scholarly journals Repetitive firing: quantitative analysis of encoder behavior of slowly adapting stretch receptor of crayfish and eccentric cell of Limulus.

1977 ◽  
Vol 69 (6) ◽  
pp. 849-877 ◽  
Author(s):  
J F Fohlmeister ◽  
R E Poppele ◽  
R L Purple
Keyword(s):  
Time Constant ◽  
Sodium Pump ◽  
Cell Types ◽  
Stretch Receptor ◽  
The Other ◽  
Repetitive Firing ◽  
Electrogenic Sodium Pump ◽  
Leaky Integrator ◽  
Long Time ◽  
Short Time

Techniques developed for determining summed encoder feedback in conjunction with the leaky integrator and variable-gamma models for repetitive firing are applied to spike train data obtained from the slowly adapting crustacean stretch receptor and the eccentric cell of Limulus. Input stimuli were intracellularly applied currents. Analysis of data from cells stringently selected by reproducibility criteria gave a consistent picture for the dynamics of repetitive firing. The variable-gamma model with appropriate summed feedback was most accurate for describing encoding behavior of both cell types. The leaky integrator model, while useful for determining summed feedback parameters, was inadequate to account for underlying mechanisms of encoder activity. For the stretch receptor, two summed feedback processes were detected: one had a short time constant; the other, a long one. Appropriate tests indicated that the short time constant effect was from an electrogenic sodium pump, and the same is presumed for the long time constant summed feedback. Both feedbacks show seasonal and/or species variations. Short hyperpolarizing pulses inhibited the feedback from the long time constant process. The eccentric cell also showed two summed feedback processes: one is due to self inhibition, the other is postulated to be a short time constant electrogenic sodium pump similar to that described in the stretch receptor.

scholarly journals A sensory integration account for time perception

2020 ◽  
Author(s):  
Alessandro Toso ◽  
Arash Fassihi ◽  
Luciano Paz ◽  
Francesca Pulecchi ◽  
Mathew E. Diamond
Keyword(s):  
Time Perception ◽  
Time Constant ◽  
Sensory Integration ◽  
Neuronal Firing ◽  
Elapsed Time ◽  
Leaky Integrator ◽  
Long Time ◽  
Integrator Model ◽  
Short Time ◽  
Sense Of Touch

ABSTRACTThe connection between stimulus perception and time perception remains unknown. The present study combines human and rat psychophysics with sensory cortical neuronal firing to construct a computational model for the percept of elapsed time embedded within sense of touch. When subjects judged the duration of a vibration applied to the fingertip (human) or whiskers (rat), increasing stimulus mean speed led to increasing perceived duration. Symmetrically, increasing vibration duration led to increasing perceived intensity. We modeled spike trains from vibrissal somatosensory cortex as input to dual leaky integrators – an intensity integrator with short time constant and a duration integrator with long time constant – generating neurometric functions that replicated the actual psychophysical functions of rats. Returning to human psychophysics, we then confirmed specific predictions of the dual leaky integrator model. This study offers a framework, based on sensory coding and subsequent accumulation of sensory drive, to account for how a feeling of the passage of time accompanies the tactile sensory experience.

scholarly journals A sensory integration account for time perception

2021 ◽  
Vol 17 (1) ◽  
pp. e1008668
Author(s):  
Alessandro Toso ◽  
Arash Fassihi ◽  
Luciano Paz ◽  
Francesca Pulecchi ◽  
Mathew E. Diamond
Keyword(s):  
Time Perception ◽  
Time Constant ◽  
Sensory Integration ◽  
Neuronal Firing ◽  
Elapsed Time ◽  
Leaky Integrator ◽  
Long Time ◽  
Integrator Model ◽  
Short Time ◽  
Sense Of Touch

The connection between stimulus perception and time perception remains unknown. The present study combines human and rat psychophysics with sensory cortical neuronal firing to construct a computational model for the percept of elapsed time embedded within sense of touch. When subjects judged the duration of a vibration applied to the fingertip (human) or whiskers (rat), increasing stimulus intensity led to increasing perceived duration. Symmetrically, increasing vibration duration led to increasing perceived intensity. We modeled real spike trains recorded from vibrissal somatosensory cortex as input to dual leaky integrators–an intensity integrator with short time constant and a duration integrator with long time constant–generating neurometric functions that replicated the actual psychophysical functions of rats. Returning to human psychophysics, we then confirmed specific predictions of the dual leaky integrator model. This study offers a framework, based on sensory coding and subsequent accumulation of sensory drive, to account for how a feeling of the passage of time accompanies the tactile sensory experience.

