- StatPearls: Short Term Memory Impairment [BOOK]StatPearls Publishing: Treasure Island (FL)BOOK
- Short-term memory (STM), also referred to as short-term storage, or primary or active memory indicates different systems of memory involved in the retention of pieces of information (memory chunks) for a relatively short time (usually up to 30 seconds). In contrast, long-term memory (LTM) may hold an indefinite amount of information. The difference between the two memories, however, is not just i…
Short-term memory (STM), also referred to as short-term storage, or primary or active memory indicates different systems of memory involved in the retention of pieces of information (memory chunks) for a relatively short time (usually up to 30 seconds). In contrast, long-term memory (LTM) may hold an indefinite amount of information. The difference between the two memories, however, is not just in the 'time' variable but is above all functional. Nevertheless, the two systems are closely related. Practically, STM works as a kind of “scratchpad” for temporary recall of a limited number of data (in the verbal domain, roughly the George Miller’s ‘magical’ number 7 +/- 2 items) that come from the sensory register and are ready to be processed through attention and recognition. On the other side, information collected in the LTM storage consist of memories for the performance of actions or skills (i.e., procedural memories, “knowing how”) and memories of facts, rules, concepts, and events (i.e., declarative memories, “knowing that”). Declarative memory includes semantic and episodic memory. The former concerns broad knowledge of facts, rules, concepts, and propositions ('general knowledge'), the latter is related to personal and experienced events and the contexts in which they occurred ('personal recollection'). Although STM is closely related to the concept of ‘working memory’ (WM), STM and WM represent two distinct entities. STM, indeed, is a set of storage systems whereas WM indicates the cognitive operations and executive functions associated with the organization and manipulation of stored information. Nevertheless, one hears the terms STM and WM often used interchangeably. Furthermore, one must distinguish STM from the ‘sensory memory’ (SM) such as the acoustical echoic and iconic visual memories which are shorter in duration (fraction of a second) than STM and reflect the original sensation, or perception, of the stimulus. In other words, SM is specific to the stimulus' modality of presentation. This ‘raw’ sensory information undergoes processing, and when it becomes STM gets expressed in a format different from that perceived initially. The famous Atkinson and Shiffrin model (or multi-store model), proposed in the late 1960s, explains the functional correlations between STM, LTM, SM, and WM. Later on, a considerable number of studies demonstrated the anatomical and functional distinction between memory processes as well as neural correlates and functioning of STM and LTM subsystems. In light of these findings, several memory models have been postulated. While certain authors suggested the existence of a single memory system encompassing both short- and long-term storage, after 50 years the Atkinson and Shiffrin model remains a valid approach for an explanation of the memory dynamics. In light of more recent research, however, the model has several problems mostly concerning the characteristics of STM, the relationship between STM and WM as well as the transition from STM to LTM. Short-term memory: meaning and system(s) It is a storage system that includes several subsystems with limited capacity. Rather than being a limitation, this restriction is an evolutionary survival advantage, since it allows paying attention to limited but essential information, excluding confounding factors. It is the classic example of the prey that must focus on the hostile environment to recognize a possible attack by the predator. Given the functional peculiarities of the STM (collection of sensorial information), the subsystems are closely related to the modalities of sensory memory. As a consequence, there have been several sensorial-associated subsystems postulated, including the visuospatial, phonological (auditory-verbal), tactile, and olfactory domains. These subsystems involve different patterns and functional interconnections with the corresponding cortical and subcortical areas and centers. The concept of working memory In 1974, Baddeley and Hitch developed an alternative model of STM which they termed as working memory. Indeed, the WM model does not exclude the modal model but enriches its contents. On the other side, the short-term store can be used to characterize the functioning of the WM. WM refers more to the entire theoretical framework of the structures and processes used for the storage and temporary manipulation of information, of which STM is only a component. In other words, STM is a functional storage element, while WM is a set of processes that also involve storage phases. WM It is the memory that we constantly use, which is always "online" when we have to understand something or solve a problem or make an argument, the cognitive strategies for achieving short term goals. The proof of the importance of this sort of 'operating system' of memory shows by the evidence that WM deficits are associated with several developmental disorders of learning, including attention-deficit hyperactivity disorder (ADHD), dyslexia, and specific language impairment (SLI). Short-term and Long-term memory These types of memory can be classically distinguished based on storage capacity and duration. The capacity of the STM, indeed, has limitations in the amount and duration of information it can maintain. In contrast, LTM features a seemingly unlimited capacity that can last years. The functional distinctions between systems of memory storing and the exact mechanisms for how memories transfer from ST to LTM remain a controversial issue. Do STM and LTM represent one or more systems with specific subsystems? Although the STM probably represents a sub-structure of the LTM, which is a sort of long-term activated storage, rather than looking for a 'physical' division, it seems appropriate to verify the mechanisms of transition from a memory that is only a passage to a lasting memory. Although the classic multi-modal model proposed that storage of ST memories occurs automatically without manipulation, the matter seems to be more involved. The phenomenon concerns quantitative (number of memories) and qualitative (quality of memory) features. Regarding quantitative data, although the number of Miller of 7 +/- 2 items identifies the number of elements included among individual slots, the grouping of memory bits into larger chunks (chunking) could allow storing a lot more information of bigger size and continuing to keep the magic number. The qualitative issue, or memory modulation within processing, is a fascinating phenomenon. It seems that the elements of STM undergo processing, which provides a sort of editing that involves the fragmentation of each element (chunking) and its re-elaboration and re-elaboration. This phase of memory processing is called encoding and can condition subsequent processing, including storage, and retrieval. The encoding process encompasses automatic (without conscious awareness) and effortful processing (through attention, practice, and thought) and allows us to retrieve information to be used to make decisions, answer questions, and so on. There are three pathways followed during the encoding step: the visual (information represented as a picture), acoustic (information represented as a sound), and semantic encoding (the meaning of the information). The processes interconnect with each other, so that information is broken down into different components. During recovery, the pathway that has produced the coding facilitates the recovery of the other components through a singular chain reaction. A particular perfume, for instance, makes us recall a specific episode or image. Of note, the encoding process affects the recovery, but the recovery itself undergoes a series of potential changes that can alter the initial content. In neurofunctional terms, the difference between STM and LTM is the occurrence, in the LTM, of a series of events that must fix the engram(s) definitively. This effect occurs through the establishment of neural networks and expresses as neurofunctional phenomena including the long term potentiation (LTP) which is an increase in the strength of the neural transmission deriving from the strengthening of synaptic connections. This process requires gene expression and the synthesis of new proteins and is related to long-lasting structural alterations in the synapses (synaptic consolidation) of the brain areas involved such as the hippocampus is the case of declarative memories. The role of the hippocampal network Of note, the hippocampal neurogenesis regulates the maintenance of LTP. However, the hippocampal network, including the parahippocampal gyrus, hippocampus, and neocortical areas is not the place where memories are stored, but it has a crucial role in forming new memories and in their subsequent reactivation. It seems that the hippocampus has a limited capacity and acquires information quickly and automatically without keeping it for long. Over time, the originally available information becomes permanent in other brain structures (in the cortex), independently from the activity of the hippocampus itself. The crucial mechanism of this transfer is the reactivation ("replay") of the configurations of neural activity. In other words, the hippocampus and the medial temporal structures connected to it are crucial for holding an event as a whole as it distributes in an organized way memory traces. It is an operating system that through different software can store, organize, process, and recover hardware files. This hippocampal-guided reactivation (retrieval) leads to the creation of direct connections between the cortical traces and then to the formation of an integrated representation in the neocortex including the visual association cortex for visual memory, the temporal cortex for auditory memory, and the left lateral temporal cortex for knowledge of word meaning. Moreover, the hippocampus has other specific tasks, for example, in the spatial memory organization. Other brain areas are involved in memory processes; for example, the learning of motor skills has links to the activation of the cerebellar regions and brainstem nuclei. Furthermore, learning of perceptive activities (improvements in the processing of perceptive stimuli essential in everyday life activities such as understand spoken and written language) involves, basal ganglia and sensory and associative cortices whereas learning cognitive skills (related to problem-solving) involve the medial temporal lobes initially.
