Unconventional Computing

1998 ◽  
Author(s):  
Christof Koch
Keyword(s):  
Fluorescent Dyes ◽  
Short Term Memory ◽  
Electrical Potential ◽  
Cortical Cell ◽  
Mathematical Operation ◽  
Vast Number ◽  
Calcium Dependent ◽  
Free Intracellular Calcium ◽  
The Brain ◽  
And Diffusion

As discussed in the introduction to this book, any (bio)physical mechanism that transforms some physical variable, such as the electrical potential across the membrane, in such a way that it can be mapped onto a meaningful formal mathematical operation, such as delayand- correlate or convolution, can be treated as a computation. Traditionally only Vm, spike trains, and the firing rate f(t) have been thought to play this role in the computations performed by the nervous system. Due to the recent and widespread usage of high-resolution calcium-dependent fluorescent dyes, the concentration of free intracellular calcium [Ca2+]i in presynaptic terminals, dendrites, and cell bodies has been promoted into the exalted rank of a variable that can act as a short-term memory and that can be manipulated using buffers, calcium-dependent enzymes, and diffusion in ways that can be said to instantiate specific computations. But why stop here? Why not consider the vast number of signaling molecules that are localized to specific intra- or extracellular compartments to instantiate specific computations that can act over particular spatial and temporal time scales? And what about the peptides and hormones that are released into large areas of the brain or that circulate in the bloodstream? In this penultimate chapter, we will acquaint the reader with several examples of computations that use such unconventional means. The computation in question constitutes a molecular switch that stores a few bits of information at each of the thousands of synapses on a typical cortical cell. In order to describe its principle of operation, it will be necessary to introduce the reader to some basic concepts in biochemistry. The ability of individual synapses to potentially store analog variables is important enough that this modest intellectual investment will pay off. (For an introduction to biochemistry, consult Stryer, 1995).

The Acute Effect of Alcohol on Various Memory Processes

2010 ◽  
Vol 24 (4) ◽  
pp. 249-252 ◽  
Author(s):  
Márk Molnár ◽  
Roland Boha ◽  
Balázs Czigler ◽  
Zsófia Anna Gaál
Keyword(s):  
Low Dose ◽  
Short Term Memory ◽  
Acute Effect ◽  
Long Term Memory ◽  
Term Memory ◽  
Memory Processes ◽  
Different Types ◽  
The Brain ◽  
Legal Consequences

This review surveys relevant and recent data of the pertinent literature regarding the acute effect of alcohol on various kinds of memory processes with special emphasis on working memory. The characteristics of different types of long-term memory (LTM) and short-term memory (STM) processes are summarized with an attempt to relate these to various structures in the brain. LTM is typically impaired by chronic alcohol intake but according to some data a single dose of ethanol may have long lasting effects if administered at a critically important age. The most commonly seen deleterious acute effect of alcohol to STM appears following large doses of ethanol in conditions of “binge drinking” causing the “blackout” phenomenon. However, with the application of various techniques and well-structured behavioral paradigms it is possible to detect, albeit occasionally, subtle changes of cognitive processes even as a result of a low dose of alcohol. These data may be important for the consideration of legal consequences of low-dose ethanol intake in conditions such as driving, etc.

scholarly journals A new image encryption algorithm based on the OF-LSTMS and chaotic sequences

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yi He ◽  
Ying-Qian Zhang ◽  
Xin He ◽  
Xing-Yuan Wang
Keyword(s):  
Image Encryption ◽  
Fractional Order ◽  
Chaotic System ◽  
Short Term Memory ◽  
Encryption Algorithm ◽  
Chaotic Sequences ◽  
Long Short Term Memory ◽  
Input Gate ◽  
And Diffusion ◽  
Image Encryption Algorithm

AbstractIn this paper, a novel image encryption algorithm based on the Once Forward Long Short Term Memory Structure (OF-LSTMS) and the Two-Dimensional Coupled Map Lattice (2DCML) fractional-order chaotic system is proposed. The original image is divided into several image blocks, each of which is input into the OF-LSTMS as a pixel sub-sequence. According to the chaotic sequences generated by the 2DCML fractional-order chaotic system, the parameters of the input gate, output gate and memory unit of the OF-LSTMS are initialized, and the pixel positions are changed at the same time of changing the pixel values, achieving the synchronization of permutation and diffusion operations, which greatly improves the efficiency of image encryption and reduces the time consumption. In addition the 2DCML fractional-order chaotic system has better chaotic ergodicity and the values of chaotic sequences are larger than the traditional chaotic system. Therefore, it is very suitable to image encryption. Many simulation results show that the proposed scheme has higher security and efficiency comparing with previous schemes.

