (lower Self-Reflectiveness, higher Self-Certainty) show volumetric reductions in cortical structure. We evaluated whether changes in cognitive insight are associated with progressive changes in cortical structure in first-episode psychosis (FEP) and control subjects. Beck Cognitive Insight Scale ratings and magnetic resonance imaging scans were acquired at baseline for 130 FEP and 52 controls, 59 FEP and 28 controls at 1-year, and 53 FEP and 20 controls at 2-years. Cortical thickness was computed across scans and analyzed with linear mixed models. At baseline, groups did not differ on Self-Reflectiveness or Self-Certainty. At baseline, higher Self-Reflectiveness significantly correlated with thinner right occipital cortex in FEP, and higher Self-Certainty was significantly negatively correlated with cortical thickness in left posterior cingulate in controls. Longitudinal analysis showed that Self-Reflectiveness and Self-Certainty did not change over time in either group. Interestingly, the lack of change in cognitive insight aligned with longitudinal cortical thickness results, where no interaction effects were seen with cortical thickness between time and either Self-Reflectiveness or Self-Certainty. Exploratory analyses with a reduced threshold found that in FEP, across all time-points, higher Self-Certainty associated with thinner cortex in left posterior cingulate/precuneus. Results suggest that the posterior cingulate may be a common neural correlate for Self-Certainty in FEP and non-clinical subjects.

Right Frontotemporal Cortex Mediates the Relationship between Cognitive Insight and Subjective Quality of Life in Patients with Schizophrenia

Although prior studies identified a relationship between cognitive insight and subjective quality of life (QOL) in patients with schizophrenia, the brain regions mediating this relationship remain unknown. Recent studies have shown that the ventrolateral prefrontal cortex may be particularly important for cognitive insight in individuals with schizophrenia. Here, we examined whether frontotemporal function mediates the relationship between cognitive insight and QOL in 64 participants, including 32 patients with schizophrenia and 32 healthy controls. Cognitive insight was measured using the Beck Cognitive Insight Scale (BCIS), while participants' subjective QOL was assessed using the Medical Outcomes Study 36-item Short-form Health Survey. Frontotemporal function was evaluated during a verbal fluency task using multichannel near-infrared spectroscopy. Consistent with previous findings, we found that frontotemporal function was impaired in patients with schizophrenia. Interestingly, our data also revealed that the right ventrolateral PFC and the right anterior part of the temporal cortex significantly mediated the relationship between the self-reflectiveness (SR) subscale of the BCIS and subjective QOL. These findings suggest that cognitive insight, particularly SR, is associated with subjective QOL in patients with schizophrenia via right frontotemporal function. The findings of this study provide important insight into a QOL model of schizophrenia, which may guide the development of cost-effective interventions that target frontotemporal function in patients with schizophrenia.

The metabolic basis of cognitive insight in psychosis: A positron emission tomography study

The purpose of this study was to investigate the relationship between cognitive insight and cerebral metabolism in patients suffering from psychosis. The Beck Cognitive Insight Scale (BCIS) was administered to 63 patients with psychosis undergoing Positron Emission Tomography investigation. The sample was divided into two groups considering the BCIS score. Data were analyzed using Statistical Parametric Mapping.

RESULTS

patients with low insight, compared to those with high insight, showed decreased metabolism in the right fusiform gyrus, left precuneus, superior temporal gyrus and insula bilaterally, as well as increased metabolism in the left orbito-frontal gyrus (all p<0.005). Our results suggest that reduced posterior (occipito-temporo-insulo-parietal) and increased anterior (orbitofrontal) cerebral metabolism may sustain low cognitive insight in psychosis.