- Cigarette smoke exposure reduces leukemia inhibitory factor levels during respiratory syncytial viral infection. [Journal Article]Int J Chron Obstruct Pulmon Dis 2019; 14:1305-1315IJ
- CONCLUSIONS: Cigarette smoke is an important modulator for LIF expression in the lungs. Loss of LIF expression in COPD could contribute to a higher degree of lung injury during virus-associated exacerbations.
- Biomarkers for Alzheimer's Disease in Saliva: A Systematic Review. [Review]Dis Markers 2019; 2019:4761054DM
- CONCLUSIONS: Aβ42 and tau seem to be worthy candidates for future salivary biomarkers for AD, but other biomarkers such as lactoferrin and selected metabolites also have potential. More studies must be carried out with larger sample sizes and a standardization of the sampling and processing method. Factors such as diurnal variation, AD patients' decreased ability of oral self-care, and salivary flowrates must be taken into consideration.
- Cursive Eye-Writing With Smooth-Pursuit Eye-Movement Is Possible in Subjects With Amyotrophic Lateral Sclerosis. [Journal Article]Front Neurosci 2019; 13:538FN
- Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder causing a progressive motor weakness of all voluntary muscles, whose progression challenges communication modalities such as handwriting or speech. The current study investigated whether ALS subjects can use Eye-On-Line (EOL), a novel eye-operated communication device allowing, after training, to voluntarily control smooth-pursui…
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder causing a progressive motor weakness of all voluntary muscles, whose progression challenges communication modalities such as handwriting or speech. The current study investigated whether ALS subjects can use Eye-On-Line (EOL), a novel eye-operated communication device allowing, after training, to voluntarily control smooth-pursuit eye-movements (SPEM) so as to eye-write in cursive. To that aim, ALS participants (n = 12) with preserved eye-movements but impaired handwriting were trained during six on-site visits. The primary outcome of the study was the recognition of eye-written digits (0-9) from ALS and healthy control subjects by naïve "readers." Changes in oculomotor performance and the safety of EOL were also evaluated. At the end of the program, 69.4% of the eye-written digits from 11 ALS subjects were recognized by naïve readers, similar to the 67.3% found for eye-written digits from controls participants, with however, large inter-individual differences in both groups of "writers." Training with EOL was associated with a transient fatigue leading one ALS subject to drop out the study at the fifth visit. Otherwise, itching eyes was the most common adverse event (3 subjects). This study shows that, despite the impact of ALS on the motor system, most ALS participants could improve their mastering of eye-movements, so as to produce recognizable eye-written digits, although the eye-traces sometimes needed smoothing to ease digit legibility from both ALS subjects and control participants. The capability to endogenously and voluntarily generate eye-traces using EOL brings a novel way to communicate for disabled individuals, allowing creative personal and emotional expression.
- Proteostasis and ALS: protocol for a phase II, randomised, double-blind, placebo-controlled, multicentre clinical trial for colchicine in ALS (Co-ALS). [Journal Article]BMJ Open 2019; 9(5):e028486BO
- Disruptions of proteasome and autophagy systems are central events in amyotrophic lateral sclerosis (ALS) and support the urgent need to find therapeutic compounds targeting these processes. The heat shock protein B8 (HSPB8) recognises and promotes the autophagy-mediated removal of misfolded mutant SOD1 and TDP-43 fragments from ALS motor neurons (MNs), as well as aggregating species of dipeptide…
Disruptions of proteasome and autophagy systems are central events in amyotrophic lateral sclerosis (ALS) and support the urgent need to find therapeutic compounds targeting these processes. The heat shock protein B8 (HSPB8) recognises and promotes the autophagy-mediated removal of misfolded mutant SOD1 and TDP-43 fragments from ALS motor neurons (MNs), as well as aggregating species of dipeptides produced in C9ORF72-related diseases. In ALS-SOD1 mice and in human ALS autopsy specimens, HSPB8 is highly expressed in spinal cord MNs that survive at the end stage of disease. Moreover, the HSPB8-BAG3-HSP70 complex maintains granulostasis, which avoids conversion of dynamic stress granules (SGs) into aggregation-prone assemblies. We will perform a randomised clinical trial (RCT) with colchicine, which enhances the expression of HSPB8 and of several autophagy players, blocking TDP-43 accumulation and exerting crucial activities for MNs function.
