The spatiotemporal transfer function of crayfish lamina monopolar neurons

1994 ◽  
Vol 71 (6) ◽  
pp. 2168-2182 ◽  
Author(s):  
R. M. Glantz ◽  
A. Bartels
Keyword(s):  
Time Course ◽  
Transfer Functions ◽  
Temporal Frequency ◽  
Sine Wave ◽  
Orientation Preference ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Band Pass ◽  
Sensitivity Profile

1. The graded, synaptic potentials of first-order visual interneurons (lamina monopolar cells) were examined with intracellular recordings. The spatiotemporal properties were characterized with drifting sine wave gratings and annuli. 2. Annulus-elicited inhibition is maximal for annulus-test pulse intervals of approximately 140 ms and declines exponentially. The inhibition declines with increasing annular internal radii (ri). 3. Grating responses were examined with respect to spatial and temporal frequency. The gratings elicit sinusoidal signals that are approximately linear with contrast. 4. Variations in spatial frequency produce response functions with a low-pass or modest band-pass characteristic, which are described by a difference of Gaussians sensitivity profile. The central Gaussian approximates the sensitivity profile of photoreceptors. The inhibitory Gaussian is similar to the inhibitory field estimated with annulus pulses. The peak of the inhibitory Gaussian is approximately 18% of the peak excitatory Gaussian. 5. Variations in temporal frequency generally produce transfer functions with a band-pass characteristic and a peak at 1.0 Hz. These data were described by a difference of exponentials function convolved with a low-pass filter that approximates the photoreceptor response. The inhibitory time course estimated from these data was similar to that of the annulus measurements. 6. The spatiotemporal properties of lateral inhibition are consistent with inhibitory action by the lamina amacrine neurons. The proposed model is spatiotemporally inseparable and nonrecurrent. 7. Eleven of 20 monopolar cells tested exhibited a strong orientation preference with a bias to the vertical. Photoreceptors exhibit little or no orientation preference.

Dynamics of neurons in the cat lateral geniculate nucleus: in vivo electrophysiology and computational modeling

1995 ◽  
Vol 74 (3) ◽  
pp. 1222-1243 ◽  
Author(s):  
P. Mukherjee ◽  
E. Kaplan
Keyword(s):  
Computational Modeling ◽  
Spike Train ◽  
Lateral Geniculate Nucleus ◽  
Transfer Functions ◽  
Temporal Frequency ◽  
Relay Cell ◽  
Lateral Geniculate ◽  
Low Pass ◽  
Band Pass

1. We investigated the time domain transformation that thalamocortical relay cells of the cat lateral geniculate nucleus (LGN) perform on their retinal input, and used computational modeling to explore the biophysical properties that determine the dynamics of the LGN relay cells in vivo. 2. We recorded simultaneously the input (S potentials) and output (action potentials) of 50 cat LGN relay cells stimulated by drifting sinusoidal gratings of varying temporal frequency. The temporal modulation transfer functions (TMTFs) of the neurons were derived from these data. The burstiness of the LGN spike trains was also assessed using objective criteria. 3. We found that the form of the TMTF was quite variable among cells, ranging from low-pass to strongly band-pass. The optimal temporal frequency of band-pass neurons was between 2 and 8 Hz. In addition, the TMTF of some cells was nonstationary: their temporal tuning changed with time. 4. The temporal tuning of a cell was directly related to the degree of burstiness of its spike train. Tonically firing relay cells had low-pass TMTFs, whereas the most bursty neurons exhibited the most sharply band-pass transfer functions. This was also true for single cells that altered their temporal tuning: a shift to more band-pass tuning was associated with increased burstiness of the spike train, and vice versa. 5. We constructed a computer simulation of the LGN relay cell. The model was a simplified five-channel version of the thalamocortical neuron model of McCormick and Huguenard. It incorporated the quantitative kinetics of the Ca2+ T channel, as well as the Hodgkin-Huxley Na+ and K+ channels, as the only active membrane currents. To simulate the in vivo dynamics of the relay cell, the input to the model consisted of trains of synaptic potentials, recorded as S potentials in our physiological experiments. 6. When the resting membrane potential of the model neuron was relatively depolarized, the model's TMTF was low-pass, with no bursting evident in the simulated spike train. At hyperpolarized resting membrane potentials, however, the modeled TMTF was band-pass, with frequent burst discharges. Thus the biophysical model reproduced not only the range of dynamics seen in real LGN relay cells, but also the dependence of the overall dynamics on the burstiness of the spike train. However, neither of these phenomena could be simulated without the T channel. Thus the simulations demonstrated that the T-type Ca2+ channel was necessary and sufficient to explain the LGN dynamics observed in physiological experiments.(ABSTRACT TRUNCATED AT 400 WORDS)

