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contextual memory

Caroline Morel, Tessi Sherrin, Norman J Kennedy, Kelly H Forest, Seda Avcioglu Barutcu, Michael Robles, Ezekiel Carpenter-Hyland, Naghum Alfulaij, Claire L Standen, Robert A Nichols, Morris Benveniste, Roger J Davis, Cedomir Todorovic
The c-Jun N-terminal kinase (JNK) signal transduction pathway is implicated in learning and memory. Here, we examined the role of JNK activation mediated by the JIP1 scaffold protein. We compared male wild-type mice with a mouse model harboring a point mutation in the Jip1 gene that selectively blocks JIP1-mediated JNK activation. These male mutant mice exhibited increased NMDA receptor currents, increased NMDA receptor-mediated gene expression, and a lower threshold for induction of hippocampal long-term potentiation...
March 14, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Andrés Pomi
BACKGROUND: One of the central challenges of third millennium medicine is the abatement of medical errors. Among the most frequent and hardiest causes of misdiagnosis are cognitive errors produced by faulty medical reasoning. These errors have been analyzed from the perspectives of cognitive psychology and empirical medical studies. We introduce a neurocognitive model of medical diagnosis to address this issue. METHODS: We construct a connectionist model based on the associative nature of human memory to explore the non-analytical, pattern-recognition mode of diagnosis...
November 27, 2017: Diagnosis
Lâle Battal Merlet, Alain Blanchet, Hazlin Lockman, Milena Kostova
The objective of this electrophysiological study was to investigate the processing of semantic coherence during encoding in relation to episodic memory processes promoted at test, in schizophrenia patients, by using the N400 paradigm. Eighteen schizophrenia patients and 15 healthy participants undertook a recognition memory task. The stimuli consisted of pairs of words either semantically related or unrelated to a given category name (context). During encoding, both groups exhibited an N400 external semantic coherence effect...
2018: Schizophrenia Research and Treatment
Eunyoung Bang, Boyoung Lee, Joon-Oh Park, Yooncheol Jang, Aekyong Kim, Sungwuk Kim, Hee-Sup Shin
In recent years, as the aging population grows, aging-induced cognitive impairments including dementia and Alzheimer's disease (AD) have become the biggest challenges for global public health and social care. Therefore, the development of potential therapeutic drugs for aging-associated cognitive impairment is essential. Metabolic dysregulation has been considered to be a key factor that affects aging and dementia. Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a primary sensor of cellular energy states and regulates cellular energy metabolism...
February 2018: Experimental Neurobiology
Shingo Matsuda, Daisuke Matsuzawa, Daisuke Ishii, Haruna Tomizawa, Eiji Shimizu
Onset of fear-related disorders such as post-traumatic stress disorder is enhanced from adolescence until adulthood. However, the biological mechanisms underlying this vulnerability remain unclear. Therefore, we investigated contextual fear memory and extinction in 4-, 6-, 8-, 10-, and 15-week-old female mice. We also measured phosphorylation of ERK2 in the medial prefrontal cortex (mPFC) and the dorsal hippocampus in the mPFC following fear conditioning or extinction in 6- and 15-week-old mice. We found that 10- and 15-week-old mice showed stronger fear memory and more resistance to fear extinction than 6-week-old mice...
March 10, 2018: Neurobiology of Learning and Memory
Nannan Guo, Marta E Soden, Charlotte Herber, Michael TaeWoo Kim, Antoine Besnard, Paoyan Lin, Xiang Ma, Constance L Cepko, Larry S Zweifel, Amar Sahay
Memories become less precise and generalized over time as memory traces reorganize in hippocampal-cortical networks. Increased time-dependent loss of memory precision is characterized by an overgeneralization of fear in individuals with post-traumatic stress disorder (PTSD) or age-related cognitive impairments. In the hippocampal dentate gyrus (DG), memories are thought to be encoded by so-called 'engram-bearing' dentate granule cells (eDGCs). Here we show, using rodents, that contextual fear conditioning increases connectivity between eDGCs and inhibitory interneurons (INs) in the downstream hippocampal CA3 region...