- A case of advanced pancreatic neuroendocrine tumor in which octreotide long-acting repeatable was effective after failure of everolimus and sunitinib. [Case Reports]Int Cancer Conf J 2019; 8(1):24-28IC
- Molecular targeted drugs, such as everolimus and sunitinib, have shown efficacy against advanced pancreatic neuroendocrine tumors. Octreotide, a somatostatin analogue, improves the hormone-related symptoms in patients with neuroendocrine tumors. Furthermore, it has been reported that octreotide has antitumor activity in patients with metastatic midgut neuroendocrine tumors. However, whether octre…
Molecular targeted drugs, such as everolimus and sunitinib, have shown efficacy against advanced pancreatic neuroendocrine tumors. Octreotide, a somatostatin analogue, improves the hormone-related symptoms in patients with neuroendocrine tumors. Furthermore, it has been reported that octreotide has antitumor activity in patients with metastatic midgut neuroendocrine tumors. However, whether octreotide has anti-proliferative effects in patients with advanced pancreatic neuroendocrine tumors is not fully understood. We report a 71-year-old man with multiple liver metastases of pancreatic neuroendocrine tumor. He was treated with everolimus 10 mg daily and sunitinib 25 mg daily on days 1-14 every 3 weeks at the physician's discretion. However, these molecular targeted drugs were discontinued due to disease progression or severe adverse effects. Octreotide long-acting repeatable was administered continuously from the initiation of everolimus treatment. The tumor marker level markedly decreased and the metastatic liver lesions showed shrinkage with octreotide treatment. Immunohistochemistry of tumor specimens obtained before treatment showed that somatostatin receptor 2, a high-affinity receptor for octreotide, was highly expressed. The clinical course of this patient suggested that octreotide long-acting repeatable may be a treatment option for advanced pancreatic neuroendocrine tumors after failure of everolimus and sunitinib. Further clinical trials are warranted to determine whether the expression of somatostatin receptor 2 in tumor tissues is predictive of octreotide efficacy.
- Clinical Importance of Estrogen Receptor 1 (ESR1) Gene Polymorphisms and Their Expression Patterns in Coronary Artery Disease Patients: A Study from India. [Journal Article]Indian J Clin Biochem 2019; 34(2):133-142IJ
- The influence of Estrogen Receptor 1 (ESR1) gene -397T>C (PvuII) and -351A>G (XbaI) polymorphisms on the risk of development of coronary artery disease (CAD) in the north Indian population was analysed. We hypothesized that ESR1 gene polymorphisms may influence the susceptibility to CAD through variation in Estrogen Receptor α (ERα) expression. To assess this concept, we evaluated ERα mRNA expres…
The influence of Estrogen Receptor 1 (ESR1) gene -397T>C (PvuII) and -351A>G (XbaI) polymorphisms on the risk of development of coronary artery disease (CAD) in the north Indian population was analysed. We hypothesized that ESR1 gene polymorphisms may influence the susceptibility to CAD through variation in Estrogen Receptor α (ERα) expression. To assess this concept, we evaluated ERα mRNA expression in blood plasma of CAD patients. The study included hundred CAD patients who showed presence of greater than 50% luminal stenosis in at least one major coronary artery in angiography along with hundred age and sex matched healthy controls. The ESR1 polymorphisms were investigated by PCR-RFLP. Quantitative Real Time PCR was carried out for the measurement of ERα mRNA expression. The results showed that genotypic frequencies of ESR1 -397T>C and -351A>G gene polymorphisms were significantly higher in CAD patients than control subjects (p < 0.0001). A significantly increased CAD risk was also found in dominant and codominant inheritance model for both of the SNPs. In gender based analysis these findings were replicated only in male subgroup. In case of -397T>C polymorphism, the ERα mRNA expression was highest