Cognitive dysfunction in major depression and Alzheimer&amp;#39;s disease is associated with hippocampus&amp;ndash;prefrontal cortex dysconnectivity

Sampath, Dayalan; Sathyanesan, Monica; Newton, Samuel S.

doi:10.2147/ndt.s136122

Cited by 104 publications

(79 citation statements)

References 129 publications

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“…Therefore, this abnormal connectivity may give rise to memory loss and negative emotions in patients with MDD. Finally, with the subiculum seed region, increased functional connectivity with the right MFG was found and this finding is consistent with previous research [56]. The right MFG plays a very important role in attention as the point of convergence between the dorsolateral prefrontal cortex and the ventrolateral prefrontal cortex [27].…”

Section: Discussionsupporting

confidence: 91%

Abnormal resting-state functional connectivity of hippocampal subfields in patients with major depressive disorder

Hao

Zhong

et al. 2020

BMC Psychiatry

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Background: Many studies have found that the hippocampus plays a very important role in major depressive disorder (MDD). The hippocampus can be divided into three subfields: the cornu ammonis (CA), dentate gyrus (DG) and subiculum. Each subfield of the hippocampus has a unique function and are differentially associated with the pathological mechanisms of MDD. However, no research exists to describe the resting state functional connectivity of each hippocampal subfield in MDD. Methods: Fifty-five patients with MDD and 25 healthy controls (HCs) matched for gender, age and years of education were obtained. A seed-based method that imposed a template on the whole brain was used to assess the resting-state functional connectivity (rsFC) of each hippocampal subfield.Results: Patients with MDD demonstrated increased connectivity in the left premotor cortex (PMC) and reduced connectivity in the right insula with the CA seed region. Increased connectivity was reported in the left orbitofrontal cortex (OFC) and left ventrolateral prefrontal cortex (vlPFC) with the DG seed region. The subiculum seed region revealed increased connectivity with the left premotor cortex (PMC), the right middle frontal gyrus (MFG), the left ventrolateral prefrontal cortex (vlPFC) and reduced connectivity with the right insula. ROC curves confirmed that the differences between groups were statistically significant. Conclusion: The results suggest that the CA, DG and subiculum have significant involvement with MDD. Specifically, the abnormal functional connectivity of the CA may be related to bias of coding and integration of information in patients with MDD. The abnormal functional connectivity of the DG may be related to the impairment of working memory in patients with MDD, and the abnormal functional connectivity of the subiculum may be related to cognitive impairment and negative emotions in patients with MDD.

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Section: Discussionsupporting

confidence: 91%

Abnormal resting-state functional connectivity of hippocampal subfields in patients with major depressive disorder

Hao

Zhong

et al. 2020

BMC Psychiatry

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“…Since the prefrontal cortex plays a key role in working memory and in decision making processes [38,39], the dorsal hippocampus is involved in spatial processing, and the ventral hippocampus is more related to emotional behavior [40,41], it is feasible that the increase of Bdnf following C. asiatica L. administration may contribute to the amelioration of working memory processes. Moreover, previous results of our group [14] suggested that several molecular pathways are activated during the task and that this activation may be responsible and/or contribute to the improvement of the performance.…”

Section: Discussionmentioning

confidence: 99%

Centella asiatica L. Phytosome Improves Cognitive Performance by Promoting Bdnf Expression in Rat Prefrontal Cortex

et al. 2020

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A wide range of people in the world use natural remedies as primary approaches against illnesses. Accordingly, understanding the mechanisms of action of phytochemicals has become of great interest. In this context, Centella asiatica L. is extensively used, not only as anti-inflammatory or antioxidant agent but also as brain tonic. On this basis, the purpose of this study was to evaluate whether the chronic administration of C. asiatica L. to adult male rats was able to improve the expression of Bdnf, one of the main mediators of brain plasticity. Moreover, we assessed whether the treatment could affect the cognitive performance in the novel object recognition (NOR) test. We confirmed the presence of the main compounds in the plasma. Furthermore, C. asiatica L. administration induced an increase of Bdnf in the prefrontal cortex, and the administration of the higher dose of the extract was able to improve cognitive performance. Finally, the increase in the preference index in the NOR test was paralleled by a further increase in Bdnf expression. Overall, we highlight the ability of C. asiatica L. to affect brain functions by increasing Bdnf expression and by enhancing the cognitive performance.

