scholarly journals White noise analysis of a chromatic type horizontal cell in the Xenopus retina.

1994 ◽  
Vol 103 (6) ◽  
pp. 991-1017 ◽  
Author(s):  
S L Stone
Keyword(s):  
White Noise ◽  
Blue Light ◽  
Noise Analysis ◽  
Horizontal Cell ◽  
Red Light ◽  
Cutoff Frequency ◽  
Horizontal Cells ◽  
Nonlinear Phenomena ◽  
Experimental Conditions ◽  
First Order

The dynamics of color-coded signal transmission in the light-adapted Xenopus retina were studied by a combination of white noise (Wiener) analysis and simultaneous recordings from two types of horizontal cells: chromatic-type horizontal cells (C-HCs) are hyperpolarized by blue light and depolarized by red light, whereas luminosity-type horizontal cells (L-HCs) are hyperpolarized by all wave-lengths. The retina was stimulated by two superimposed fields of red and blue light modulated by two independent white noise signals, and the resulting intracellular responses were decomposed into red and blue components (first-order kernels). The first-order kernels predict the intracellular responses with a small degree of error (3.5-9.5% in terms of mean square error) under conditions where modulated responses exceeded 30 mV in amplitude peak-to-peak, thus demonstrating that both red and blue modulation responses are linear. Moreover, there is little or no interaction between the red- and blue-evoked responses; i.e., nearly identical first-order kernels were obtained for one color whether the other color was modulated or not. In C-HCs (but not L-HCs), there were consistent differences in the dynamics of the red and blue responses. In the C-HC, the cutoff frequency of the red response was higher than for the blue (approximately 12 vs 5 Hz), and the red kernel was more bandpass than the blue. In the L-HC, kernel waveform and cutoff frequencies were similar for both colors (approximately 12 Hz or greater), and the time-to-peak of the L-HC kernel was always shorter than either the red or blue C-HC kernel. These results have implications for the mechanisms underlying color coding in the distal retina, and they further suggest that nonlinear phenomena, such as voltage-dependent conductances in HCs, do not contribute to the generation of modulation responses under the experimental conditions used here.

Processing of Color- and Noncolor-Coded Signals in the Gourami Retina. I. Horizontal Cells

1997 ◽  
Vol 78 (4) ◽  
pp. 2002-2017 ◽  
Author(s):  
Hiroko M. Sakai ◽  
Hildred Machuca ◽  
Ken-Ichi Naka
Keyword(s):  
White Noise ◽  
Horizontal Cell ◽  
Green Light ◽  
Noise Signal ◽  
Horizontal Cells ◽  
Response Dynamics ◽  
Modulation Response ◽  
First Order ◽  
Average Mean Square Error ◽  
Hyperpolarizing Response

Sakai, Hiroko M., Hildred Machuca, and Ken-Ichi Naka. Processing of color- and noncolor-coded signals in the gourami retina. I. Horizontal cells. J. Neurophysiol. 78: 2002–2017, 1997. There are two types of horizontal cells, the luminosity and the chromaticity cells, in the retina of the kissing gourami, Helostoma rudolfi. Luminosity cells occupy the outermost layer proximal to the receptor terminals, whereas chromaticity cells form a layer proximal to the layer of luminosity cells. Neither type of cell has axons. Responses were evoked by light from red and green light-emitting diodes. The two stimuli were modulated either by a pulsatile or a white-noise signal. The luminosity cell always produced a hyperpolarizing response. The chromaticity cell produced a hyperpolarizing response when stimulated by only one color. However, in the presence of a steady or modulated green input, a red stimulus produced a depolarizing response. Such chromaticity cells were similar to the (spectral) biphasic chromaticity horizontal cells observed in other retinae. The depolarizing phase of the red response was produced by the balance of intensity of the two inputs, red and green. We used white-noise methodology to identify the dynamics of the horizontal cell's modulation response by taking advantage of the fact that a Wiener kernel is a measure of a cell's incremental sensitivity, which includes its response dynamics. Under all conditions, a steady state modulation response by both luminosity and chromaticity cells always was related linearly to the input modulation. The average mean square error (MSE) of the model predicted by the first-order kernel was ∼8% for both luminosity ( n = 116) and chromaticity ( n = 23) cells. In some cases, the MSE was a few percent even when the peak-to-peak response amplitude was nearly 30 mV. The ratio of inputs from red and green cones to both types of horizontal cells was variable; the major input for luminosity cells came from red cones, whereas the major input for chromaticity cells came from green cones. First-order kernels generated by the major input were robust in terms of waveform in the sense that the waveform remained unchanged whether or not there was a steady or modulated illumination by the opposing color. The results reported here do not address the question of the neural circuitry that generates horizontal cell responses, in particular, the depolarizing response. However, whatever that circuitry might be, the high degree of linearity of the modulation response by both types of cell under various stimulus conditions imposes restrictions on the performance of any proposed model as well as on mechanisms that underlie the generation of the horizontal cell response.

