The network substrate of confabulatory tendencies in Alzheimer's disease

Venneri, Annalena; Mitolo, Micaela; Marco, Matteo De

doi:10.1016/j.cortex.2016.08.015

Cited by 8 publications

(13 citation statements)

References 40 publications

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“…These results seem to suggest that confabulations are not directly related to damage of a single brain area, but rather have a complex neuroanatomical origin. This is in line with recent studies which have linked the confabulation tendency in AD patients to the impairment of complex circuits between different hubs, particularly between the right prefrontal cortex and the mediotemporal regions involved in memory retrieval (Venneri et al, 2017).…”

Section: Discussionsupporting

confidence: 92%

“…A decreased connectivity between the posterior (precuneus and posterior cingulate cortex) and anterior (anterior cingulate cortex and medial prefrontal cortex) regions of the DMN has been already associated with AD (Mohan et al, 2016). According to recent evidences, the insufficient suppression of the DMN during cognitive tasks is responsible for the inability to distinguish accurate information from the irrelevant ones during the process of memory retrieval, thus contributing to generate confabulations (Venneri et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

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Confabulations in Cases of Dementia: Atypical Early Sign of Alzheimer’s Disease or Misleading Feature in Dementia Diagnosis?

et al. 2020

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Confabulations, also known as false memories, have been associated with various diseases involving mainly the frontal areas, such as Wernicke-Korsakoff syndrome or frontal epilepsy. The neuropsychological dysfunctions underlying mechanisms of confabulation are not well known. We describe two patients with memory impairment and confabulations at the onset speculating about neuropsychological correlates of confabulations and self-awareness. Both patients, a 77-year-old woman and a 57years-old man, exhibited confabulations as first symptom of cognitive decline. She later developed memory impairment without awareness of her memory deficits and her cognitive and imaging profile suggested an amnesic mild cognitive impairment due to Alzheimer's disease (AD). Unlike her, he developed a prevalent involvement of frontal functions despite a clear consciousness of his cognitive deficits. However, the clinical diagnostic hypothesis of behavioral variant of frontotemporal dementia was not supported by imaging findings, which suggested AD. Both patients underwent neuropsychological evaluation including the Confabulation Battery. Despite that the exact anatomical correlation of confabulations is still not defined, imaging data shown by our patients is consistent with recent theories according to which at the origin of confabulatory tendency in AD there is an impairment of the connections between crucial hubs in frontal and mediotemporal areas, mainly involving the right hemisphere. Besides, it would be reasonable to hypothesize that self-awareness and confabulations should not be considered as necessarily associated dimensions.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Confabulations in Cases of Dementia: Atypical Early Sign of Alzheimer’s Disease or Misleading Feature in Dementia Diagnosis?

et al. 2020

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“…Each of the three remaining identified studies employed a different functional neuroimaging technique including connectivity analysis using resting-state functional MRI (fMRI) (Venneri et al, 2017), positron emission tomography (PET) using the 18 Ffluoro-2-deoxyglucose ( 18 FDG) tracer (Desgranges et al, 2002) and single photon emission computed tomography (SPECT) using the 123 I N -isopropyl-p-iodoamphetamine (IMP) tracer (Reed et al, 1993).…”

Section: Characteristics Of Included Studiesmentioning

confidence: 99%

“…Data for the fMRI connectivity analysis conducted by Venneri et al (2017) were acquired at two different sites. In Italy, 18 participants had two resting-state fMRI echoplanar sequences (voxel dimensions 3.28x3.28x6.0mm) and a complementary 3D anatomical T1-weighted scan (1.1x1.1x6mm voxels) acquired on a 1.5T scanner.…”

Section: Fmri Connectivity Analysismentioning

confidence: 99%

Neuroimaging correlates of false memory in 'Alzheimer's disease: A preliminary systematic review

McLachlan

Rai

Al-Shihabi

et al. 2020

Psychiatry Research: Neuroimaging

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Alzheimer's disease (AD) is characterised by episodic memory impairment, but people also experience memory distortions, including false memories, which can impact on safety and reduce functioning. Understanding the neural networks that underpin false memories could help to predict the need for intervention and guide development of cognitive strategies to reduce memory errors. However, there is a relative absence of research into how the neuropathology of AD contributes to false memory generation. This paper systematically reviews the methodology and outcomes of studies investigating the neuroimaging correlates of false memory in AD. Four studies using structural imaging and three studies using functional imaging were identified. Studies were heterogenous in methodology and received mostly 'weak' quality assessment ratings. Combined, and consistent with neuroimaging findings in non-AD populations,

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“…The confabulator, by definition, does not have a pre-simulated story that could indicate the ability of the LPFC to ascertain control over the posterior cortex. Confabulatory tendencies are often interpreted as an indicator of a disconnection between PFC and the posterior cortex 121 . 5) Many people report the experience of reading aloud a book to a child and thinking of something else.…”

Section: Is There a Neurological Dissociation Between Language And Comentioning

confidence: 99%

Linguistically deprived children: meta-analysis of published research underlines the importance of early syntactic language use for normal brain development

Vyshedskiy

Mahapatra²,

Dunn³

2017

Preprint

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We analyzed all published reports of individuals not exposed to syntactic language until puberty: two feral children, who grew up without hearing any language, and eight deaf linguistic isolates, who grew up communicating to their families using homesign or kitchensign, a system of gestures which allows them to communicate simple commands but lacks much in the way of syntax. A common observation in these individuals is the lifelong difficulty understanding syntax and spatial prepositions, even after many years of rehabilitation. This debilitating condition stands in stark contrast to linguistic isolates' performance on memory as well as semantic tests: they could easily remember hundreds of newly learned words and identify previously seen objects by name. The lack of syntactic language comprehension in linguistic isolates may stem from inability to understand words and/or grammar or inability to mentally synthesize known objects into novel configurations. We have previously shown that purposeful construction of novel mental images is the function of the lateral prefrontal cortex (LPFC) ability to dynamically control posterior cortex neurons 1 . Here we have ranked all tests performed on linguistic isolates by their reliance on the LPFC control of the posterior cortex: a) the amount of posterior cortex territory that needs to be recruited by the LPFC and b) the number of disparate objects that have to be combined together by the LPFC in order to answer the test question. According to our analysis, linguistic isolates performed well in all tests that did not involve the LPFC control of the posterior cortex, showed decreasing scores in tests that involved greater recruitment of the posterior cortex by the LPFC, and failed in tests that involved greatest recruitment of posterior cortex necessary for mental synthesis of multiple objects. This pattern is consistent with inadequate frontoposterior connections in linguistic isolates. We discuss implications of these findings for the importance of early syntactic language exposure in formation of frontoposterior connections. Abbreviations:NOB score = number of objects score PCT score = posterior cortex territory score peer-reviewed)

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The network substrate of confabulatory tendencies in Alzheimer's disease

Cited by 8 publications

References 40 publications

Confabulations in Cases of Dementia: Atypical Early Sign of Alzheimer’s Disease or Misleading Feature in Dementia Diagnosis?

Confabulations in Cases of Dementia: Atypical Early Sign of Alzheimer’s Disease or Misleading Feature in Dementia Diagnosis?

Neuroimaging correlates of false memory in 'Alzheimer's disease: A preliminary systematic review

Linguistically deprived children: meta-analysis of published research underlines the importance of early syntactic language use for normal brain development

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