scholarly journals Characterization of calcium-dependent membrane binding proteins of brain cortex

1985 ◽  
Vol 229 (3) ◽  
pp. 587-593 ◽  
Author(s):  
A R Rhoads ◽  
M Lulla ◽  
P B Moore ◽  
C E Jackson
Keyword(s):  
Brain Cortex ◽  
Peptide Mapping ◽  
Bovine Brain ◽  
Particulate Fraction ◽  
Structural Homology ◽  
One Dimensional ◽  
Calcium Dependent ◽  
Stokes Radius ◽  
The Brain

Proteins of Mr 68 000, 34 000 and 32 000 were selectively extracted by EGTA from brain cortex. The three proteins that were extracted along with calmodulin were acidic, monomeric, and did not exhibit structural homology, as demonstrated by one-dimensional peptide mapping. The Mr-68 000 protein was purified to homogeneity and had a Stokes radius of 3.54 nm and S20,W value of 5.1S. Purified calmodulin, Mr-68 000 protein and two proteins of Mr 34 000 and Mr 32 000, interacted with the brain particulate fraction, with half-maximal binding occurring at 3.5 microM, 8.3 microM and 150 microM-Ca2+ respectively. Proteins were bound independently of each other and calmodulin. Pretreatment of the particulate fraction with trypsin prevented the Ca2+-dependent binding of calmodulin; however, the binding of the Mr-68 000 protein or the Mr−32 000 and −34 000 proteins was unaffected. The Mr-68 000 protein of bovine brain did not cross-react immunologically with Mr-67 000 calcimedin from chicken gizzard.

Variables That Influence the Generation of Random Sequences: An Update

1997 ◽  
Vol 84 (2) ◽  
pp. 627-661 ◽  
Author(s):  
Peter Brugger
Keyword(s):  
Short Term Memory ◽  
Human Subjects ◽  
Complete Suppression ◽  
Random Generation ◽  
Short Term ◽  
Random Sequences ◽  
Potential Applications ◽  
Basic Experiments ◽  
The Brain ◽  
Relevant Work

This article updates Tune's 1964 review of variables influencing human subjects' attempts at generating random sequences of alternatives. It also covers aspects not included in the original review such as randomization behavior by patients with neurological and psychiatric disorders. Relevant work from animal research (spontaneous alternation paradigm) is considered as well. It is conjectured that Tune's explanation of sequential nonrandomness in terms of a limited capacity of short-term memory can no longer be maintained. Rather, interdependence among consecutive choices is considered a consequence of an organism's natural susceptibility to interference. Random generation is thus a complex action which demands complete suppression of any rule-governed behavior. It possibly relies on functions of the frontal lobes but cannot otherwise be “localized” to restricted regions of the brain. Possible developments in the field are briefly discussed, both with respect to basic experiments regarding the nature of behavioral nonrandomness and to potential applications of random-generation tasks.

Calmodulin levels in hypertensive rats

1985 ◽  
Vol 68 (4) ◽  
pp. 407-410 ◽  
Author(s):  
J. Higaki ◽  
T. Ogihara ◽  
Y. Kumahara ◽  
E. L. Bravo
Keyword(s):  
Intracellular Calcium ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Deoxycorticosterone Acetate ◽  
Spontaneously Hypertensive ◽  
Calcium Dependent ◽  
Wistar Kyoto Rats ◽  
Regulatory Systems ◽  
Wistar Kyoto ◽  
The Brain

1. Intracellular calmodulin levels were measured by direct radioimmunoassay in spontaneously hypertensive rats (SHR) and Wistar—Kyoto rats (WKY). 2. Decreased calmodulin levels were demonstrated in the brain, heart, aorta and kidney of spontaneously hypertensive rats compared with those in Wistar—Kyoto rats. 3. Calmodulin levels in the brain were also decreased in deoxycorticosterone acetate (DOCA)-salt rats, but not changed significantly in the heart, aorta and kidney compared with those in Wistar—Kyoto rats. 4. These findings suggest that intracellular calcium-dependent regulatory systems are genetically disrupted in spontaneously hypertensive rats, but this is probably not an important factor in the development of hypertension.

