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  1. Should brain chip implants for memory and cognitive enhancement be banned in competitive national examinations?
    Chin AHB, Alsomali N, Muhsin SM
    Neurosurg Rev, 2024 May 25;47(1):234.
    PMID: 38795179 DOI: 10.1007/s10143-024-02471-4
    In a recent medical breakthrough, Elon Musk's startup company Neuralink implanted the first brain chip in a human patient, purportedly for aiding paralysis. While certainly representing a significant medical milestone for many patients afflicted with debilitating brain and spinal cord injuries, as well as devastating neurodegenerative diseases such as Parkinson's and Alzheimer's, it must be noted that this very same technology can also be manipulated for human memory or cognitive enhancement. What happens if a brain chip were to be developed that can significantly improve either IQ (intelligence quotient) or memory, and these were then implanted in people to enhance their performance in highly competitive national examinations for college entrance or gaining employment in civil service positions? This article therefore discusses the ethical implications of this nascent technology platform, and whether its use in competitive national examinations should be banned.
    Matched MeSH terms: Memory/physiology
  2. Human memory retention and recall processes. A review of EEG and fMRI studies
    Amin H, Malik AS
    Neurosciences (Riyadh), 2013 Oct;18(4):330-44.
    PMID: 24141456
    Human memory is an important concept in cognitive psychology and neuroscience. Our brain is actively engaged in functions of learning and memorization. Generally, human memory has been classified into 2 groups: short-term/working memory, and long-term memory. Using different memory paradigms and brain mapping techniques, psychologists and neuroscientists have identified 3 memory processes: encoding, retention, and recall. These processes have been studied using EEG and functional MRI (fMRI) in cognitive and neuroscience research. This study reviews previous research reported for human memory processes, particularly brain behavior in memory retention and recall processes with the use of EEG and fMRI. We discuss issues and challenges related to memory research with EEG and fMRI techniques.
    Matched MeSH terms: Memory/physiology*
  3. What proteins are involved in learning and memory?
    Perumal R, Tan I
    IUBMB Life, 2007 Jul;59(7):465-8.
    PMID: 17654123
    Matched MeSH terms: Memory/physiology*
  4. Fulltext P300 correlates with learning & memory abilities and fluid intelligence
    Amin HU, Malik AS, Kamel N, Chooi WT, Hussain M
    J Neuroeng Rehabil, 2015;12:87.
    PMID: 26400233 DOI: 10.1186/s12984-015-0077-6
    Educational psychology research has linked fluid intelligence with learning and memory abilities and neuroimaging studies have specifically associated fluid intelligence with event related potentials (ERPs). The objective of this study is to find the relationship of ERPs with learning and memory recall and predict the memory recall score using P300 (P3) component.
    Matched MeSH terms: Memory/physiology*
  5. New insights on brain-derived neurotrophic factor epigenetics: from depression to memory extinction
    Poon CH, Heng BC, Lim LW
    Ann N Y Acad Sci, 2021 01;1484(1):9-31.
    PMID: 32808327 DOI: 10.1111/nyas.14458
    Advances in characterizing molecular profiles provide valuable insights and opportunities for deciphering the neuropathology of depression. Although abnormal brain-derived neurotrophic factor (BDNF) expression in depression has gained much support from preclinical and clinical research, how it mediates behavioral alterations in the depressed state remains largely obscure. Environmental factors contribute significantly to the onset of depression and produce robust epigenetic changes. Epigenetic regulation of BDNF, as one of the most characterized gene loci in epigenetics, has recently emerged as a target in research on memory and psychiatric disorders. Specifically, epigenetic alterations of BDNF exons are heavily involved in mediating memory functions and antidepressant effects. In this review, we discuss key research on stress-induced depression from both preclinical and clinical studies, which revealed that differential epigenetic regulation of specific BDNF exons is associated with depression pathophysiology. Considering that BDNF has a central role in depression, we argue that memory extinction, an adaptive response to fear exposure, is dependent on BDNF modulation and holds promise as a prospective target for alleviating or treating depression and anxiety disorders.
    Matched MeSH terms: Memory/physiology
  6. Memory and time: Backward and forward telescoping in Alzheimer's disease
    El Haj M, Janssen SMJ, Antoine P
    Brain Cogn, 2017 10;117:65-72.
    PMID: 28629646 DOI: 10.1016/j.bandc.2017.06.005
