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

Authors

  • Lisa Buchy PhD,

    1. Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
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  • Colin Hawco PhD,

    1. Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
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  • Michael Bodnar PhD,

    1. Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
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  • Sarah Izadi PhD,

    1. Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
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  • Jennifer Dell'Elce BA,

    1. Prevention and Early Intervention Program for Psychoses, Douglas Mental Health University Institute, Verdun, Canada
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  • Katrina Messina BA,

    1. Prevention and Early Intervention Program for Psychoses, Douglas Mental Health University Institute, Verdun, Canada
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  • Martin Lepage PhD

    Corresponding author
    1. Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Canada
    2. Department of Psychiatry, McGill University, Montreal, Canada
    3. Prevention and Early Intervention Program for Psychoses, Douglas Mental Health University Institute, Verdun, Canada
    • Correspondence: Martin Lepage, PhD, Prevention and Early Intervention Program for Psychoses, Douglas Mental Health University Institute, 6875 LaSalle Blvd., Verdun, QC, Canada H4H 1R3. Email: martin.lepage@mcgill.ca

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Abstract

Aim

Previous research has linked cognitive insight (a measure of self-reflectiveness and self-certainty) in psychosis with neurocognitive and neuroanatomical disturbances in the fronto-hippocampal neural network. The authors’ goal was to use functional magnetic resonance imaging (fMRI) to investigate the neural correlates of cognitive insight during an external source memory paradigm in non-clinical subjects.

Methods

At encoding, 24 non-clinical subjects travelled through a virtual city where they came across 20 separate people, each paired with a unique object in a distinct location. fMRI data were then acquired while participants viewed images of the city, and completed source recognition memory judgments of where and with whom objects were seen, which is known to involve prefrontal cortex. Cognitive insight was assessed with the Beck Cognitive Insight Scale.

Results

External source memory was associated with neural activity in a widespread network consisting of frontal cortex, including ventrolateral prefrontal cortex (VLPFC), temporal and occipital cortices. Activation in VLPFC correlated with higher self-reflectiveness and activation in midbrain correlated with lower self-certainty during source memory attributions. Neither self-reflectiveness nor self-certainty significantly correlated with source memory accuracy.

Conclusion

By means of virtual reality and in the context of an external source memory paradigm, the study identified a preliminary functional neural basis for cognitive insight in the VLPFC in healthy people that accords with our fronto-hippocampal theoretical model as well as recent neuroimaging data in people with psychosis. The results may facilitate the understanding of the role of neural mechanisms in psychotic disorders associated with cognitive insight distortions.

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