Lessons From an Operational Small Leakage at Tsuruga Nuclear Power Station

2015 ◽  
Author(s):  
Hiroyuki Kobayashi ◽  
Osamu Urabe ◽  
Takushi Fujino
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power Station ◽  
Nuclear Power ◽  
The Other ◽  
Leak Test ◽  
Power Station ◽  
Long Time ◽  
Short Time ◽  
Repair Techniques

Operational small leakage is occasionally observed in a nuclear power plant, and the leak forces an operator to decide whether to shut down the plant or not. Even if the leakage is just a little, it might draw the considerable attention in the society, so that the operator sometimes gets into the situation to judge more severely than technical judgment. Furthermore, at the time of plant restart and the system leak test just after maintenance, even the operator doesn’t accept any leakage considering the long management for the leakage up to the next outage. On the other hand, once the operator shut down the plant, it sometimes takes long time to restart again because of the difficulty to obtain new pipes and valves in short time. The temporary repair techniques referred to the JSME code might be able to be applied to maintain the plant operation, however some difficulties exist in a practical process. One of the authors has faced with many cases in which the operational small leakage had to be dealt at Tsuruga nuclear power station. This paper shows some cases of them and discusses lessons which are related to the codes and standards.

Inhibition of Afferent Transmission in the Feeding Circuitry of Aplysia: Persistence Can Be as Important as Size

2005 ◽  
Vol 93 (5) ◽  
pp. 2940-2949 ◽  
Author(s):  
Colin G. Evans ◽  
Adarli Romero ◽  
Elizabeth C. Cropper
Keyword(s):  
Time Constant ◽  
Synaptic Input ◽  
Low Frequencies ◽  
Lateral Process ◽  
Postsynaptic Potentials ◽  
Inhibitory Postsynaptic Potentials ◽  
Functional Inhibition ◽  
Long Time ◽  
Spike Initiation ◽  
Short Time

We are studying afferent transmission from a mechanoafferent, B21, to a follower, B8. During motor programs, afferent transmission is regulated so that it does not always occur. Afferent transmission is eliminated when spike propagation in B21 fails, i.e., when spike initiation is inhibited in one output region-B21's lateral process. Spike initiation in the lateral process is inhibited by the B52 and B4/5 cells. Individual B52 and B4/5-induced inhibitory postsynaptic potentials (IPSPs) in B21 differ. For example, the peak amplitude of a B4/5-induced IPSP is four times the amplitude of a B52 IPSP. Nevertheless, when interneurons fire in bursts at physiological (i.e., low) frequencies, afferent transmission is most effectively reduced by B52. Although individual B52-induced IPSPs are small, they have a long time constant and summate at low firing frequencies. Once IPSPs summate, they effectively block afferent transmission. In contrast, individual B4/5-induced IPSPs have a relatively short time constant and do not summate at low frequencies. B52 and B4/5 therefore differ in that once synaptic input from B52 becomes effective, afferent transmission is continuously inhibited. In contrast, periods of B4/5-induced inhibition are interspersed with relatively long intervals in which inhibition does not occur. Consequently, the probability that afferent transmission will be inhibited is low. In conclusion, it is widely recognized that afferent transmission can be regulated by synaptic input. Our experiments are, however, unusual in that they relate specific characteristics of postsynaptic potentials to functional inhibition. In particular we demonstrate the potential importance of the IPSP time constant.

scholarly journals The Role of Memory in the Perception of the Screen Image

2012 ◽  
Vol 4 (2-3) ◽  
pp. 96-105
Author(s):  
Vitaly Fyodorovich Poznin
Keyword(s):  
Human Memory ◽  
The Other ◽  
Screen Image ◽  
Other Hand ◽  
Different Types ◽  
Long Time ◽  
Short Time ◽  
Artistic Image ◽  
Psychology Of Art

The article investigates one of the aspects of psychology of art, namely, the role of different types of human memory — sensory, long-time, short-time — in the forming of an artistic image in the perception of an audiovisual entity. The audience’s perception of such specific cinematic methods as pan shot and dolly shot, as well as different types of parallel, associative and distance montage rests on the peculiarities of our short-time and long-time memory. On the other hand, the complex polyphonic combination of various visual chronotopes in modern films is based on the imitation of memory typical for our dreams.

The Consequences of Indo-Pakistani War for Urdu Language and Literature: A Parting of the Ways?