March 12, 2018: Nature Medicine
Masaya Misaki, Raquel Phillips, Vadim Zotev, Chung-Ki Wong, Brent E Wurfel, Frank Krueger, Matthew Feldner, Jerzy Bodurka
Altered resting-state functional connectivity in posttraumatic stress disorder (PTSD) suggests neuropathology of the disorder. While seed-based fMRI connectivity analysis is often used for the studies, such analysis requires defining a seed location a priori , which restricts search scope and could bias findings toward presupposed areas. Recently, a comprehensive exploratory voxel-wise connectivity analysis, the connectome-wide association approach, has been introduced using multivariate distance matrix regression (MDMR) for resting-state functional connectivity analysis...
2018: NeuroImage: Clinical
Xuqian Chen, Wei Yang, Lijun Ma, Jiaxin Li
Recent findings have shown that information about changes in an object's environmental location in the context of discourse is stored in working memory during sentence comprehension. However, in these studies, changes in the object's location were always consistent with world knowledge (e.g., in "The writer picked up the pen from the floor and moved it to the desk," the floor and the desk are both common locations for a pen). How do people accomplish comprehension when the object-location information in working memory is inconsistent with world knowledge (e...
2018: Frontiers in Psychology
Mirelle A Casagrande, Josué Haubrich, Lizeth K Pedraza, Bruno Popik, Jorge A Quillfeldt, Lucas de Oliveira Alvares
Memories are not instantly created in the brain, requiring a gradual stabilization process called consolidation to be stored and persist in a long-lasting manner. However, little is known whether this time-dependent process is dynamic or static, and the factors that might modulate it. Here, we hypothesized that the time-course of consolidation could be affected by specific learning parameters, changing the time window where memory is susceptible to retroactive interference. In the rodent contextual fear conditioning paradigm, we compared weak and strong training protocols and found that in the latter memory is susceptible to post-training hippocampal inactivation for a shorter period of time...
March 5, 2018: Neurobiology of Learning and Memory
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
Ana Paula Crestani, Rodrigo Ordoñez Sierra, Adriano Machado, Josué Haubrich, Krislei Martin Scienza, Lucas de Oliveira Alvares, Jorge Alberto Quillfeldt
The requirement of NMDA receptor (NMDAR) activity for memory formation is well described. However, the plasticity mechanisms for memory can be modified by experience, such that a future similar learning becomes independent of NMDARs. This effect has often been reported in learning events conducted with a few days interval. In this work, we asked whether the NMDAR-independency is permanent or the brain regions and plasticity mechanisms of experience-dependent learning may change over time. Considering that contextual memories undergo a gradual reorganization over time, becoming progressively independent from the hippocampus and dependent upon cortical regions, we investigated the brain regions mediating a new related learning conducted at a remote time-point, when the first memory was already cortically established...
February 28, 2018: Neurobiology of Learning and Memory
Linda Marschner, An Schreurs, Benoit Lechat, Jesper Mogensen, Anton Roebroek, Tariq Ahmed, Detlef Balschun
Mild traumatic brain injury (mTBI) can lead to diffuse neurophysical damage as well as cognitive and affective alterations. The nature and extent of behavioral changes after mTBI are still poorly understood and how strong an impact force has to be to cause long-term behavioral changes is not yet known. Here, we examined spatial learning acquisition, retention and reversal in a Morris water maze, and assessed search strategies during task performance after a single, mild, closed-skull traumatic impact referred to as "minimal" TBI...
February 27, 2018: Behavioural Brain Research
Felipe Vanz, Maíra Assunção Bicca, Vagner Fagnani Linartevichi, Marcelo Giachero, Leandro José Bertoglio, Thereza C Monteiro de Lima
The main κ opioid receptors (κORs) subtypes already described (κ1 ORs and κ2 ORs) are expressed in brain regions involved in aversive memory consolidation, including the dorsal hippocampus (DH). However, the role of DH κORs in consolidation of aversive memories with varied intensity and specificity is still uncertain. The present study aimed to investigate this question using pharmacological agents in rats subjected to a weak, moderate or strong contextual aversive conditioning (CAC) protocol. Antagonizing DH κORs with nor-binaltorphimine (nor-BNI), immediately after, but not 6 h later, a moderate CAC leads to intensified freezing behavior in the re-exposure to the paired context...
February 27, 2018: Neuropharmacology
Karsten Baumgärtel, Andrea Green, Diana Hornberger, Jennifer Lapira, Christopher Rex, Damian G Wheeler, Marco Peters
The retrosplenial cortex (RSC) plays a critical role in episodic memory, but the molecular mechanisms governing plasticity in this structure are poorly understood. Diverse studies have demonstrated a role for RSC in acquisition, early consolidation and retrieval similar to the hippocampus (HC), as well as in systems consolidation similar to the anterior cingulate cortex. Here, we asked whether established molecular and structural substrates of memory consolidation in the HC also engage in RSC shortly after learning...