Processing Load Signal on Wheel Loader Transmission

2011 ◽  
Vol 383-390 ◽  
pp. 4482-4485
Author(s):  
Li Sun ◽  
Yong Chen Liu
Keyword(s):  
Time Course ◽  
Load Spectrum ◽  
Processing Load ◽  
Random Load ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Wheel Loader ◽  
Virtual Test ◽  
Low Pass ◽  
Filter Frequency

To determine fatigue life of Loader transmission and to analyze machine power for different user, the torque loads of wheel loader transmission are tested and calibrated with the method of four sections per cycle. The disturbed signals are filtered by low-passed filter, and anomalous spikes are eliminated with the NSOFT. And contrastively analyzes the disposal effect of signal, then acquires pure random load-time course. It concludes that one Hz of the low-pass filter frequency is suitable, and the test signal is in line with the actual work of Loader. These provide the base for getting load spectrum and virtual test on wheel loader transmission.

THE DIFFERENTIAL DIFFERENCE OPERATIONAL FLOATING AMPLIFIER: NEW CMOS REALIZATIONS AND APPLICATIONS

2009 ◽  
Vol 18 (07) ◽  
pp. 1287-1308 ◽  
Author(s):  
EMAN A. SOLIMAN ◽  
SOLIMAN A. MAHMOUD
Keyword(s):  
Analog Circuits ◽  
Cmos Technology ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Variable Gain Amplifiers ◽  
Variable Gain ◽  
Fully Differential ◽  
Filter Performance ◽  
Low Pass ◽  
Band Pass

This paper presents different novel CMOS realizations for the differential difference operational floating amplifier (DDOFA). The DDOFA was first introduced in Ref. 1 and was used to realize different analog circuits like integrators, filters and variable gain amplifiers. New CMOS realizations for the DDOFA are introduced in this literature. Furthermore the DDOFA is modified to realize a fully differential current conveyor (FDCC). Novel CMOS realizations of the FDCC are presented. The FDCC is used to realize second-order band pass–low-pass filter. Performance comparisons between the different realizations of the DDOFA and FDCC are given in this literature. PSPICE simulations of the overall proposed circuits are given using 0.25 μm CMOS Technology from TMSC MOSIS model and dual supply voltages of ±1.5 V.

Disturbance Elimination of Buck-Converter with Resonant LPF via ILQ Servo-System

2014 ◽  
Vol 492 ◽  
pp. 493-498
Author(s):  
Shuhei Shiina ◽  
Sidshchadhaa Aumted ◽  
Hiroshi Takami
Keyword(s):  
Transfer Functions ◽  
Design Method ◽  
Servo System ◽  
State Equation ◽  
Buck Converter ◽  
Linear Quadratic ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
The Stability

The proposed optimal control on the basis of both current and voltage of the buck-converter is designed to be based on Inverse Linear Quadratic (ILQ) design method with the resonant low pass filter, which eliminates the disturbance by appended disturbance compensator. The designed scheme is composed of the state equation, an optimal ILQ solution, the ILQ servo-system with the disturbance elimination, the optimal basic gain, the optimal condition, the transfer functions and the disturbance compensator. Our results show the proposed strategy is the stability and robust control and has been made to improve ILQ control for the disturbance elimination of the output response, which guarantees the optimal gains on the basis of polynomial pole assignment.

Design of a Sine Sweeping Constant Current Source Based FPGA and DDS

2014 ◽  
Vol 936 ◽  
pp. 2230-2234
Author(s):  
Ya Ping Yu ◽  
Hui Zhao ◽  
Yuan Liu ◽  
Ren Jie Yang ◽  
Gui Mei Dong ◽  
...  
Keyword(s):  
Frequency Control ◽  
Current Source ◽  
Sine Wave ◽  
Constant Current ◽  
Constant Current Source ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Fpga Chip ◽  
Sine Wave Generator

This paper designed a range of 0.1 ~ 250 kHz sine wave sweeping constant current source, which sine wave generator based on FPGA chip and DDS technology, the desired sine wave frequency was obtained by controlling the frequency control words. Low-pass filter circuit was realized by using the LTC1560-1, conversion circuit from the voltage to the current was consisted of a Howland current pump. The constant current source shows a good spectral impedance purity and amplitude.