1969 ◽  
Vol 28 (2) ◽  
pp. 269-283 ◽  
Author(s):  
C. M. Naim
Keyword(s):  
United Nations ◽  
The Other ◽  
General Area ◽  
Military Logistics ◽  
Language And Literature ◽  
The Future ◽  
Long Time ◽  
The United Nations ◽  
Short Time ◽  
Parting Of The Ways

In September 1965, there occurred between the armies of India and Pakistan a fierce clash which each side attributed to the aggressive designs of the other. This undeclared war lasted only a short time; first a ceasefire ordered by the United Nations, and later the pact signed at Tashkent, brought the hostilities to a formal close. It was by no means a spontaneous or unexpected flareup, the hatred and antagonism that caused it had been festering for a long time. Similarly, its effects have not been short-lived; neither have they been restricted to the area of military logistics and high diplomacy. In this paper I intend to review the consequences of that conflict for Urdu language and literature. I shall proceed by showing why it was necessary for Urdu writers, especially the poets, to respond to this war, and what sort of attitudes were displayed in the poetry written exclusively in response to it. I shall then discuss certain subsequent developments in the general area of Urdu language and literature and end by presenting my own conclusions with regard to the future.

Suppression of Optokinetic Velocity Storage in Humans by Static Tilt in Pitch

1990 ◽  
Vol 1 (1) ◽  
pp. 39-48
Author(s):  
S.H. Lafortune ◽  
D.J. Ireland ◽  
R.M. Jell
Keyword(s):  
Time Constant ◽  
Component Model ◽  
Velocity Storage ◽  
Indirect Pathway ◽  
Otolith Organ ◽  
Optokinetic Afternystagmus ◽  
Slow Decay ◽  
Two Component ◽  
Long Time ◽  
Short Time

The effects of static tilts about the pitch axis on human horizontal optokinetic afternystagmus OKAN (HOKAN) were examined. Static tilts in pitch produced tilt-dependent HOKAN suppression. The slow decay (indirect pathway) component (coefficient C and long time constant 1/D) of the two-component model for OKAN was significantly reduced, while the short decay (direct pathway) component (coefficient A and short time constant 1/B) remained invariant as angle of tilt was increased. These results provide further evidence that otolith organ activity can couple to horizontal velocity storage in humans; in accordance with models proposed in the literature.

scholarly journals . Effect of fluoxetine on the inhibition of adenylate cyclase activity in foskolin-stimulated MLTC-1 leydig cells

2020 ◽  
Vol 17 (4) ◽  
pp. 595-602
Author(s):  
Nguyen Thi Mong Diep ◽  
Nguyen Thi Bich Hang ◽  
Nguyen Le Cong Minh ◽  
Tran Thanh Son ◽  
Nguyen Thuy Duong
Keyword(s):  
Cyclic Amp ◽  
Leydig Cells ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cell Types ◽  
Intracellular Camp ◽  
Atp Levels ◽  
Long Time ◽  
Short Time ◽  
Camp Levels

Fluoxetine (FLX), a widely used antidepressant primarily acting as a selective serotonin reuptake inhibitor, has been shown to exhibit other mechanisms of action in various cell types. Cyclic adenosine monophosphate (cAMP) is a second messenger used for intracellular signal induction. Cyclic AMP is a nucleotide synthesized within the cell from adenosine triphosphate by the adenylyl cyclase enzyme, and is inactivated enzymatically to 5′AMP by hydroxylation with a group of enzymes called phosphodiesterase. The aim of this study was to determine the effects of FLX on MLTC-1 Leydig cells on intracellular cyclic AMP response to forskolin (FSK). MLTC-1 cells were incubated at 37°C in media supplemented with or without different doses of FLX (0, 0.156, 0.3125, 0.625, 1.25, 2.5, 5 and 10 µM). We then looked for how the concentration of FLX for a short-time (2 hours) and a long-time (24 hours) affects the concentration of intracellular cyclic AMP response to FSK and ATP levels on MLTC-1 cells. Our results show that FLX decreased the intracellular cAMP response to FSK depending on FLX concentration. FLX decreased significantly cAMP levels only at 10 µM after 2 hours of incubation but after 24 hours of incubation FLX caused an effect on cAMP levels at 5 µM and at 10 µM. Moreover, as expected, FLX also caused a decline of steroidogenesis, which is under the control of cAMP and ATP levels in the cells. Taken together, these findings demonstrate that the inhibition of cAMP synthesis by FLX is dose-dependent, and that FLX also inhibited hormone-induced steroidogenesis in MLTC-1 cells.