    Backward and forward telescoping are opposite timing biases. The former refers to misattributing events to earlier dates, whereas the latter refers to misattributing events to later dates. The present study investigated both biases in participants with Alzheimer's Disease (AD) and healthy older adults, matched on age, sex, and education level. Participants were asked to recall the years when five remote and five recent public events had occurred. They were also assessed with a cognitive and clinical battery that included a context memory task on which they had to associate letters and locations. Results showed backward telescoping for recent events and forward telescoping for remote events in AD participants and older adults. Furthermore, poorer context recall was observed in AD participants and older adults displaying backward telescoping than in those displaying forward telescoping. These findings suggest an association between the amount of contextual information recalled and the direction of the timing bias. Backward telescoping can be associated with deficiencies in retrieving context characteristics of events, which have been associated with retrograde amnesia and pathological changes to the hippocampus in AD.
    Matched MeSH terms: Memory/physiology*
  7. TRPM4 inhibition improves spatial memory impairment and hippocampal long-term potentiation deficit in chronic cerebral hypoperfused rats
    Hazalin NAMN, Liao P, Hassan Z
    Behav Brain Res, 2020 09 01;393:112781.
    PMID: 32619565 DOI: 10.1016/j.bbr.2020.112781
    Chronic cerebral hypoperfusion (CCH) been well characterized as a common pathological status contributing to neurodegenerative diseases such as Alzheimer's disease and vascular dementia. CCH is an important factor that leads to cognitive impairment, but the underlying neurobiological mechanism is poorly understood and no effective treatment is available. Recently, transient receptor potential melastatin 4 (TRPM4) cation channel has been identified as an important molecular element in focal cerebral ischemia. Over activation of the channel is a major molecular mechanism of oncotic cell death. However, the role of TRPM4 in CCH that propagates global brain hypoxia have not been explored. Therefore, the present study is designed to investigate the effect of TRPM4 inhibition on the cognitive functions of the rats following CCH via permanent bilateral occlusion of common carotid arteries (PBOCCA) model. In this model, treatment with siRNA suppressed TRPM4 expression at both the mRNA and protein levels and improved cognitive deficits of the CCH rats without affecting their motor function. Furthermore, treatment with siRNA rescued the LTP impairment in CCH-induced rats. Consistent with the restored of LTP, western blot analysis revealed that siRNA treatment prevented the reduction of synaptic proteins, including calcium/calmodulin-dependent kinase II alpha (CaMKIIα) and brain-derived neurotrophic factor (BDNF) in brain regions of CCH rats. The present findings provide a novel role of TRPM4 in restricting cognitive functions in CCH and suggest inhibiting TRPM4 may represent a promising therapeutic strategy in targeting ion channels to prevent the progression of cognitive deficits induced by ischemia.
    Matched MeSH terms: Spatial Memory/physiology*
  8. Effects of modality and repetition in a continuous recognition memory task: Repetition has no effect on auditory recognition memory
    Amir Kassim A, Rehman R, Price JM
    Acta Psychol (Amst), 2018 Apr;185:72-80.
    PMID: 29407247 DOI: 10.1016/j.actpsy.2018.01.012
    Previous research has shown that auditory recognition memory is poorer compared to visual and cross-modal (visual and auditory) recognition memory. The effect of repetition on memory has been robust in showing improved performance. It is not clear, however, how auditory recognition memory compares to visual and cross-modal recognition memory following repetition. Participants performed a recognition memory task, making old/new discriminations to new stimuli, stimuli repeated for the first time after 4-7 intervening items (R1), or repeated for the second time after 36-39 intervening items (R2). Depending on the condition, participants were either exposed to visual stimuli (2D line drawings), auditory stimuli (spoken words), or cross-modal stimuli (pairs of images and associated spoken words). Results showed that unlike participants in the visual and cross-modal conditions, participants in the auditory recognition did not show improvements in performance on R2 trials compared to R1 trials. These findings have implications for pedagogical techniques in education, as well as for interventions and exercises aimed at boosting memory performance.
    Matched MeSH terms: Memory/physiology
  9. Spatial memory performance of Wistar rats exposed to mobile phone
    Narayanan SN, Kumar RS, Potu BK, Nayak S, Mailankot M
    Clinics (Sao Paulo), 2009;64(3):231-4.
    PMID: 19330250
    INTRODUCTION: With the tremendous increase in number of mobile phone users world wide, the possible risks of this technology have become a serious concern.

