scholarly journals A Diverse Range of Factors Affect the Nature of Neural Representations Underlying Short-Term Memory

2018 ◽  
Author(s):  
A. Emin Orhan ◽  
Wei Ji Ma
Keyword(s):  
Neural Circuits ◽  
Short Term Memory ◽  
Persistent Activity ◽  
Short Term ◽  
Diverse Range ◽  
Term Memory ◽  
Temporal Complexity ◽  
Wide Range ◽  
Activity Models ◽  
The Brain

AbstractSequential and persistent activity models are two prominent models of short-term memory in neural circuits. In persistent activity models, memories are represented in persistent or nearly persistent activity patterns across a population of neurons, whereas in sequential models, memories are represented dynamically by a sequential pattern of activity across the population. Experimental evidence for both types of model in the brain has been reported previously. However, it has been unclear under what conditions these two qualitatively different types of solutions emerge in neural circuits. Here, we address this question by training recurrent neural networks on several short-term memory tasks under a wide range of circuit and task manipulations. We show that sequential and nearly persistent solutions are both part of a spectrum that emerges naturally in trained networks under different conditions. Fixed delay durations, tasks with higher temporal complexity, strong network coupling, motion-related dynamic inputs and prior training in a different task favor more sequential solutions, whereas variable delay durations, tasks with low temporal complexity, weak network coupling and symmetric Hebbian short-term synaptic plasticity favor more persistent solutions. Our results help clarify some seemingly contradictory experimental results on the existence of sequential vs. persistent activity based memory mechanisms in the brain.

scholarly journals Persistent activity in a recurrent circuit underlies courtship memory in Drosophila

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Xiaoliang Zhao ◽  
Daniela Lenek ◽  
Ugur Dag ◽  
Barry J Dickson ◽  
Krystyna Keleman
Keyword(s):  
Dopaminergic Neurons ◽  
Mushroom Body ◽  
Neural Circuits ◽  
Short Term Memory ◽  
Persistent Activity ◽  
Short Term ◽  
Present Evidence ◽  
Term Memory ◽  
Time Periods ◽  
Over Time

Recurrent connections are thought to be a common feature of the neural circuits that encode memories, but how memories are laid down in such circuits is not fully understood. Here we present evidence that courtship memory in Drosophila relies on the recurrent circuit between mushroom body gamma (MBγ), M6 output, and aSP13 dopaminergic neurons. We demonstrate persistent neuronal activity of aSP13 neurons and show that it transiently potentiates synaptic transmission from MBγ>M6 neurons. M6 neurons in turn provide input to aSP13 neurons, prolonging potentiation of MBγ>M6 synapses over time periods that match short-term memory. These data support a model in which persistent aSP13 activity within a recurrent circuit lays the foundation for a short-term memory.

scholarly journals Fundamental bound on the persistence and capacity of short-term memory stored as graded persistent activity

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Onur Ozan Koyluoglu ◽  
Yoni Pertzov ◽  
Sanjay Manohar ◽  
Masud Husain ◽  
Ila R Fiete
Keyword(s):  
Human Performance ◽  
Short Term Memory ◽  
Memory Performance ◽  
Persistent Activity ◽  
Short Term ◽  
Noisy Channels ◽  
Storage Duration ◽  
Term Memory ◽  
Activity Networks ◽  
The Brain

It is widely believed that persistent neural activity underlies short-term memory. Yet, as we show, the degradation of information stored directly in such networks behaves differently from human short-term memory performance. We build a more general framework where memory is viewed as a problem of passing information through noisy channels whose degradation characteristics resemble those of persistent activity networks. If the brain first encoded the information appropriately before passing the information into such networks, the information can be stored substantially more faithfully. Within this framework, we derive a fundamental lower-bound on recall precision, which declines with storage duration and number of stored items. We show that human performance, though inconsistent with models involving direct (uncoded) storage in persistent activity networks, can be well-fit by the theoretical bound. This finding is consistent with the view that if the brain stores information in patterns of persistent activity, it might use codes that minimize the effects of noise, motivating the search for such codes in the brain.

An Integrated Molar/Molecular Model of the Brain

1972 ◽  
Vol 30 (2) ◽  
pp. 343-368 ◽  
Author(s):  
Alan Einar Hendrickson
Keyword(s):  
Action Potentials ◽  
Short Term Memory ◽  
Molecular Model ◽  
Spike Trains ◽  
Mass Action ◽  
Small Species ◽  
Short Term ◽  
Term Memory ◽  
Anaesthetic Agents ◽  
The Brain

A model of the brain is presented at both molecular and molar levels. Communication between neurons is thought to be a kind of telegraph code, with the information being coded as the permutation of four possible interval values between successive action potentials in spike trains. A small species of RNA molecule is thought to be the memory molecule, and the four possible nucleotide bases of RNA correspond to the four possible interval values. The model is shown to account for generalization, speed of retrieval, mass action, long- and short-term memory, forgetting, operant and classical conditioning, intelligence, reaction time, the action of anaesthetic agents, and some aspects of personality. Some evidence from multidisciplinary sources is presented in support of the major features of the model.

