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Entorhinal cortex

Clifford R Jack, Heather J Wiste, Christopher G Schwarz, Val J Lowe, Matthew L Senjem, Prashanthi Vemuri, Stephen D Weigand, Terry M Therneau, Dave S Knopman, Jeffrey L Gunter, David T Jones, Jonathan Graff-Radford, Kejal Kantarci, Rosebud O Roberts, Michelle M Mielke, Mary M Machulda, Ronald C Petersen
Our objective was to compare different whole-brain and region-specific measurements of within-person change on serial tau PET and evaluate its utility for clinical trials. We studied 126 individuals: 59 cognitively unimpaired with normal amyloid, 37 cognitively unimpaired with abnormal amyloid, and 30 cognitively impaired with an amnestic phenotype and abnormal amyloid. All had baseline amyloid PET and two tau PET, MRI, and clinical assessments. We compared the topography across all cortical regions of interest of tau PET accumulation rates and the rates of four different whole-brain or region-specific meta-regions of interest among the three clinical groups...
March 12, 2018: Brain: a Journal of Neurology
Niklas Wilming, Peter König, Seth König, Elizabeth A Buffalo
Grid cells in the entorhinal cortex allow for the precise decoding of position in space. Along with potentially playing an important role in navigation, grid cells have recently been hypothesized to make a general contribution to mental operations. A prerequisite for this hypothesis is that grid cell activity does not critically depend on physical movement. Here, we show that movement of covert attention, without any physical movement, also elicits spatial receptive fields with a triangular tiling of space...
March 14, 2018: ELife
Alan H Nagahara, Bayard R Wilson, Iryna Ivasyk, Imre Kovacs, Saytam Rawalji, John R Bringas, Phillip J Pivirotto, Waldy San Sebastian, Lluis Samaranch, Krystof S Bankiewicz, Mark H Tuszynski
Brain-derived neurotrophic factor (BDNF) gene delivery to the entorhinal cortex is a candidate for treatment of Alzheimer's disease (AD) to reduce neurodegeneration that is associated with memory loss. Accurate targeting of the entorhinal cortex in AD is complex due to the deep and atrophic state of this brain region. Using MRI-guided methods with convection-enhanced delivery, we were able to accurately and consistently target AAV2-BDNF delivery to the entorhinal cortex of non-human primates; 86 ± 3% of transduced cells in the targeted regions co-localized with the neuronal marker NeuN...
March 13, 2018: Gene Therapy
Li-Yuan Chen, Maxime Lévesque, Mauro Cataldi, Massimo Avoli
The muscarinic receptor agonist carbachol (CCh) can induce activity in the theta range (4 - 15 Hz) in the entorhinal cortex (EC), but the underlying network mechanisms remain unclear. Here, we investigated the interplay between interneurons and principal cells in the EC during CCh-induced theta-like field oscillations in an in vitro brain slice preparation using tetrodes. Field oscillations at 10.1 Hz (IQR = 9.5 - 10.9 Hz) occurred during bath application of CCh (100 μM; n = 32 experiments) and were associated with single-unit (n = 189) firing...
March 10, 2018: Neuroscience
Marta Gómez-Sancho, Jussi Tohka, Vanessa Gómez-Verdejo
Alzheimer's Disease (AD) is a progressive neurological disorder in which the death of brain cells causes memory loss and cognitive decline. The identification of at-risk subjects yet showing no dementia symptoms but who will later convert to AD can be crucial for the effective treatment of AD. For this, Magnetic Resonance Imaging (MRI) is expected to play a crucial role. During recent years, several Machine Learning (ML) approaches to AD-conversion prediction have been proposed using different types of MRI features...
March 9, 2018: Magnetic Resonance Imaging
Ariel A Batallán-Burrowes, C Andrew Chapman
Persistent firing in layer III entorhinal cortex neurons that can be evoked during muscarinic receptor activation may contribute to mechanisms of working memory. The entorhinal cortex receives strong dopaminergic inputs which may modulate working memory for motivationally significant information. We used whole cell recordings in in vitro rat brain slices to assess the effects of dopamine on persistent firing in layer III neurons initiated by depolarizing current injection. Persistent firing during pharmacological block of ionotropic excitatory and inhibitory synaptic transmission, and in the presence of the cholinergic agonist carbachol (10 μM), was observed in 39% of layer III pyramidal cells...
March 7, 2018: Neuroscience Letters
Rajapillai Li Pillai, Mengru Zhang, Jie Yang, J John Mann, Maria A Oquendo, Ramin V Parsey, Christine DeLorenzo
In most positron emission tomography (PET) molecular brain imaging studies, regions of interest have been defined anatomically and examined in isolation. However, by defining regions based on physiology and examining relationships between them, we may derive more sensitive measures of receptor abnormalities in conditions such as major depressive disorder (MDD). Using an average of 52 normalized binding potential maps, acquired using radiotracer [11 C]-WAY100635 and full arterial input analysis, we identified two molecular volumes of interest (VOIs) with contiguously high serotonin 1A receptor (5-HT1A ) binding sites: the olfactory sulcus (OLFS) and a band of tissue including piriform, olfactory, and entorhinal cortex (PRF)...