Diffusion, Buffering, and Binding

1998 ◽  
Author(s):  
Christof Koch
Keyword(s):  
Synaptic Plasticity ◽  
Intracellular Calcium ◽  
Temporal Dynamics ◽  
Critical Concentration ◽  
Two Photon Microscopy ◽  
Calcium Dependent ◽  
Calcium Sensors ◽  
Free Intracellular Calcium ◽  
Messenger Molecules ◽  
Spatio Temporal

In Chap. 9 we introduced calcium ions and alluded to their crucial role in regulating the day-to-day life of neurons. The dynamics of the free intracellular calcium is controlled by a number of physical and chemical processes, foremost among them diffusion and binding to a host of different proteins, which serve as calcium buffers and as calcium sensors or triggers. Whereas buffers simply bind Ca2+ above some critical concentration, releasing it back into the cytoplasm when [Ca2+]i has been reduced below this level, certain proteins— such as calmodulin—change their conformation when they bind with Ca2+ ions, thereby activating or modulating enzymes, ionic channels, or other proteins. The calcium concentration inside the cell not only determines the degree of activation of calcium-dependent potassium currents but—much more importantly—is relevant for determining the changes in structure expressed in synaptic plasticity. As discussed in Chap. 13, it is these changes that are thought to underlie learning. Given the relevance of second messenger molecules, such as Ca2+, IP3, cyclic AMP and others, for the processes underlying growth, sensory adaptation, and the establishment and maintenance of synaptic plasticity, it is crucial that we have some understanding of the role that diffusion and chemical kinetics play in governing the behavior of these substances. Today, we have unprecedented access to the spatio-temporal dynamics of intracellular calcium in individual neurons using fluorescent calcium dyes, such as fura-2 or fluo-3, in combination with confocal or two-photon microscopy in the visible or in the infrared spectrum (Tsien, 1988; Tank et al., 1988; Hernández-Cruz, Sala, and Adams, 1990; Ghosh and Greenberg, 1995).

scholarly journals MRI Brain Classification Using the Quantum Entropy LBP and Deep-Learning-Based Features

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 1033
Author(s):  
Ali M. Hasan ◽  
Hamid A. Jalab ◽  
Rabha W. Ibrahim ◽  
Farid Meziane ◽  
Ala’a R. AL-Shamasneh ◽  
...  
Keyword(s):  
Deep Learning ◽  
Brain Tumor ◽  
Short Term Memory ◽  
Local Binary Patterns ◽  
Quantum Entropy ◽  
Brain Scans ◽  
Quantum Calculus ◽  
Mri Brain ◽  
Brain Scan ◽  
The Brain

Brain tumor detection at early stages can increase the chances of the patient’s recovery after treatment. In the last decade, we have noticed a substantial development in the medical imaging technologies, and they are now becoming an integral part in the diagnosis and treatment processes. In this study, we generalize the concept of entropy difference defined in terms of Marsaglia formula (usually used to describe two different figures, statues, etc.) by using the quantum calculus. Then we employ the result to extend the local binary patterns (LBP) to get the quantum entropy LBP (QELBP). The proposed study consists of two approaches of features extractions of MRI brain scans, namely, the QELBP and the deep learning DL features. The classification of MRI brain scan is improved by exploiting the excellent performance of the QELBP–DL feature extraction of the brain in MRI brain scans. The combining all of the extracted features increase the classification accuracy of long short-term memory network when using it as the brain tumor classifier. The maximum accuracy achieved for classifying a dataset comprising 154 MRI brain scan is 98.80%. The experimental results demonstrate that combining the extracted features improves the performance of MRI brain tumor classification.

scholarly journals Short-Term Memory Deficits in the SLEEP Inbred Panel

2019 ◽  
Vol 1 (4) ◽  
pp. 471-488 ◽  
Author(s):  
Shailesh Kumar ◽  
Kirklin R. Smith ◽  
Yazmin L. Serrano Negron ◽  
Susan T. Harbison
Keyword(s):  
Learning And Memory ◽  
Sleep Duration ◽  
Genetic Architecture ◽  
Short Term Memory ◽  
Morphological Changes ◽  
Brain Structures ◽  
Social Conditions ◽  
Short Term ◽  
The Relationship ◽  
The Brain

Although sleep is heritable and conserved across species, sleep duration varies from individual to individual. A shared genetic architecture between sleep duration and other evolutionarily important traits could explain this variability. Learning and memory are critical traits sharing a genetic architecture with sleep. We wanted to know whether learning and memory would be altered in extreme long or short sleepers. We therefore assessed the short-term learning and memory ability of flies from the Sleep Inbred Panel (SIP), a collection of 39 extreme long- and short-sleeping inbred lines of Drosophila. Neither long nor short sleepers had appreciable learning, in contrast to a moderate-sleeping control. We also examined the response of long and short sleepers to enriched social conditions, a paradigm previously shown to induce morphological changes in the brain. While moderate-sleeping control flies had increased daytime sleep and quantifiable increases in brain structures under enriched social conditions, flies of the Sleep Inbred Panel did not display these changes. The SIP thus emerges as an important model for the relationship between sleep and learning and memory.

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