A Mathematical Model of Short-Term Memory

SIMULATION ◽  
1964 ◽  
Vol 3 (6) ◽  
pp. 46-51
Author(s):  
W. Ross Adey ◽  
N.V. Findler
Keyword(s):  
Electromagnetic Waves ◽  
Short Term Memory ◽  
Threshold Value ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Neuron Density ◽  
Receptor Neurons ◽  
The Brain

It is attempted in this paper to give a mathematical description of the short-term memory. Instead of using the microscopic properties of individual neu rons, such as the number of interconnections, neuron density, threshold value, etc., the cerebral cortex is regarded as a "neuron gas" that is a vast conglomer ate of neurons with statistically distributed charac teristics. Stimuli from the environment cause the receptor neurons to emit virtual electromagnetic waves into the brain. A self-optimizing process of the brain tis sue is here described by which the useful, informa tion-carrying energy reaching the long-term memory tends to maximum. It is emphasized that in the following a brain model is described and the physical processes in volved may have no direct equivalent in reality.

scholarly journals Camelina sativa Methanolic and Ethanolic Extract Potential in Alleviating Oxidative Stress, Memory Deficits, and Affective Impairments in Stress Exposure-Based Irritable Bowel Syndrome Mouse Models

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Roxana O. Cojocariu ◽  
Ioana-Miruna Balmus ◽  
Radu Lefter ◽  
Luminita Hritcu ◽  
Daniela C. Ababei ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Short Term Memory ◽  
Camelina Sativa ◽  
Stress Exposure ◽  
Short Term ◽  
Term Memory ◽  
Maze Test ◽  
Ethanolic Extracts ◽  
Irritable Bowel ◽  
The Brain

Camelina sativa is mainly used as an oilseed crop; its edible oil is being also used as a traditional home remedy for the treatment of ulcers, wounds, and eye inflammations, due to the antioxidant activities. In the present study, the chemically characterized alcoholic extracts of Camelina sativa var. Madalina defatted seeds (5 g/kg body weight p.o., suspended in CMC-Na 0.1%) were administered to stress-induced animal models of irritable bowel syndrome (based on combinations of contention stress and multifactorial stress and maternal stress) and evaluated for the behavioural (short-term memory by the Y maze test, the anxious behaviour using the elevated plus maze test, and the antidepressant effect using the forced swimming test) and brain and bowel tissue oxidative status (superoxide dismutase and glutathione peroxidase enzymes activities and malondialdehyde and total soluble protein levels) improving effects. According to the chemical characterization, the extracts were rich in sinapine, glucosinolates, and flavonol glycosides. Moreover, this study showed the beneficial effects of Camelina sativa seed methanolic and ethanolic extracts on the behaviour and brain and bowel tissues oxidative stress status of stress exposure-based IBS mouse models. Despite the slight differences in the chemical composition of the methanolic and ethanolic extracts, the results suggested that the Camelina sativa extracts could reverse the short-term memory impairments caused by stress exposure and also could decrease the intensity and frequency of the anxiety and depressive-like behaviours observed in the stress-exposed animal models of IBS. Furthermore, the Camelina sativa extracts showed a significant effect on the oxidative stress markers in the brain and bowel tissues of the studied animal model by decreasing the superoxide dismutase activity and increasing the glutathione peroxidase activity. However, the results suggested that the extracts could also increase lipid peroxidation in bowel tissues. In this way, this study provides additional evidence that the administration of Camelina sativa seed alcoholic extracts could improve cognitive performances and mood and exhibit the antioxidant capacity in both the brain and bowel tissues.

Working memory: Unemployed but still doing day labor

2003 ◽  
Vol 26 (6) ◽  
pp. 760-769
Author(s):  
Daniel S. Ruchkin ◽  
Jordan Grafman ◽  
Katherine Cameron ◽  
Rita S. Berndt
Keyword(s):  
Working Memory ◽  
Neural Circuits ◽  
Short Term Memory ◽  
Relevant Information ◽  
Long Term Memory ◽  
Memory Retention ◽  
Short Term ◽  
Term Memory ◽  
Target Article