    OBJECTIVE: We tested the effects of mobile phone exposure on spatial memory performance.

    MATERIALS AND METHODS: Male Wistar rats (10-12 weeks old) were exposed to 50 missed calls/day for 4 weeks from a GSM (900/1800 MHz) mobile phone in vibratory mode (no ring tone). After the experimental period, the animals were tested for spatial memory performance using the Morris water maze test.

    RESULTS: Both phone exposed and control animals showed a significant decrease in escape time with training. Phone exposed animals had significantly (approximately 3 times) higher mean latency to reach the target quadrant and spent significantly (approximately 2 times) less time in the target quadrant than age- and sex-matched controls.

    CONCLUSION: Mobile phone exposure affected the acquisition of learned responses in Wistar rats. This in turn points to the poor spatial navigation and the object place configurations of the phone-exposed animals.

    Matched MeSH terms: Memory/physiology
  10. Fulltext The effects of age on the strategic use of pitch accents in memory for discourse: a processing-resource account
    Fraundorf SH, Watson DG, Benjamin AS
    Psychol Aging, 2012 Mar;27(1):88-98.
    PMID: 21639646 DOI: 10.1037/a0024138
    In two experiments, we investigated age-related changes in how prosodic pitch accents affect memory. Participants listened to recorded discourses that contained two contrasts between pairs of items (e.g., one story contrasted British scientists with French scientists and Malaysia with Indonesia). The end of each discourse referred to one item from each pair; these references received a pitch accent that either denoted contrast (L + H* in the ToBI system) or did not (H*). A contrastive accent on a particular pair improved later recognition memory equally for young and older adults. However, older adults showed decreased memory if the other pair received a contrastive accent (Experiment 1). Young adults with low working memory performance also showed this penalty (Experiment 2). These results suggest that pitch accents guide processing resources to important information for both older and younger adults but diminish memory for less important information in groups with reduced resources, including older adults.
    Matched MeSH terms: Memory/physiology*
  11. Fulltext Motor dexterity and strength depend upon integrity of the attention-control system
    Rinne P, Hassan M, Fernandes C, Han E, Hennessy E, Waldman A, et al.
    Proc Natl Acad Sci U S A, 2018 01 16;115(3):E536-E545.
    PMID: 29284747 DOI: 10.1073/pnas.1715617115
    Attention control (or executive control) is a higher cognitive function involved in response selection and inhibition, through close interactions with the motor system. Here, we tested whether influences of attention control are also seen on lower level motor functions of dexterity and strength-by examining relationships between attention control and motor performance in healthy-aged and hemiparetic-stroke subjects (n = 93 and 167, respectively). Subjects undertook simple-tracking, precision-hold, and maximum force-generation tasks, with each hand. Performance across all tasks correlated strongly with attention control (measured as distractor resistance), independently of factors such as baseline performance, hand use, lesion size, mood, fatigue, or whether distraction was tested during motor or nonmotor cognitive tasks. Critically, asymmetric dissociations occurred in all tasks, in that severe motor impairment coexisted with normal (or impaired) attention control whereas normal motor performance was never associated with