On the Nature of the Gated Colour Opponency in the On-Units of the Frog Retina: Electrophysiological Study and Model

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 262-262 ◽  
Author(s):  
E M Maximova ◽  
V V Maximov ◽  
O Y Orlov
Keyword(s):  
Blue Light ◽  
Single Unit ◽  
Ganglion Cells ◽  
Electrophysiological Study ◽  
Red Light ◽  
Horizontal Cells ◽  
Unit Recording ◽  
Cell Responses ◽  
Blue Channel ◽  
Frog Retina

Ganglion cells of the ON-type in the frog retina produce colour-dependent responses differing in temporal patterns (short bursts to excitation of red-sensitive cones as opposed to prolonged discharges if blue-sensitive ‘green rods’ are excited). Their gated colour opponency (Kicliter et al, 1981 Brain Research210 103 – 113; Maximov et al, 1985 Vision Research25 1037 – 1049) becomes apparent from the OFF-responses in conditions when the test stimuli are superimposed on a background of another colour. So, when blue glass is introduced in the light beam (decreasing the excitation mainly of red-sensitive cones), an OFF-response is observed, much like the response to the onset of blue light. It has been suggested that opponency in ON-cells is asymmetric, ie that the red signal reaches the blue channel with reversed sign, but not vice versa. A single-unit-recording study revealed the dependence of ON-cell responses both on the colour of stimuli presented in the centre of the receptive field and on the steady illumination of its surround. Surround illumination was found to favour OFF-responses in ON-units. In some cases even the cessation of blue light elicited an OFF-response with a discharge pattern resembling that of the onset of red light. In these cases an ON-response to yellow glass could also be obtained. These observations prove some degree of symmetry in the opponency of the red and blue channels. It is suggested that feedback from horizontal cells onto photoreceptor terminals is involved in the gated colour opponency. A circuit model that reproduces the observed phenomena is presented.

Adaptation in catfish retina

1979 ◽  
Vol 42 (2) ◽  
pp. 441-454 ◽  
Author(s):  
K. I. Naka ◽  
R. Y. Chan ◽  
S. Yasui
Keyword(s):  
Time Course ◽  
Ganglion Cells ◽  
Receptor Cell ◽  
Signal Transmission ◽  
Horizontal Cell ◽  
Horizontal Cells ◽  
Intensity Curve ◽  
Absolute Sensitivity ◽  
First Order ◽  
Intensity Axis

1. We define absolute sensitivity as (voltage/illuminance) and incremental sensitivity as the peak-to-peak amplitude of the first-order (Wiener) kernels. 2. Incremental sensitivity of the horizontal cells is the local slopes of the Michaelis-Menten equation and that of more proximal neurons is the Fechner slope. In a log-log plot, the former has a slope of -2, whereas the latter a slope of -1, as predicted by Williams and Gale (39). 3. During a moderate to strong steady illumination, absolute sensitivity decreases but incremental sensitivity increases. The reverse occurs during dark adaptation. 4. The presence of a steady illumination did not prevent signal transmission from horizontal to ganglion cells. 5. From these results we conclude that: adaptation in the catfish retina includes two components: a) a lateral shift of the voltage-intensity curve along the intensity axis, and b) changes in the time course of light-evoked response. We argue that the latter phenomenon is related to the presumed horizontal cell-to-receptor cell negative feedback.