The goal of our target article is to establish that electrophysiological data constrain models of short-term memory retention operations to schemes in which activated long-term memory is its representational basis. The temporary stores correspond to neural circuits involved in the perception and subsequent processing of the relevant information, and do not involve specialized neural circuits dedicated to the temporary holding of information outside of those embedded in long-term memory. The commentaries ranged from general agreement with the view that short-term memory stores correspond to activated long-term memory (e.g., Abry, Sato, Schwartz, Loevenbruck & Cathiard [Abry etal.], Cowan, Fuster, Grote, Hickok & Buchsbaum, Keenan, Hyönä & Kaakinen [Keenan et al.], Martin, Morra), to taking a definite exception to this view (e.g., Baddeley, Düzel, Logie & Della Sala, Kroger, Majerus, Van der Linden, Colette & Salmon [Majerus et al.], Vallar).

scholarly journals Factors associated with school achievement of children aged 8–10 years in rural Bangladesh: Findings from a post hoc analysis of a community-based study

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254693
Author(s):  
Sheikh Jamal Hossain ◽  
Fahmida Tofail ◽  
Hasan Mahmud Sujan ◽  
Shams El Arifeen ◽  
Jena Hamadani
Keyword(s):  
Short Term Memory ◽  
School Achievement ◽  
Linear Regression Analysis ◽  
Early Age ◽  
Short Term ◽  
Term Memory ◽  
Rural Bangladesh ◽  
Factors Associated ◽  
Wide Range ◽  
Years Of Schooling

Background Education is one of the most important human capitals. Investment in education at early age returns best. A lot of factors influence children’s educational achievement. Studies in developed countries well established the relation of school achievement with its associated variables. But information is lack on what factors play important role for school achievement at early age in low resource settings like Bangladesh. We aimed to find factors associated with school achievement in rural Bangladesh. Method The data were acquired from a long-term follow up study, conducted in 8–10 years old children (n = 372). We used a locally developed school achievement tool based on Wide Range Achievement Test-4 to measure reading, spelling and math computation, Wechsler abbreviated scale of intelligence to measure intelligence Quotient (IQ), Digit span forward and backward for short term memory, and locally available Strength and Difficulties Questionnaire to measure behaviour. Socioeconomic and anthropometric information of the mothers and children were also collected. Multicollinearity of the data was checked. Unadjusted and adjusted multiple linear regression analysis was performed. Findings Years of schooling and short-term memory were positively related to reading, spelling and math computation. For years of schooling it was-reading B = 8.09 (CI 5.84, 10.31), spelling 4.43 (4.33, 8.53) and math computation 5.23 (3.60, 6.87) and for short term memory- reading 3.56 (2.01,5.05), spelling 4.01 (2.56, 5.46) and math computation 2.49 (1.37, 3.62). Older children had lower scores of reading -0.48 (-0.94, -0.02), spelling -0.41 (-0.88, -0.02) and math computation -0.47 (-0.80, -0.14). Children’s IQ predicted reading 0.48 (0.14, 0.81) and spelling 0.50 (0.18, 0.82) skills. Mother and father’s education predicted Spelling 0.82 (0.16, 1.48) and reading 0.68 (0.06, 1.30) capacity respectively. Children enrolled in private schools had higher reading 10.28 (5.05, 15.51) and spelling 6.22 (1.31, 11.13) than those in the government schools. Children with more difficult behaviour tended to have lower scores in reading -0.51 (-0.96, -0.05). Conclusion Children’s school achievement is influenced by their IQ, years of schooling, type of school and parents’ education. Therefore, intervention should be made to focus specifically on these variables and establish the effect of this intervention through robust research design.

scholarly journals Discrete attractor dynamics underlying selective persistent activity in frontal cortex

2017 ◽  
Author(s):  
Hidehiko K. Inagaki ◽  
Lorenzo Fontolan ◽  
Sandro Romani ◽  
Karel Svoboda
Keyword(s):  
Short Term Memory ◽  
Network Modeling ◽  
Motor Planning ◽  
Delayed Response ◽  
Persistent Activity ◽  
Short Term ◽  
Population Activity ◽  
Term Memory ◽  
Attractor Dynamics ◽  
Response Task

AbstractShort-term memories link events separated in time, such as past sensation and future actions. Short-term memories are correlated with selective persistent activity, which can be maintained over seconds. In a delayed response task that requires short-term memory, neurons in mouse anterior lateral motor cortex (ALM) show persistent activity that instructs future actions. To elucidate the mechanisms underlying this persistent activity we combined intracellular and extracellular electrophysiology with optogenetic perturbations and network modeling. During the delay epoch, both membrane potential and population activity of ALM neurons funneled towards discrete endpoints related to specific movement directions. These endpoints were robust to transient shifts in ALM activity caused by optogenetic perturbations. Perturbations occasionally switched the population dynamics to the other endpoint, followed by incorrect actions. Our results are consistent with discrete attractor dynamics underlying short-term memory related to motor planning.

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