impaired attention control (below a task-dependent threshold). This implies that dexterity and force generation require intact attention control. Subsequently, we examined how motor and attention-control performance mapped to lesion location and cerebral functional connectivity. One component of motor performance (common to both arms), as well as attention control, correlated with the anatomical and functional integrity of a cingulo-opercular "salience" network. Independently of this, motor performance difference between arms correlated negatively with the integrity of the primary sensorimotor network and corticospinal tract. These results suggest that the salience network, and its attention-control function, are necessary for virtually all volitional motor acts while its damage contributes significantly to the cardinal motor deficits of stroke.
    Matched MeSH terms: Memory/physiology
  12. Fulltext Mood and memory function in ovariectomised rats exposed to social instability stress
    Al-Rahbi B, Zakaria R, Othman Z, Hassan A, Muthuraju S, Wan Mohammad WM
    Biomed Res Int, 2013;2013:493643.
    PMID: 23841073 DOI: 10.1155/2013/493643
    This study aims to compare the effects of social instability stress on memory and anxiety- and depressive-like behaviour between sham-operated controls and ovariectomised (OVX) rats. Forty adult female Sprague-Dawley rats (8 weeks old) were randomly divided into four groups, (n = 10 per group). These were non-stressed sham-operated control rats, stressed sham-operated control rats, non-stressed OVX rats, and stressed OVX rats. The rats were subjected to social instability stress procedure for 15 days. Novel object recognition, open field, and forced swim tests were conducted after the stress procedure. Serum estradiol, ACTH and corticosterone levels were measured using commercially available ELISA kits. Lower serum estradiol level and uterine weight with higher weight gain were observed in OVX rats compared to sham-operated controls. Serum ACTH, and corticosterone levels were higher in stressed compared to non-stressed groups. Memory deficit and anxiety- and depressive-like behaviour were significantly increased in stressed compared to non-stressed OVX rats but these changes were not seen in sham-operated controls. These results suggest that the high circulating corticosterone acts synergistically with low circulating estradiol to exert negative effects on mood and memory function.
    Matched MeSH terms: Memory/physiology
  13. Association of oxidative stress and memory performance in postmenopausal women receiving estrogen-progestin therapy
    Shafin N, Zakaria R, Hussain NH, Othman Z
    Menopause, 2013 Jun;20(6):661-6.
    PMID: 23715378 DOI: 10.1097/GME.0b013e31827758c6
    The aim of this study was to examine the association between changes in blood oxidative stress level/activity and changes in memory performance among postmenopausal women.
    Matched MeSH terms: Memory/physiology*
  14. Fulltext Nicotine-prevented learning and memory impairment in REM sleep-deprived rat is modulated by DREAM protein in the hippocampus
    Abd Rashid N, Hapidin H, Abdullah H, Ismail Z, Long I
    Brain Behav, 2017 06;7(6):e00704.
    PMID: 28638710 DOI: 10.1002/brb3.704
    INTRODUCTION: REM sleep deprivation is associated with impairment in learning and memory, and nicotine treatment has been shown to attenuate this effect. Recent studies have demonstrated the importance of DREAM protein in learning and memory processes. This study investigates the association of DREAM protein in REM sleep-deprived rats hippocampus upon nicotine treatment.