Response of carp (Cyprinus carpio) horizontal cells to heterochromatic flicker photometry

2006 ◽  
Vol 23 (3-4) ◽  
pp. 437-440 ◽  
Author(s):  
MARLISON JOSÉ L. DE AGUIAR ◽  
DORA FIX VENTURA ◽  
MANOEL DA SILVA FILHO ◽  
JOHN MANUEL DE SOUZA ◽  
ROGÉRIO MACIEL ◽  
...  
Keyword(s):  
Horizontal Cell ◽  
Red Light ◽  
Green Light ◽  
Physiological Solution ◽  
Horizontal Cells ◽  
Xenon Lamp ◽  
Constant Amplitude ◽  
Light Levels ◽  
Electrophysiological Recordings ◽  
Heterochromatic Flicker Photometry

The objective of the present work was to determine the interaction of cone inputs in the response of horizontal cells using heterochromatic flicker photometry (HFP). Intracellular electrophysiological recordings were made in horizontal cells of isolated retinae of carp maintained in physiological solution, with the receptor side up. Sharp glass microelectrodes filled with 3 M KCl solution with resistances between 100 and 120 MΩ were used. Stimuli comprised six cycles of two 6-Hz sinusoidal light waves in counterphase adjusted for the same number of quanta: a green light (550 nm) from a monochromator with a Xenon lamp and an LED red light (628 nm). The stimulation program consisted of 10 steps with the 550-nm wave at constant amplitude, while the 628-nm wave varied in increments of 10% up to 100%, followed by another 10 steps with the 628-nm wave at constant amplitude while the 550-nm wave varied in increments of 10% up to 100%. We recorded responses from four different horizontal cell classes: H1 (monophasic, broadband, n = 37), H2 (biphasic, red-green color-opponent, n = 13), and H3 (biphasic, blue-yellow color-opponent, n = 2) cone horizontal cells; and RH (monophasic, broadband, n = 3) rod horizontal cells. H1 and RH horizontal cells showed a similar cancellation point at a heterochromatic mixture consistent with mixed inputs from 630- and 550-nm cones. No cancellation point was found for the H2 cell class. Fish H1 cells add cone inputs and signal “luminance” in light levels appropriate for cone stimulation. The same occurs with RH cells, which also signal “luminance,” but in light levels appropriate for rod work. For both cell classes there is an HFP cancellation point occurring at a combination of 628-nm and 550-nm lights in opposing phase that leads to the cancellation of the cell's response. No cancellation was found for H2 and H3 cells, which are the chromatically opponent horizontal cells in lower vertebrates.

Physiological and pharmacological analysis of suppressive rod-cone interaction in Necturus retina [corrected]

1989 ◽  
Vol 61 (4) ◽  
pp. 866-877 ◽  
Author(s):  
T. Eysteinsson ◽  
T. E. Frumkes
Keyword(s):  
Light Adaptation ◽  
Horizontal Cell ◽  
Red Light ◽  
Background Field ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Lead Chloride ◽  
Inhibitory Influence ◽  
Third Order ◽  
Small Spot