March 1, 2018: Scientific Reports
Alexis C Carpenter, Daniel L Schacter
Episodic memory involves flexible retrieval processes that allow a person to link elements of distinct episodes in order to make novel inferences across events. In younger adults, we recently found that the same retrieval-related recombination mechanism that supports successful associative inference produces source misattributions as a consequence of erroneous binding of contextual elements from distinct episodes. In the current experiment, we found that older adults, in contrast to younger adults, did not show an increase in source misattributions following successful associative inference...
February 2018: Psychology and Aging
Patrick H Lim, Stephanie L Wert, Elif Tunc-Ozcan, Robert Marr, Adriana Ferreira, Eva E Redei
Aging and major depressive disorder are risk factors for dementia, including Alzheimer's Disease (AD), but the mechanism(s) linking depression and dementia are not known. Both AD and depression show greater prevalence in women. We began to investigate this connection using females of the genetic model of depression, the inbred Wistar Kyoto More Immobile (WMI) rat. These rats consistently display depression-like behavior compared to the genetically close control, the Wistar Kyoto Less Immobile (WLI) strain. Hippocampus-dependent contextual fear memory did not differ between young WLI and WMI females, but by middle-age female WMIs showed memory deficits compared to same age WLIs...
February 25, 2018: Behavioural Brain Research
Nathalie Alvarez-Ricartes, Patricia Oliveros-Matus, Cristhian Mendoza, Nelson Perez-Urrutia, Florencia Echeverria, Alexandre Iarkov, George E Barreto, Valentina Echeverria
Failure in fear extinction is one of the more troublesome characteristics of posttraumatic stress disorder (PTSD). Cotinine facilitates fear memory extinction and reduces depressive-like behavior when administered 24 h after fear conditioning in mice. In this study, it was investigated the behavioral and molecular effects of cotinine, and other antidepressant preparations infused intranasally. Intranasal (IN) cotinine, IN krill oil, IN cotinine plus krill oil, and oral sertraline were evaluated on depressive-like behavior and fear retention and extinction after fear conditioning in C57BL/6 mice...
February 27, 2018: Molecular Neurobiology
Matthieu Raveau, Denis Polygalov, Roman Boehringer, Kenji Amano, Kazuhiro Yamakawa, Thomas J McHugh
Down syndrome, the leading genetic cause of intellectual disability, results from an extra-copy of chromosome 21. Mice engineered to model this aneuploidy exhibit Down syndrome-like memory deficits in spatial and contextual tasks. While abnormal neuronal function has been identified in these models, most studies have relied on in vitro measures. Here, using in vivo recording in the Dp(16)1Yey model, we find alterations in the organization of spiking of hippocampal CA1 pyramidal neurons, including deficits in the generation of complex spikes...
February 27, 2018: ELife
A L Gilmore-Bykovskyi, N Rogus-Pulia
OBJECTIVES: Dysphagia, or impaired swallowing, is common in nursing home (NH) residents with dementia and contributes to malnutrition and diminished quality of life. Dysphagia also commonly leads to aspiration or passage of food or fluids into the airway, which can result in aspiration pneumonia-a leading cause of death for people with dementia. Currently available interventions for dysphagia aim to modify the risk of aspiration events primarily by modifying diet and positioning to improve the safety of an individual's swallow...
2018: Journal of Nutrition, Health & Aging
Rong-Ting Zhu, Xiang-Hui Liu, Yan-Wei Shi, Xiao-Guang Wang, Li Xue, Hu Zhao
Introduction: One hallmark symptom of post-traumatic stress disorder (PTSD) is an inability to restrict fear responses to the appropriate predictor. An infusion of glucocorticoids (GCs) after a high-intensity shock has been shown to induce PTSD-like memory impairments. In addition to GCs, noradrenergic signalling is also recognized as a key biomarker underlying PTSD symptomatology. Methods: To explore the role of the noradrenergic system in PTSD-like memory impairments, in this study, various doses of the β-adrenoceptor antagonist propranolol were systemically or bilaterally injected into the dorsal hippocampus immediately after unpaired cue-shock contextual fear conditioning, and then the rats were tested 24 h later...
February 2018: Brain and Behavior
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