Self-awareness and the medial temporal lobe in neurodegenerative diseases

Chavoix, Chantal; Insausti, Ricardo

doi:10.1016/j.neubiorev.2017.04.015

Cited by 41 publications

(43 citation statements)

References 99 publications

(159 reference statements)

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“…The middle temporal pole was the only region of the participants with increased activation after MBCT treatment. This is a brain region dedicated to social cognition (van der Cruijsen, Peters, & Crone, ), involving both self‐awareness (Chavoix & Insausti, ) and autobiographical memory (Dupont, ). Also, this brain region is associated with mental state awareness of both self and others (Berthoz, Armony, Blair, & Dolan, ; Fletcher et al, ; Gallagher et al, ; Saxe & Powell, ; Vogeley et al, ).…”

Section: Discussionmentioning

confidence: 99%

Mindfulness‐based cognitive therapy is associated with distinct resting‐state neural patterns in patients with generalized anxiety disorder

Zhao

Chen

Kang

et al. 2019

Asia-Pacific Psychiatry

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Introduction: Mindfulness-based cognitive therapy (MBCT) may be effective for generalized anxiety disorder (GAD); however, the neural mechanism is poorly understood. In this study, we examined the potential neural mechanisms through which MBCT may reduce anxiety in patients with mild-to-moderate GAD.Methods: Eight weekly group MBCT sessions (2 h each) were conducted with 32 GAD patients. Resting-state functional magnetic resonance imaging (fMRI) was used, along with clinical and mindfulness profiles. A regional homogeneity (ReHo) approach was applied, and resting-state functional connectivity in the default mode network (DMN) using the posterior cingulate cortex (PCC) seed was examined.Results: MBCT reduced the anxiety and increased the mindfulness abilities of patients. After MBCT, patients had reduced ReHo in broad regions of the limbic system, along with increased DMN functional connectivity in the anterior cingulate cortex (ACC) and bilateral insula. Overlapping regions of reduced ReHo and increased DMN functional connectivity were observed in the mid-cingulate cortex (MCC) and bilateral insula. The increased PCC-ACC and PCC-insula functional connectivity following MBCT were related to anxiety improvements, suggesting a potential therapeutic mechanism for mindfulness-based therapies. Discussion: Group MBCT treatment appears to have effectively reduced anxiety symptoms in patients with mild-to-moderate GAD. Activation and functional connectivity appeared significantly different across some limbic regions after MBCT treatment. The salience network showed reduced ReHo and increased connectivity to the PCC. The DMN functional connectivity of the MCC may indicate reduced anxiety and improved mindfulness in GAD patients. K E Y W O R D S functional MRI (fMRI), generalized anxiety disorder, mindfulness-based cognitive therapy (MBCT), waiting list

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Section: Discussionmentioning

confidence: 99%

Mindfulness‐based cognitive therapy is associated with distinct resting‐state neural patterns in patients with generalized anxiety disorder

Zhao

Chen

Kang

et al. 2019

Asia-Pacific Psychiatry

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“…Outliers in the global mean signal intensity and motion were subsequently included as nuisance regressors during the functional analysis. We chose a strategic node of the MT subsystem of the DMN as a seed (Chavoix & Insausti, 2017).…”

Section: Data Processingmentioning

confidence: 99%

Anosognosia and default mode subnetwork dysfunction in Alzheimer's disease

Antoine

Bahri

Bastin

et al. 2019

Human Brain Mapping

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Research on the neural correlates of anosognosia in Alzheimer's disease varied according to methods and objectives: they compared different measures, used diverse neuroimaging modalities, explored connectivity between brain networks, addressed the role of specific brain regions or tried to give support to theoretical models of unawareness. We used resting‐state fMRI connectivity with two different seed regions and two measures of anosognosia in different patient samples to investigate consistent modifications of default mode subnetworks and we aligned the results with the Cognitive Awareness Model. In a first study, patients and their relatives were presented with the Memory Awareness Rating Scale. Anosognosia was measured as a patient‐relative discrepancy score and connectivity was investigated with a parahippocampal seed. In a second study, anosognosia was measured in patients with brain amyloid (taken as a disease biomarker) by comparing self‐reported rating with memory performance, and connectivity was examined with a hippocampal seed. In both studies, anosognosia was consistently related to disconnection within the medial temporal subsystem of the default mode network, subserving episodic memory processes. Importantly, scores were also related to disconnection between the medial temporal and both the core subsystem (participating to self‐reflection) and the dorsomedial subsystem of the default mode network (the middle temporal gyrus that might subserve a personal database in the second study). We suggest that disparity in connectivity within and between subsystems of the default mode network may reflect impaired functioning of pathways in cognitive models of awareness.

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“…In neurodegenerative diseases (i.e. AD, frontotemporal dementia, Parkinson’s disease, Huntington’s disease, MCI and amyotrophic lateral sclerosis), impaired self-awareness has been linked to structural and functional neuroimaging abnormalities in the hippocampus, amygdala and temporopolar, entorhinal, perirhinal and posterior parahippocampal cortices (Chavoix & Insausti, 2017 ). In dementia patients, the neuroanatomical correspondents of unawareness are the frontal, medial parietal and lateral parietotemporal regions.…”

Section: Introductionmentioning

confidence: 99%

“…Alterations in cortical midline structures and default mode network intrinsic brain activity among AD patients have provided insight into the processing of self-related information (Weiler, Northoff, Damasceno, & Balthazar, 2016 ). Neuropathological, structural and functional changes in the medial temporal lobe have been found in patients with different neurodegenerative diseases who overestimate their performance in cognitive, socioemotional, or daily life activities (Chavoix & Insausti, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

Functional Neural Correlates of Anosognosia in Mild Cognitive Impairment and Alzheimer’s Disease: a Systematic Review

2019

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Functional neuroimaging techniques (i.e. single photon emission computed tomography, positron emission tomography, and functional magnetic resonance imaging) have been used to assess the neural correlates of anosognosia in mild cognitive impairment (MCI) and Alzheimer’s disease (AD). A systematic review of this literature was performed, following the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement, on PubMed, EMBASE, and PsycINFO databases. Twenty-five articles met all inclusion criteria. Specifically, four brain connectivity and 21 brain perfusion, metabolism, and activation articles. Anosognosia is associated in MCI with frontal lobe and cortical midline regional dysfunction (reduced perfusion and activation), and with reduced parietotemporal metabolism. Reduced within and between network connectivity is observed in the default mode network regions of AD patients with anosognosia compared to AD patients without anosognosia and controls. During initial stages of cognitive decline in anosognosia, reduced indirect neural activity (i.e. perfusion, metabolism, and activation) is associated with the cortical midline regions, followed by the parietotemporal structures in later stages and culminating in frontotemporal dysfunction. Although the current evidence suggests differences in activation between AD or MCI patients with anosognosia and healthy controls, more evidence is needed exploring the differences between MCI and AD patients with and without anosognosia using resting state and task related paradigms. Electronic supplementary material The online version of this article (10.1007/s11065-019-09410-x) contains supplementary material, which is available to authorized users.

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Self-awareness and the medial temporal lobe in neurodegenerative diseases

Cited by 41 publications

References 99 publications

Mindfulness‐based cognitive therapy is associated with distinct resting‐state neural patterns in patients with generalized anxiety disorder

Mindfulness‐based cognitive therapy is associated with distinct resting‐state neural patterns in patients with generalized anxiety disorder

Anosognosia and default mode subnetwork dysfunction in Alzheimer's disease

Functional Neural Correlates of Anosognosia in Mild Cognitive Impairment and Alzheimer’s Disease: a Systematic Review

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