1. Intracellular recordings were obtained from retinal neurons of the mudpuppy, Necturus, while superfusing the eyecup with various pharmacologic agents. In most experiments, the retina was continuously stimulated with a small spot of red light that was centered over the recording electrode and flickering at rates too fast for amphibian rods to follow. The retina was additionally stimulated intermittently with a dim, spatially diffuse background field of 520 nm wavelength. 2. In general, the dim background greatly enhanced flicker responsiveness. We (16) previously called this effect suppressive rod-cone interaction (SRCI) and showed it reflects a tonic suppressive influence on cone pathways that is removed by selective rod-light adaptation. 3. Lead chloride has been claimed to selectively block rod-related retinal responses (13, 35). While recording from horizontal cells lead chloride decreases responses to the dim, diffuse light flashes, enhances the frequency entrained response attributable to cones, and eliminates a background influence on flicker responses. 4. O-phospho-D-serine (DOP), kynurenic acid (KyA), and piperidine dicarboxylic acid are known to act on horizontal cells as antagonists of the photoreceptor neurotransmitter (26, 32, 33). In both depolarizing and hyperpolarizing bipolar cells, these agents enhance flicker responsiveness with no background present and prevent background enhancement of flicker. 5. Mudpuppy cones were found to have a receptive-field surround, which under our stimulus conditions is attributable to rod input. KyA, which is unknown to have any direct influence on photoreceptors, totally blocks this surround mechanism. This indicates that the cone-surround mechanism is attributable to horizontal cell feedback. The influence of KyA on SRCI in cones is similar to that observed in recordings from depolarizing bipolar cells. 6. Most sustained third-order neurons demonstrate SRCI. In these cells, SRCI is blocked by DOP or KyA. Most ON-OFF neurons fail to demonstrate SRCI under control circumstances. The ON-response of these cells is blocked by 2-amino-4-phosphonobutyric acid (31) which leaves the OFF-response intact. While their ON-response is blocked, ON-OFF neurons demonstrate SRCI. 7. The foregoing results indicate that SRCI reflects a tonic, inhibitory influence of horizontal cells on cone pathways that is removed by light-adapting rods. In part, SRCI must involve horizontal cell feedback onto cones. SRCI in third-order neurons appears to largely reflect distal retinal processing.

Dynamics of Neurons Controlling Movements of a Locust Hind Leg III. Extensor Tibiae Motor Neurons

1997 ◽  
Vol 77 (6) ◽  
pp. 3297-3310 ◽  
Author(s):  
Philip L. Newland ◽  
Yasuhiro Kondoh
Keyword(s):  
White Noise ◽  
Motor Neurons ◽  
Cutoff Frequency ◽  
Second Order ◽  
Chordotonal Organ ◽  
Inhibitory Input ◽  
Pass Filter ◽  
Low Pass Filter ◽  
First Order ◽  
Synaptic Responses

Newland, Philip L. and Yasuhiro Kondoh. Dynamics of neurons controlling movements of a locust hind leg. III. Extensor tibiae motor neurons. J. Neurophysiol. 77: 3297–3310, 1997. Imposed movements of the apodeme of the femoral chordotonal organ (FeCO) of the locust hind leg elicit resistance reflexes in extensor and flexor tibiae motor neurons. The synaptic responses of the fast and slow extensor tibiae motor neurons (FETi and SETi, respectively) and the spike responses of SETi were analyzed with the use of the Wiener kernel white noise method to determine their response properties. The first-order Wiener kernels computed from soma recordings were essentially monophasic, or low passed, indicating that the motor neurons were primarily sensitive to the position of the tibia about the femorotibial joint. The responses of both extensor motor neurons had large nonlinear components. The second-order kernels of the synaptic responses of FETi and SETi had large on-diagonal peaks with two small off-diagonal valleys. That of SETi had an additional elongated valley on the diagonal, which was accompanied by two off-diagonal depolarizing peaks at a cutoff frequency of 58 Hz. These second-order components represent a half-wave rectification of the position-sensitive depolarizing response in FETi and SETi, and a delayed inhibitory input to SETi, indicating that both motor neurons were directionally sensitive. Model predictions of the responses of the motor neurons showed that the first-order (linear) characterization poorly predicted the actual responses of FETi and SETi to FeCO stimulation, whereas the addition of the second-order (nonlinear) term markedly improved the performance of the model. Simultaneous recordings from the soma and a neuropilar process of FETi showed that its synaptic responses to FeCO stimulation were phase delayed by about −30° at 20 Hz, and reduced in amplitude by 30–40% when recorded in the soma. Similar configurations of the first and second-order kernels indicated that the primary process of FETi acted as a low-pass filter. Cross-correlation between a white noise stimulus and a unitized spike discharge of SETi again produced well-defined first- and second-order kernels that showed that the SETi spike response was also dependent on positional inputs. An elongated negative valley on the diagonal, characteristic of the second-order kernel of the synaptic response in SETi, was absent in the kernel from the spike component, suggesting that information is lost in the spike production process. The functional significance of these results is discussed in relation to the behavior of the locust.