scholarly journals Functional roles of Kv1-mediated currents in genetically identified subtypes of pyramidal neurons in layer 5 of mouse somatosensory cortex

2018 ◽  
Vol 120 (2) ◽  
pp. 394-408 ◽  
Author(s):  
Dongxu Guan ◽  
Dhruba Pathak ◽  
Robert C. Foehring
Keyword(s):  
Subcellular Localization ◽  
Action Potentials ◽  
Pyramidal Neurons ◽  
Cell Types ◽  
The Other ◽  
Repetitive Firing ◽  
Biophysical Properties ◽  
Whole Cell ◽  
Expression Levels ◽  
Similar Expression

We used voltage-clamp recordings from somatic outside-out macropatches to determine the amplitude and biophysical properties of putative Kv1-mediated currents in layer 5 pyramidal neurons (PNs) from mice expressing EGFP under the control of promoters for etv1 or glt. We then used whole cell current-clamp recordings and Kv1-specific peptide blockers to test the hypothesis that Kv1 channels differentially regulate action potential (AP) voltage threshold, repolarization rate, and width as well as rheobase and repetitive firing in these two PN types. We found that Kv1-mediated currents make up a similar percentage of whole cell K+ current in both cell types, and only minor biophysical differences were observed between PN types or between currents sensitive to different Kv1 blockers. Putative Kv1 currents contributed to AP voltage threshold in both PN types, but AP width and rate of repolarization were only affected in etv1 PNs. Kv1 currents regulate rheobase, delay to the first AP, and firing rate similarly in both cell types, but the frequency-current slope was much more sensitive to Kv1 block in etv1 PNs. In both cell types, Kv1 block shifted the current required to elicit an onset doublet of action potentials to lower currents. Spike frequency adaptation was also affected differently by Kv1 block in the two PN types. Thus, despite similar expression levels and minimal differences in biophysical properties, Kv1 channels differentially regulate APs and repetitive firing in etv1 and glt PNs. This may reflect differences in subcellular localization of channel subtypes or differences in the other K+ channels expressed. NEW & NOTEWORTHY In two types of genetically identified layer 5 pyramidal neurons, α-dendrotoxin blocked approximately all of the putative Kv1 current (on average). We used outside-out macropatches and whole cell recordings at 33°C to show that despite similar expression levels and minimal differences in biophysical properties, Kv1 channels differentially regulate action potentials and repetitive firing in etv1 and glt pyramidal neurons. This may reflect differences in subcellular localization of channel subtypes or differences in the other K+ channels expressed.

Fair enumeration combinators

2017 ◽  
Vol 27 ◽  
Author(s):  
MAX S. NEW ◽  
BURKE FETSCHER ◽  
ROBERT BRUCE FINDLER ◽  
JAY MCCARTHY
Keyword(s):  
Programming Language ◽  
Time Scales ◽  
Ad Hoc ◽  
The Other ◽  
Language Models ◽  
Natural Numbers ◽  
Random Generator ◽  
Long Time ◽  
Short Time ◽  
Better Than

AbstractEnumerations represented as bijections between the natural numbers and elements of some given type have recently garnered interest in property-based testing because of their efficiency and flexibility. There are, however, many ways of defining these bijections, some of which are better than others. This paper offers a new property of enumeration combinators called fairness that identifies enumeration combinators that are better suited to property-based testing. Intuitively, the result of a fair combinator indexes into its argument enumerations equally when constructing its result. For example, extracting the nth element from our enumeration of three-tuples indexes about $\sqrt[3]{n}$ elements into each of its components instead of, say, indexing $\sqrt[2]{n}$ into one and $\sqrt[4]{n}$ into the other two, as you would if a three-tuple were built out of nested pairs. Similarly, extracting the nth element from our enumeration of a three-way union returns an element that is $\frac{n}{3}$ into one of the argument enumerators. The paper presents a semantics of enumeration combinators, a theory of fairness, proofs establishing fairness of our new combinators and that some combinations of fair combinators are not fair. We also report on an evaluation of fairness for the purpose of finding bugs in programming-language models. We show that fair enumeration combinators have complementary strengths to an existing, well-tuned ad hoc random generator (better on short time scales and worse on long time scales) and that using unfair combinators is worse across the board.

Sign in / Sign up

Export Citation Format

Share Document