The Design of Ideal Positioning Servo System

2015 ◽  
Vol 816 ◽  
pp. 132-139
Author(s):  
Ľubica Miková ◽  
Alexander Gmiterko ◽  
Michal Kelemen
Keyword(s):  
Frequency Characteristic ◽  
Pid Controller ◽  
Transfer Functions ◽  
Servo System ◽  
Second Order ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Degree Of Stability

The paper deals with the design of an ideal positioning servo system. To achieve this aim, we will derive transfer functions of the PID controller and the second-order low-pass filter while using typical fault frequencies for PID controller with a low pass filter. Consequently, an overall frequency characteristic of the open servo system will be depicted. This characteristic will be further used to determine the amplitude and phase safety, which determine the degree of stability system.

Broadband temporal stimuli decrease the integration time of neurons in cat striate cortex

1992 ◽  
Vol 9 (1) ◽  
pp. 39-45 ◽  
Author(s):  
R.C. Reid ◽  
J.D. Victor ◽  
R.M. Shapley
Keyword(s):  
Cortical Neurons ◽  
Time Course ◽  
Striate Cortex ◽  
Ganglion Cells ◽  
Temporal Frequency ◽  
Integration Time ◽  
Systematic Change ◽  
Response Dynamics ◽  
Pass Filter ◽  
Low Pass Filter

AbstractWe have studied the responses of striate cortical neurons to stimuli whose contrast is modulated in time by either a single sinusoid or by the sum of eight sinusoids. The sum-of-sinusoids stimulus resembles white noise and has been used to study the linear and nonlinear dynamics of retinal ganglion cells (Victor et al., 1977). In cortical neurons, we have found different linear and second-order responses to single-sinusoid and sum-of-sinusoids inputs. Specifically, while the responsivity near the optimal temporal frequency is lower for the sum-of-sinusoids stimulus, the responsivity at higher temporal frequencies is relatively greater. Along with this change in the response amplitudes, there is a systematic change in the time course of responses. For complex cells, the integration time, the effective delay due to a combination of actual delays and low-pass filter stages, changes from a median of 85 ms with single sinusoids to 57 ms with a sum of sinusoids. For simple cells, the integration times for single sinusoids range from 44–100 ms, but cluster tightly around 40 ms for the sum-of-sinusoids stimulus. The change in time constant would argue that the increased sensitivity to high frequencies cannot be explained by a static threshold, but must be caused by a fundamental alteration in the response dynamics. These effects are not seen in the retina (Shapley & Victor, 1981) and are most likely cortical in origin.

Band-Stop Filter Algorithm Research Based on Nano-Displacement Positioning System

2013 ◽  
Vol 380-384 ◽  
pp. 697-700 ◽  
Author(s):  
Yue Zhou ◽  
Xiao Xiao Yao ◽  
Jin Xiang Pian ◽  
Yan Qiang Su
Keyword(s):  
Transfer Functions ◽  
Experimental Simulation ◽  
Infinite Impulse Response ◽  
Positioning System ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Control Precision ◽  
Band Stop Filter ◽  
Low Pass ◽  
Inherent Frequency

This paper proposed the algorithms of infinite impulse response (IIR) band-stop filter and all-pass filter to eliminate the inherent frequency for piezoelectric ceramics and improve the control precision for nanodisplacement positioning system. The IIR algorithm was composed of five steps (such as the determination of normalized frequency, filter orders and transfer functions of analog low-pass filter, analog band-stop filter and digital band-stop filter). Based on the experimental simulation results on the nanodisplacement positioning platform, the butterworth band-stop filter algorithm can achieve the requested filtering effects within 10 orders .

scholarly journals High-Performance RF Balanced Microstrip Mixer Configuration for Cryogenic and Room Temperatures

Electronics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 102
Author(s):  
Noy Citron ◽  
Eldad Holdengreber ◽  
Oz Sorkin ◽  
Shmuel E. Schacham ◽  
Eliyahu Farber
Keyword(s):  
High Performance ◽  
Schottky Diodes ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Noise Rejection ◽  
Low Pass ◽  
Hybrid Coupler ◽  
Band Pass ◽  
Simulation Results

A high-performance S-band down-conversion microstrip mixer, for operation from 77 K to 300 K, is described. The balanced mixer combines a 90 degree hybrid coupler, two Schottky diodes, a band pass filter, and a low pass filter. The coupler phase shift drastically improves noise rejection. The circuit was implemented according to the configuration obtained from extensive simulation results based on electromagnetic analysis. The experimental results agreed well with the simulation results, showing a maximum measured insertion loss of 0.4 dB at 2 GHz. The microstrip mixer can be easily adjusted to different frequency ranges, up to about 50 GHz, through the proper choice of microstrip configuration. This novel S-band cryogenic mixer, implemented without resorting to special components, shows a very high performance at liquid nitrogen temperatures, making this mixer very suitable for high-temperature superconductive applications, such as front-ends.

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