    METHODS: Male Sprague Dawley rats were subjected to normal condition, REM sleep deprivation and control wide platform condition for 72 hr. During this procedure, saline or nicotine (1 mg/kg) was given subcutaneously twice a day. Then, Morris water maze (MWM) test was used to assess learning and memory performance of the rats. The rats were sacrificed and the brain was harvested for immunohistochemistry and Western blot analysis.

    RESULTS: MWM test found that REM sleep deprivation significantly impaired learning and memory performance without defect in locomotor function associated with a significant increase in hippocampus DREAM protein expression in CA1, CA2, CA3, and DG regions and the mean relative level of DREAM protein compared to other experimental groups. Treatment with acute nicotine significantly prevented these effects and decreased expression of DREAM protein in all the hippocampus regions but only slightly reduce the mean relative level of DREAM protein.

    CONCLUSION: This study suggests that changes in DREAM protein expression in CA1, CA2, CA3, and DG regions of rat's hippocampus and mean relative level of DREAM protein may involve in the mechanism of nicotine treatment-prevented REM sleep deprivation-induced learning and memory impairment in rats.

    Matched MeSH terms: Memory/physiology
  15. Fulltext Differential expression of entorhinal cortex and hippocampal subfields α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors enhanced learning and memory of rats following administration of Centella asiatica
    Wong JH, Muthuraju S, Reza F, Senik MH, Zhang J, Mohd Yusuf Yeo NAB, et al.
    Biomed Pharmacother, 2019 Feb;110:168-180.
    PMID: 30469081 DOI: 10.1016/j.biopha.2018.11.044
    Centella asiatica (CA) is a widely used traditional herb, notably for its cognitive enhancing effect and potential to increase synaptogenesis. The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and N-methyl-D-aspartate receptors (NMDARs) mediate fast excitatory neurotransmission with key roles in long-term potentiation which is believed to be the cellular mechanism of learning and memory. Improved learning and memory can be an indication to the surface expression level of these receptors. Our previous study demonstrated that administration of CA extract improved learning and memory and enhanced expression of AMPAR GluA1 subunit while exerting no significant effects on GABAA receptors of the hippocampus in rats. Hence, to further elucidate the effects of CA, this study investigated the effects of CA extract in recognition memory and spatial memory, and its effects on AMPAR GluA1 and GluA2 subunit and NMDAR GluN2 A and GluN2B subunit expression in the entorhinal cortex (EC) and hippocampal subfields CA1 and CA3. The animals were administered with saline, 100 mg/kg, 300 mg/kg, and 600 mg/kg of CA extract through oral gavage for 14 days, followed by behavioural analysis through Open Field Test (OFT), Novel Object Recognition Task (NORT), and Morris Water Maze (MWM) and lastly morphological and immunohistochemical analysis of the surface expression of AMPAR and NMDAR subunits were performed. The results showed that 14 days of administration of 600 mg/kg of CA extract significantly improved memory assessed through NORT while 300 mg/kg of CA extract significantly improved memory of the animals assessed through MWM. Immunohistochemical analysis revealed differential modulation effects on the expressions of receptor subunits across CA1, CA3 and EC. The CA extract at the highest dose (600 mg/kg) significantly enhanced the expression of AMPAR subunit GluA1 and GluA2 in CA1, CA3 and EC, and NMDAR subunit GluN2B in CA1 and CA3 compared to control. At 300 mg/kg, CA significantly increased expression of AMPAR GluA1 in CA1 and EC, and GluA2 in CA1, CA3 and EC while 100 mg/kg of CA significantly increased expression of only AMPAR subunit GluA2 in CA3 and EC. Expression of NMDAR subunit GluN2 A was significantly reduced in the CA3 (at 100, 300, and 600 mg/kg) while no significant changes of subunit expression was observed in CA1 and EC compared to control. The results suggest that the enhanced learning and memory observed in animals administered with CA was mainly mediated through increased expression of AMPAR GluA1 and GluA2 subunits and differential expression of NMDAR GluN2 A and GluN2B subunits in the hippocampal subfields and EC. With these findings, the study revealed a new aspect of cognitive enhancing effect of CA and its therapeutic potentials through modulating receptor subunit expression.
    Matched MeSH terms: Spatial Memory/physiology
  16. Behavioral effects of deep brain stimulation of different areas of the Papez circuit on memory- and anxiety-related functions
    Hescham S, Jahanshahi A, Meriaux C, Lim LW, Blokland A, Temel Y
    Behav Brain Res, 2015 Oct 1;292:353-60.
    PMID: 26119240 DOI: 10.1016/j.bbr.2015.06.032
    Deep brain stimulation (DBS) has gained interest as a potential therapy for advanced treatment-resistant dementia. However, possible targets for DBS and the optimal stimulation parameters are not yet clear. Here, we compared the effects of DBS of the CA1 sub-region of the hippocampus, mammillothalamic tract, anterior thalamic nucleus, and entorhinal cortex in an experimental rat model of dementia. Rats with scopolamine-induced amnesia were assessed in the object location task with different DBS parameters. Moreover, anxiety-related side effects were evaluated in the elevated zero maze and open field. After sacrifice, we applied c-Fos immunohistochemistry to assess which memory-related regions were affected by DBS. When comparing all structures, DBS of the entorhinal cortex and CA1 sub-region was able to restore memory loss when a specific set of stimulation parameters was used. No anxiety-related side effects were found following DBS. The beneficial behavioral performance of CA1 DBS rats was accompanied with an activation of cells in the anterior cingulate gyrus. Therefore, we conclude that acute CA1 DBS restores memory loss possibly through improved attentional and cognitive processes in the limbic cortex.
    Matched MeSH terms: Memory/physiology*
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