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.

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.

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.

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.

Short-Time Tests for Long-Time Endurance

1923 ◽  
Vol 128 (4) ◽  
pp. 264-264
Author(s):  
J. W. Harsch
Keyword(s):  
Long Time ◽  
Short Time

Effect of Vial shaking on Loading Time of Epirubicin into Drug-Eluting Bead

2015 ◽  
Vol 5 (3) ◽  
Author(s):  
Kenji Ikeda ◽  
Yusuke Kawamura ◽  
Masahiro Kobayashi ◽  
Taito Fukushima ◽  
Yushi Sorin ◽  
...  
Keyword(s):  
Antitumor Agent ◽  
Loading Rates ◽  
Vortex Mixer ◽  
Long Time ◽  
Group A ◽  
Drug Eluting ◽  
Large Hepatocellular Carcinoma ◽  
Group B ◽  
Time Required ◽  
Short Time

Background: Although DC Bead has been useful in treatment of multiple and large hepatocellular carcinoma, loading time of doxorubicin into the DC Bead takes a long time of 30-120 minutes. Epirubicin is also used as an antitumor agent together with DC Bead, but its loading efficiency was not sufficiently elucidated. Methods: To shorten loading time of epirubicin into DC Bead (100-300µm, 300-500µm, 500-700µm), we examined the following three methods after mixing the drug: (a) let stand in room temperature, (b) agitated for 30 seconds with Vortex mixer, and (c) sonicated for 30 seconds with ultrasonic cleaner. After loading of epirubicin by each method, supernatant concentration for epirubicin was assayed at 5, 10, 30, 60, and 120 minutes. Results: Epirubicin loading rates for small bead (100-300µm) at 5 minutes were 82.9 % in group a, 93.8% in group b, and 79.9 % in group c. Similarly, medium bead (300-500µm), 40.1% in group a, 65.7% in group b and 45.5% in group c, respectively. In large-sized bead (500-700µm), loaded rates of epirubicin were 38.8% in group a, 59.0% in group b and 48.0% in group c. Agitation of mixture of epirubicin and DC Bead with Vortex mixer significantly shortened the loading time, but sonication did not affect the time required. Microscopic examination did not lead to any morphological change of microspheres in all the methods. Conclusions: Short time of agitation with Vortex mixer reduced the necessary time for loading of epirubicin in every standard of DC Bead.

Robust Test Method of TSOP PEMs for Space Application

2019 ◽  
Author(s):  
Yasunobu Iwai ◽  
Koichi Shinozaki ◽  
Daiki Tanaka
Keyword(s):  
Evaluation Method ◽  
Low Cost ◽  
Reliability Evaluation ◽  
Test Method ◽  
Thermal Shock Test ◽  
Space Application ◽  
Space Applications ◽  
Limit Test ◽  
Long Time ◽  
Short Time

Abstract Compared with space parts, consumer parts are highly functional, low cost, compact and lightweight. Therefore, their increased usage in space applications is expected. Prior testing and evaluation on space applicability are necessary because consumer parts do not have quality guarantees for space application [1]. However, in the conventional reliability evaluation method, the test takes a long time, and the problem is that the robustness of the target sample can’t be evaluated in a short time. In this report, we apply to the latest TSOP PEM (Thin Small Outline Package Plastic Encapsulated Microcircuit) an evaluation method that combines preconditioning and HALT (Highly Accelerated Limit Test), which is a test method that causes failures in a short time under very severe environmental conditions. We show that this method can evaluate the robustness of TSOP PEMs including solder connections in a short time. In addition, the validity of this evaluation method for TSOP PEM is shown by comparing with the evaluation results of thermal shock test and life test, which are conventional reliability evaluation methods.