Unrealistic self-overconfidence in schizophrenia is associated with left presubiculum atrophy and impaired episodic memory

The study aimed at investigating the role of the hippocampal subfields in cognitive insight and the clinical and neuropsychological underpinnings of the related two sub-dimensions, Self-Reflectiveness (SR), i.e., openness to external feedback, and Self-Certainty (SC), i.e., unrealistic overconfidence in one's opinions. In order to do this, 45 patients with a diagnosis of schizophrenia and 45 age- and gender-matched healthy control subjects (HC) were administered the Beck Cognitive Insight Scale (BCIS), along with neuropsychological, clinical and psychopathological assessment, and underwent an MRI investigation. Hippocampal segmentation was carried out. Regression analyses were performed for BCIS indexes, volumetric parameters of hippocampal subfields and clinical and neuropsychological variables. Results highlighted that in the schizophrenia group, higher levels of SC were related to reduced volume of the left presubiculum, and worse episodic memory. No significant relationship emerged for the SR index. There was no significant relationship between any of the BCIS indexes and volumetric data of the hippocampal subfields in the HC group. Our data support the hypothesis that unrealistic self-overconfidence in schizophrenia is related to the hippocampal presubiculum atrophy, which is involved in episodic memory and cognitive control and is supposed to be underpinned by difficulty in integrating new memories and thus in generating new hypotheses about the self.

The relationship between cognitive insight and depression in psychosis and schizophrenia: a review and meta-analysis

Lack of insight is a commonly observed problem in patients with psychosis and schizophrenia. Clinical insight in patients has been associated with low mood. Cognitive insight is a recently defined concept, relating to the ability to self-reflect and the degree to which patients are over-confident regarding their interpretations of illness-related experiences, and is related to clinical insight. We therefore sought to investigate whether there is a positive relationship between cognitive insight and mood. A literature search identified 17 relevant papers published between 2004 and 2014. Our analysis indicated that there was a small but significant positive correlation between the composite index (CI) of the Beck Cognitive Insight Scale (BCIS) and depression scores, but this was driven by a significant positive relationship between depression and the BCIS self-reflection (SR) sub-scale, where low mood was related to higher SR scores. There was no significant relationship between the self-certainty sub-scale and depression. Post-hoc analysis indicated that different depression scales did not significantly affect the relationship with SR. Our results support the idea that cognitive insight is significantly related to mood in schizophrenia, and the effect size is similar to that between clinical insight and mood. Potential applications of this knowledge into treatment and rehabilitation are discussed and a model of cognitive insight is proposed.

Cognitive insight in first-episode schizophrenia: further evidence for a role of the ventrolateral prefrontal cortex

In people with psychoses, Self-Reflectiveness may rely on the right ventrolateral prefrontal cortex (VLPFC). We used functional magnetic resonance imaging (fMRI) and a novel virtual reality paradigm to evaluate the role of the VLPFC for Self-Reflectiveness in 25 first-episode of schizophrenia (FES) participants and 24 controls. Participants first viewed 20 characters each paired with a unique object/location, and later completed source memory judgements during fMRI scanning. Self-Reflectiveness, measured with the Beck Cognitive Insight Scale, was significantly and positively correlated to activation in bilateral VLPFC in FES, but not in controls, providing further evidence that the VLPFC supports Self-Reflectiveness in FES.

Cognitive insight in schizophrenia patients and their biological parents: a pilot study

BACKGROUND

Clinical insight in schizophrenia patients is partly associated with familial environment but has been poorly studied to date. We aimed to explore (1) the relationship between parents' cognitive insight and their offspring's; (2) the relationship between parents' cognitive insight and their clinical insight into the disease of their offspring; and (3) the clinical and cognitive determinants of cognitive insight in parents.

METHODS

Cognitive insight was assessed in 37 patient-biological parent pairs/dyads with the Beck Cognitive Insight Scale (BCIS). Other measures included the Scale to assess Unawareness of Mental Disorder and cognitive assessments.

RESULTS

We found no significant association between parents' cognitive insight and their offspring's. Conversely, a positive association between parents' cognitive insight and parents' insight into their offspring's symptoms was found. Better awareness of their offspring's specific symptoms was associated with lower levels of overconfidence in one's beliefs and with BCIS total score. BCIS Self-Certainty and BCIS total score were associated with better executive functioning and verbal comprehension.

CONCLUSIONS

Better insight into their offspring's symptoms is associated with cognitive insight in biological parents of schizophrenia patients. Our results support the integration of cognitive intervention targeting parents' cognitive flexibility in family psychoeducational programs and provide an important first step towards developing a more refined understanding of the factors involved in insight into symptoms of illness in parents of schizophrenia patients.