in CAD patients with wild type homozygous TT genotype (2-∆ct = 0.28). A mutant 'C' allele, dose dependent, significant decrease in trend in ERα mRNA expression was observed, with lowest expression in mutant homozygous CC genotype (2-∆ct = 0.09), and intermediate expression level in heterozygous TC genotype (2-∆ct = 0.14) subgroups of CAD patients. In conclusion, this study demonstrates a significantly heightened risk of CAD associated with the inheritance of mutant genotypes of ESR1 -397T>C and -351A>G gene polymorphisms, in the north Indian population. This is the first report of a lowered ERα mRNA expression in conjunction with the presence of mutant 'C' allele of ESR1 -397T>C polymorphism with consequent increased CAD susceptibility.
- Understanding, educating, and supporting children with specific learning disabilities: 50 years of science and practice. [Journal Article]Am Psychol 2019AP
- Specific learning disabilities (SLDs) are highly relevant to the science and practice of psychology, both historically and currently, exemplifying the integration of interdisciplinary approaches to human conditions. They can be manifested as primary conditions-as difficulties in acquiring specific academic skills-or as secondary conditions, comorbid to other developmental disorders such as attent…
Specific learning disabilities (SLDs) are highly relevant to the science and practice of psychology, both historically and currently, exemplifying the integration of interdisciplinary approaches to human conditions. They can be manifested as primary conditions-as difficulties in acquiring specific academic skills-or as secondary conditions, comorbid to other developmental disorders such as attention-deficit hyperactivity disorder. In this synthesis of historical and contemporary trends in research and practice, we mark the 50th anniversary of the recognition of SLDs as a disability in the United States. Specifically, we address the manifestations, occurrence, identification, comorbidity, etiology, and treatment of SLDs, emphasizing the integration of information from the interdisciplinary fields of psychology, education, psychiatry, genetics, and cognitive neuroscience. SLDs, exemplified here by specific word reading, reading comprehension, mathematics, and written expression disabilities, represent spectrum disorders, each occurring in approximately 5% to 15% of the school-aged population. In addition to risk for academic deficiencies and related functional social, emotional, and behavioral difficulties, those with SLDs often have poorer long-term social and vocational outcomes. Given the high rate of occurrence of SLDs and their lifelong negative impact on functioning if not treated, it is important to establish and maintain effective prevention, surveillance, and treatment systems involving professionals from various disciplines trained to minimize the risk and maximize the protective factors for SLDs. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
- Genetic associations between genes in the renin-angiotensin-aldosterone system and renal disease: a systematic review and meta-analysis. [Journal Article]BMJ Open 2019; 9(4):e026777BO
- CONCLUSIONS: Further biological pathway and functional analyses of the RAAS gene polymorphisms will help define how variation in components of the RAAS pathway contributes to CKD.
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- Therapist-Guided Tablet-Based Telerehabilitation for Patients With Aphasia: Proof-of-Concept and Usability Study. [Journal Article]JMIR Rehabil Assist Technol 2019; 6(1):e13163JR
- CONCLUSIONS: Based on the questionnaire scores, the system is well accepted and simple to use for patients and therapists. Furthermore, the new tablet computer-based app and the hierarchical language exercise structure allow patients with different types of aphasia to train with different doses and intensities independently at home. Thus, the novel system has potential for treatment of patients with aphasia as a supplement to face-to-face therapy.