The Spread of Pollutants from Harbour Sludge Depots

1984 ◽  
Vol 16 (3-4) ◽  
pp. 623-633
Author(s):  
M Loxham ◽  
F Weststrate
Keyword(s):  
Time Scales ◽  
Molecular Diffusion ◽  
Near Field ◽  
Parameter Analysis ◽  
Migration Patterns ◽  
Long Time ◽  
Dilution Effects ◽  
Short Time ◽  
Harbour Sludge

It is generally agreed that both the landfill option, or the civil techniques option for the final disposal of contaminated harbour sludge involves the isolation of the sludge from the environment. For short time scales, engineered barriers such as a bentonite screen, plastic sheets, pumping strategies etc. can be used. However for long time scales the effectiveness of such measures cannot be counted upon. It is thus necessary to be able to predict the long term environmenttal spread of contaminants from a mature landfill. A model is presented that considers diffusion and adsorption in the landfill site and convection and adsorption in the underlaying aquifer. From a parameter analysis starting form practical values it is shown that the adsorption behaviour and the molecular diffusion coefficient of the sludge, are the key parameters involved in the near field. The dilution effects of the far field migration patterns are also illustrated.

Experience with the Relay Procedure for Tuning Controllers in Automatic Control of Chlorination

1993 ◽  
Vol 28 (11-12) ◽  
pp. 257-261
Author(s):  
M. Truett Garrett ◽  
Zaki Ahmad ◽  
Shelly Young
Keyword(s):  
Wastewater Treatment ◽  
Automatic Control ◽  
Time Constant ◽  
Wastewater Treatment Plants ◽  
Relay Feedback ◽  
Quality Of Control ◽  
Incomplete Mixing ◽  
Long Time ◽  
Chlorine Demand

The recent requirements by U.S.E.P.A. for dechlorination and biomonitoring have increased the importance of automatic control of effluent chlorination in wastewater treatment plants. Difficulties with the Ziegler-Nichols controller tuning procedure were reported at the Kyoto Workshop, 1990. Problems are caused by the noise of incomplete mixing, a long time constant, and the disturbances of changing flow and chlorine demand. The Astrom-Hagglund relay feedback procedure provides acceptable control while data is logged to determine the controller constants. Experiences in using the procedure in existing facilities (not redesigning the mixing point) and the quality of control are presented.

Alteration of intrapancreatic serotonin, homocysteine, TNF-α, and NGF levels as predisposing factors for diabetes following exposure to 900-MHz waves

2021 ◽  
pp. 074823372110226
Author(s):  
Gholamali Jelodar ◽  
Mansour Azimzadeh ◽  
Fatemeh Radmard ◽  
Narges Darvishhoo
Keyword(s):  
Cell Damage ◽  
Pancreatic Beta Cell ◽  
Predisposing Factors ◽  
Male Rats ◽  
Control Group ◽  
Predisposing Factor ◽  
Time Exposure ◽  
Tnf Α ◽  
Long Time ◽  
Short Time

Exposure to mobile phone radiation causes deleterious health effects on biological systems. The objects of this study were to investigate the effect of 900-MHz radiofrequency waves (RFW) emitted from base transceiver station antenna on intrapancreatic homocysteine (Hcy), tumor necrosis factor-α (TNF-α), and nerve growth factor (NGF) as predisposing factors involved in pancreatic beta cell damage. Thirty male rats (Sprague-Dawley, 200 ± 10 g) were randomly divided into the control (without any exposure) and exposed groups: short time (2 h/day), long time (4 h/day), and exposed to 900-MHz RFW for 30 consecutive days. On the last days of the experiment, animals were killed and pancreas tissue was dissected out for evaluation of serotonin, Hcy, TNF-α, and NGF. There was a significant decrease in the serotonin and NGF levels in the pancreatic tissue of exposed groups compared to the control group ( p < 0.05). Also, the levels of serotonin and NGF in the long-time exposure were significantly lower than the short-time exposure ( p < 0.05). However, levels of Hcy and TNF-α were significantly increased in the pancreas of exposed groups compared to the control groups ( p < 0.05). Exposure to 900-MHz RFW decreased pancreatic NGF and serotonin levels and increased the proinflammatory markers (Hcy and TNF-α), which can be a predisposing factor for type 2 diabetes.

Sign in / Sign up

Export Citation Format

Share Document