Browsing by Subject "Memory Disorders"

Now showing 1 - 5 of 5
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    FASTKD2 and human memory: functional pathways and prospects for novel therapeutic target development for Alzheimer's disease and age-associated memory decline
    (Future Medicine, 2015) Ramanan, Vijay K.; Saykin, Andrew J.; Department of Radiology and Imaging Sciences, IU School of Medicine
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    Loss of function of NCOR1 and NCOR2 impairs memory through a novel GABAergic hypothalamus-CA3 projection
    (Springer Nature, 2019-02) Zhou, Wenjun; He, Yanlin; Rehman, Atteeq U.; Kong, Yan; Hong, Sungguan; Ding, Guolian; Yalamanchili, Hari Krishna; Wan, Ying-Wooi; Paul, Basil; Wang, Chuhan; Gong, Yingyun; Zhou, Wenxian; Liu, Hao; Dean, John; Scalais, Emmanuel; O’Driscoll, Mary; Morton, Jenny E.V.; Hou, Xinguo; Wu, Qi; Tong, Qingchun; Liu, Zhandong; Liu, Pengfei; Xu, Yong; Sun, Zheng; Biostatistics, IU School of Medicine
    Nuclear receptor corepressor 1 (NCOR1) and NCOR2 (also known as SMRT) regulate gene expression by activating histone deacetylase 3 through their deacetylase activation domain (DAD). We show that mice with DAD knock-in mutations have memory deficits, reduced anxiety levels, and reduced social interactions. Mice with NCOR1 and NORC2 depletion specifically in GABAergic neurons (NS-V mice) recapitulated the memory deficits and had reduced GABAA receptor subunit α2 (GABRA2) expression in lateral hypothalamus GABAergic (LHGABA) neurons. This was associated with LHGABA neuron hyperexcitability and impaired hippocampal long-term potentiation, through a monosynaptic LHGABA to CA3GABA projection. Optogenetic activation of this projection caused memory deficits, whereas targeted manipulation of LHGABA or CA3GABA neuron activity reversed memory deficits in NS-V mice. We describe de novo variants in NCOR1, NCOR2 or HDAC3 in patients with intellectual disability or neurodevelopmental disorders. These findings identify a hypothalamus-hippocampus projection that may link endocrine signals with synaptic plasticity through NCOR-mediated regulation of GABA signaling.
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    Memory Dysfunction.
    (Wolters Kluwer, 2015-06) Matthews, Brandy R.; Department of Neurology, IU School of Medicine
    Purpose of Review:: This article highlights the dissociable human memory systems of episodic, semantic, and procedural memory in the context of neurologic illnesses known to adversely affect specific neuroanatomic structures relevant to each memory system. Recent Findings:: Advances in functional neuroimaging and refinement of neuropsychological and bedside assessment tools continue to support a model of multiple memory systems that are distinct yet complementary and to support the potential for one system to be engaged as a compensatory strategy when a counterpart system fails. Summary:: Episodic memory, the ability to recall personal episodes, is the subtype of memory most often perceived as dysfunctional by patients and informants. Medial temporal lobe structures, especially the hippocampal formation and associated cortical and subcortical structures, are most often associated with episodic memory loss. Episodic memory dysfunction may present acutely, as in concussion; transiently, as in transient global amnesia (TGA); subacutely, as in thiamine deficiency; or chronically, as in Alzheimer disease. Semantic memory refers to acquired knowledge about the world. Anterior and inferior temporal lobe structures are most often associated with semantic memory loss. The semantic variant of primary progressive aphasia (svPPA) is the paradigmatic disorder resulting in predominant semantic memory dysfunction. Working memory, associated with frontal lobe function, is the active maintenance of information in the mind that can be potentially manipulated to complete goal-directed tasks. Procedural memory, the ability to learn skills that become automatic, involves the basal ganglia, cerebellum, and supplementary motor cortex. Parkinson disease and related disorders result in procedural memory deficits. Most memory concerns warrant bedside cognitive or neuropsychological evaluation and neuroimaging to assess for specific neuropathologies and guide treatment.
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    Memory impairment and alterations in prefrontal cortex gamma band activity following methamphetamine sensitization
    (Springer-Verlag, 2015-06) Janetsian, Sarine S.; Linsenbardt, David N.; Lapish, Christopher C.; Department of Psychology, School of Science
    RATIONALE: Repeated methamphetamine (MA) use leads to increases in the incentive motivational properties of the drug as well as cognitive impairments. These behavioral alterations persist for some time following abstinence, and neuroadaptations in the structure and function of the prefrontal cortex (PFC) are particularly important for their expression. However, there is a weak understanding of the changes in neural firing and oscillatory activity in the PFC evoked by repeated drug use, thus complicating the development of novel treatment strategies for addiction. OBJECTIVES: The purpose of the current study was to assess changes in cognitive and brain function following MA sensitization. METHODS: Sensitization was induced in rats, then temporal and recognition memory were assessed after 1 or 30 days of abstinence. Electrophysiological recordings from the medial PFC were also acquired from rats whereupon simultaneous measures of oscillatory and spiking activity were examined. RESULTS: Impaired temporal memory was observed after 1 and 30 days of abstinence. However, recognition memory was only impaired after 1 day of abstinence. An injection of MA profoundly decreased neuronal firing rate and the anesthesia-induced slow oscillation (SO) in both sensitized (SENS) and control (CTRL) rats. Strong correlations were observed between the SO and gamma band power, which was altered in SENS animals. A decrease in the number of neurons phase-locked to the gamma oscillation was also observed in SENS animals. CONCLUSIONS: The changes observed in PFC function may play an integral role in the expression of the altered behavioral phenotype evoked by MA sensitization.
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    Short-Term and Working Memory Impairments in Early-Implanted, Long-Term Cochlear Implant Users Are Independent of Audibility and Speech Production
    (Ovid Technologies (Wolters Kluwer) - Lippincott Williams & Wilkins, 2015-11) AuBuchon, Angela M.; Pisoni, David B.; Kronenberger, William G.; Department of Psychiatry, IU School of Medicine
    OBJECTIVE: To determine whether early-implanted, long-term cochlear implant (CI) users display delays in verbal short-term and working memory capacity when processes related to audibility and speech production are eliminated. DESIGN: Twenty-three long-term CI users and 23 normal-hearing controls each completed forward and backward digit span tasks under testing conditions that differed in presentation modality (auditory or visual) and response output (spoken recall or manual pointing). RESULTS: Normal-hearing controls reproduced more lists of digits than the CI users, even when the test items were presented visually and the responses were made manually via touchscreen response. CONCLUSIONS: Short-term and working memory delays observed in CI users are not due to greater demands from peripheral sensory processes such as audibility or from overt speech-motor planning and response output organization. Instead, CI users are less efficient at encoding and maintaining phonological representations in verbal short-term memory using phonological and linguistic strategies during memory tasks.