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“…Its inclusion of AD, MCI, and CN patients suggests that it may represent baseline age-related cognitive decline. Other studies of this same patient database have identified the clustered changes in Phenotype 4 as belonging specifically to Alzheimer's patients 25 . Structural degeneration of the clustered areas results in damage to the hippocampal-prefrontal cortex pathway which was also found in other studies of AD patients.…”

Section: Discussionmentioning

confidence: 99%

Multimodal Phenotyping of Alzheimer’s Disease with Longitudinal Magnetic Resonance Imaging and Cognitive Function Data

Kim

Jiang

Giancardo

et al. 2020

Sci Rep

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's Disease neuroimaging initiative † Alzheimer's disease (AD) varies a great deal cognitively regarding symptoms, test findings, the rate of progression, and neuroradiologically in terms of atrophy on magnetic resonance imaging (MRi). We hypothesized that an unbiased analysis of the progression of AD, regarding clinical and MRi features, will reveal a number of AD phenotypes. our objective is to develop and use a computational method for multi-modal analysis of changes in cognitive scores and MRi volumes to test for there being multiple AD phenotypes. In this retrospective cohort study with a total of 857 subjects from the AD (n = 213), Mci (n = 322), and control (CN, n = 322) groups, we used structural MRI data and neuropsychological assessments to develop a novel computational phenotyping method that groups brain regions from MRi and subsets of neuropsychological assessments in a non-biased fashion. the phenotyping method was built based on coupled nonnegative matrix factorization (c-nMf). As a result, the computational phenotyping method found four phenotypes with different combination and progression of neuropsychologic and neuroradiologic features. identifying distinct AD phenotypes here could help explain why only a subset of AD patients typically respond to any single treatment. this, in turn, will help us target treatments more specifically to certain responsive phenotypes. Alzheimer's disease (AD) is the most common form of dementia. It is a progressive neurodegenerative disorder associated with cognitive decline and atrophy seen on Magnetic Resonance Imaging (MRI) of the brain 1. It has become a major public health concern because of its increasing prevalence, chronicity, caregiver burden, and high personal and financial costs of care 2. AD is clinically very heterogeneous, varying between patients in terms of cognitive symptoms, test findings, and rates of progression 3. It also varies neuroradiologically in terms of atrophy on MRI Memory deficits, caused by pathological changes in structures of the medial temporal lobe 4,5 , are typically regarded as the earliest and most salient symptom of AD 6,7 , but this is not invariably the case 8. Instead, patients may present with visuospatial or language disturbance, or apraxia 9 , likely reflecting regional differences in the underlying neuropathology 8,10-12. It can also present as a single area of cognitive impairment without a change in activities of daily living, in which case this prodromal AD is referred to as mild cognitive impairment, or MCI. Several recent treatment trials for AD have shown efficacy in a subset of patients, but not all patients. We hypothesize that there are subsets of AD patients who respond differently to treatments. Furthermore, we

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Cognitive dysfunction in major depression and Alzheimer's disease is associated with hippocampus–prefrontal cortex dysconnectivity

Cited by 104 publications

References 129 publications

Abnormal resting-state functional connectivity of hippocampal subfields in patients with major depressive disorder

Abnormal resting-state functional connectivity of hippocampal subfields in patients with major depressive disorder

Centella asiatica L. Phytosome Improves Cognitive Performance by Promoting Bdnf Expression in Rat Prefrontal Cortex

Multimodal Phenotyping of Alzheimer’s Disease with Longitudinal Magnetic Resonance Imaging and Cognitive Function Data

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