January 1, 2018: Journal of Cerebral Blood Flow and Metabolism
Zachariah M Reagh, Jessica A Noche, Nicholas J Tustison, Derek Delisle, Elizabeth A Murray, Michael A Yassa
The entorhinal cortex (EC) is among the earliest brain areas to deteriorate in Alzheimer's disease (AD). However, the extent to which functional properties of the EC are altered in the aging brain, even in the absence of clinical symptoms, is not understood. Recent human fMRI studies have identified a functional dissociation within the EC, similar to what is found in rodents. Here, we used high-resolution fMRI to identify a specific hypoactivity in the anterolateral EC (alEC) commensurate with major behavioral deficits on an object pattern separation task in asymptomatic older adults...
March 7, 2018: Neuron
Ling-Yun Fan, Ya-Mei Lai, Ta-Fu Chen, Yung-Chin Hsu, Pin-Yu Chen, Kuo-Zhou Huang, Ting-Wen Cheng, Wen-Yi Isaac Tseng, Mau-Sun Hua, Ya-Fang Chen, Ming-Jang Chiu
Alzheimer's disease (AD) progresses insidiously from the preclinical stage to dementia. While people with subjective cognitive decline (SCD) have normal cognitive performance, some may be in the preclinical stage of AD. Neurofibrillary tangles appear first in the transentorhinal cortex, followed by the entorhinal cortex in the clinically silent stage of AD. We expected the earliest changes in subjects with SCD to occur in medial temporal subfields other than the hippocampal proper. These selective structural changes would affect specific memory subcomponents...
March 8, 2018: Human Brain Mapping
Makiko Abe, Ken-Ichi Tabei, Masayuki Satoh, Mari Fukuda, Hironobu Daikuhara, Mariko Shiga, Hirotaka Kida, Hidekazu Tomimoto
Background/Aims: The missing fundamental phenomenon (MFP) is a universal pitch perception illusion that occurs in animals and humans. In this study, we aimed to determine whether the MFP is impaired in patients with Alzheimer's disease (AD) using an auditory pitch perception experiment. We further examined anatomical correlates of the MFP in patients with AD by measuring gray matter volume (GMV) on magnetic resonance images via voxel-based morphometric analysis. Methods: We prospectively enrolled 29 patients with AD and 20 healthy older adults...
January 2018: Dementia and Geriatric Cognitive Disorders Extra
Deirdre M O'Shea, Vonetta M Dotson, Adam J Woods, Eric C Porges, John B Williamson, Andrew O'Shea, Ronald Cohen
Objective: Research has shown that depression is a risk factor for Alzheimer's disease (AD) and subsequent cognitive decline. This is compounded by evidence showing an association between depression and reduced hippocampal volumes; a primary structure implicated in the pathogenesis of the disease. Less is known about the relationship between depression and other AD vulnerable regions such as the entorhinal cortex. Given the heterogeneity of depressive symptom presentation, we examined whether symptom dimensions were associated with hippocampal and entorhinal cortex volumes in community dwelling older adults...
2018: Frontiers in Aging Neuroscience
Ines Mahjoub, Mohamed Ali Mahjoub, Islem Rekik
Accurate diagnosis of mild cognitive impairment (MCI) before conversion to Alzheimer's disease (AD) is invaluable for patient treatment. Many works showed that MCI and AD affect functional and structural connections between brain regions as well as the shape of cortical regions. However, 'shape connections' between brain regions are rarely investigated -e.g., how morphological attributes such as cortical thickness and sulcal depth of a specific brain region change in relation to morphological attributes in other regions...
March 7, 2018: Scientific Reports
Simon Jonas Enkirch, Andreas Traschütz, Andreas Müller, Catherine N Widmann, Gerrit H Gielen, Michael T Heneka, Alina Jurcoane, Hans H Schild, Elke Hattingen
Purpose To establish and evaluate a visual score focused on entorhinal cortex atrophy (ERICA), as the entorhinal cortex is one of the first brain structures affected in Alzheimer disease (AD). Materials and Methods In this retrospective study, ERICA was visually evaluated with magnetic resonance imaging (2009-2016). First, a four-point ERICA score was developed by using data in 48 consecutive subjects (20 patients with AD and 28 control subjects). Then, in the main analysis, ERICA and the standard medial temporal lobe atrophy (MTA) scores were determined in an independent cohort of 60 patients suspected of having AD (mean age, 69...
March 7, 2018: Radiology
Robert Naumann, Patricia Preston-Ferrer, Michael Brecht, Andrea Burgalossi
Following the groundbreaking discovery of grid cells, the medial entorhinal cortex (MEC) has become the focus of intense anatomical, physiological, and computational investigations. Whether and how grid activity maps onto cell types and cortical architecture is still an open question. Fundamental similarities in microcircuits, function and connectivity suggest a homology between rodent MEC and human posteromedial entorhinal cortex. Both are specialized for spatial processing and display similar cellular organization, consisting of layer 2 pyramidal/calbindin cell patches superimposed on scattered stellate neurons...
March 7, 2018: Journal of Neurophysiology
Yang Yang, Wei-Gang Ji, Zhi-Ru Zhu, Yu-Ling Wu, Zhi-Yang Zhang, Shao-Chen Qu
Rhynchophylline (RIN) is a significant active component isolated from the Chinese herbal medicine Uncaria rhynchophylla. The overproduction of soluble amyloid β protein (Aβ) oligomers in the hippocampus is closely involved in impairments in cognitive function at the early stage of Alzheimer's disease (AD). Growing evidences show that RIN possesses neuroprotective effects against Aβ-induced neurotoxicity. However, whether RIN can prevent soluble Aβ1-42 -induced impairments in spatial cognitive function and synaptic plasticity is still unclear...
March 3, 2018: Neuropharmacology
Sandra Guidi, Andrea Giacomini, Fiorenza Stagni, Marco Emili, Beatrice Uguagliati, Maria Paola Bonasoni, Renata Bartesaghi
Down syndrome (DS) is a genetic condition associated with impairment in several cognitive domains. Previous evidence showed a notable neurogenesis reduction in the hippocampal region of DS fetuses, which may account for the impairment of declarative memory that characterizes DS starting from early life stages. The fusiform gyrus (FG) and the inferior temporal gyrus (ITG) play a key role in visual recognition memory, a function that is impaired in children and adults with DS. The goal of the current study was to establish whether fetuses with DS (17-21 weeks of gestation) exhibit neuroanatomical alterations in the FG and ITG that may underlie recognition memory impairment...
March 6, 2018: Brain Pathology
P A Zykin, I A Moiseenko, L A Tkachenko, R A Nasyrov, E A Tsvetkov, E I Krasnoshchekova
We studied peculiarities of the structure of human entorhinal cortex at weeks 20-26 of gestation (10 hemispheres). The samples were Nissl-stained and immunohistochemically treated with antibodies to parvalbumin, calretinin, calbindin, and cytoskeleton proteins (MAP2 and N200). 3D-reconstruction of the entorhinal cortex from serial sections was performed, caudomedial and rostrolateral areas were isolated. Parvalbumin+ cells in layer I, discrete distribution of layer II cells with colocalization of MAP2 and calretinin at the border with layer I, and two sublayers Va and Vb with MAP2+ neurons were typical for the caudomedial area...
March 4, 2018: Bulletin of Experimental Biology and Medicine
Printha Wijesinghe, Catherine Gorrie, S K Shankar, Yasha T Chickabasaviah, Dhammika Amaratunga, Sanjayah Hulathduwa, K Sunil Kumara, Kamani Samarasinghe, Yoo-Hun Suh, H W M Steinbusch, K Ranil D De Silva
Background: There is little information available in the literature concerning the contribution of dementia in injury deaths in elderly people (≥60 years). Aim: This study was intended to investigate the extent of dementia-related pathologies in the brains of elderly people who died in traffic accidents or by suicide and to compare our findings with age- and sex-matched natural deaths in an elderly population. Materials and Methods: Autopsy-derived human brain samples from nine injury death victims (5 suicide and 4 traffic accidents) and nine age- and sex-matched natural death victims were screened for neurodegenerative and cerebrovascular pathologies using histopathological and immunohistochemical techniques...
October 2017: Indian Journal of Psychiatry
Seong Gak Jeon, Yong Jun Kim, Kyoung Ah Kim, Inhee Mook-Jung, Minho Moon
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and neurodegeneration in the hippocampus. Despite the pathological importance of the hippocampal degeneration in AD, little topographical evidence exists of impaired hippocampal connectivity in patients with AD. To investigate the anatomical connections of the hippocampus, we injected the neurotracer 1,1'-dioctadecyl-3,3,3'3,3'-tetramethyl-indocarbocyanine perchlorate (DiI) into the hippocampi of 5XFAD mice, which were used as an animal model of AD...
February 27, 2018: Molecular Neurobiology
Heather Nichol, Bénédicte Amilhon, Frédéric Manseau, Saishree Badrinarayanan, Sylvain Williams
The nicotinic acetylcholine receptor alpha2 subunit (Chrna2) is a specific marker for oriens lacunosum-moleculare (OLM) interneurons in the dorsal CA1 region of the hippocampus. It was recently shown using a Chrna2-cre mice line that OLM interneurons can modulate entorhinal cortex and CA3 inputs and may therefore have an important role in gating, encoding, and recall of memory. In this study, we have used a combination of electrophysiology and optogenetics using Chrna2-cre mice to determine the role of Chrna2 interneurons in the subiculum area, the main output region of the hippocampus...
2018: Frontiers in Cellular Neuroscience
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