Nonspiking and Spiking Proprioceptors in the Crab: White Noise Analysis of Spiking CB-Chordotonal Organ Afferents

2003 ◽  
Vol 89 (4) ◽  
pp. 1815-1825 ◽  
Author(s):  
E. Rolland Gamble ◽  
Ralph A. DiCaprio
Keyword(s):  
White Noise ◽  
Information Transfer ◽  
Noise Analysis ◽  
Second Order ◽  
Chordotonal Organ ◽  
White Noise Analysis ◽  
Response Component ◽  
First Order ◽  
Wiener Kernels ◽  
Order Kernel

The proprioceptors that signal the position and movement of the first two joints of crustacean legs provide an excellent system for comparison of spiking and nonspiking (graded) information transfer and processing in a simple motor system. The position, velocity, and acceleration of the first two joints of the crab leg are monitored by both nonspiking and spiking proprioceptors. The nonspiking thoracic-coxal muscle receptor organ (TCMRO) spans the TC joint, while the coxo-basal (CB) joint is monitored by the spiking CB chordotonal organ (CBCTO) and by nonspiking afferents arising from levator and depressor elastic strands. The response characteristics and nonlinear models of the input-output relationship for CB chordotonal afferents were determined using white noise analysis (Wiener kernel) methods. The first- and second-order Wiener kernels for each of the four response classes of CB chordotonal afferents (position, position-velocity, velocity, and acceleration) were calculated and the gain function for each receptor determined by taking the Fourier transform of the first-order kernel. In all cases, there was a good correspondence between the response of an afferent to deterministic stimulation (trapezoidal movement) and the best-fitting linear transfer function calculated from the first-order kernel. All afferents also had a nonlinear response component and second-order Wiener kernels were calculated for afferents of each response type. Models of afferent responses based on the first- and second-order kernels were able to predict the response of the afferents with an average accuracy of 86%.

Dynamics of neurons controlling movements of a locust hind leg: Wiener kernel analysis of the responses of proprioceptive afferents

1995 ◽  
Vol 73 (5) ◽  
pp. 1829-1842 ◽  
Author(s):  
Y. Kondoh ◽  
J. Okuma ◽  
P. L. Newland
Keyword(s):  
White Noise ◽  
Sensory Neurons ◽  
Cutoff Frequency ◽  
Stimulus Frequency ◽  
Noise Stimulus ◽  
High Frequencies ◽  
Response Properties ◽  
First Order ◽  
Wiener Kernel ◽  
Position Sensitive

1. The response properties of proprioceptive sensory neurons providing input to the local circuits controlling leg movements of the locust have been analysed by the Wiener kernel method. The proprioceptor, the femoral chordotonal organ, encodes the position and movements of the tibia about the femorotibial joint. 2. Intracellular recordings were made from sensory neurons while the apodeme of the organ was moved with a band-limited Gaussian white noise signal with a cutoff frequency of 27, 58, or 117 Hz. To define the input-output characteristics of the neurons, the first- and second-order Wiener kernels were computed by a cross-correlation between the spike response of the afferents and the white noise stimulus. 3. White noise stimulation elicited sustained spiking in 50 out of 54 afferents throughout the 20 s periods of stimulation and recording. The first-order kernels, the linear response properties, of these afferents were of six basic types that were dependent on the cutoff frequency of the white noise stimulus. These included 1) flexion-sensitive afferents that were primarily position sensitive irrespective of stimulus frequency, 2) flexion-sensitive afferents that were position sensitive at low frequencies but also coded velocity at higher frequencies, 3) flexion-sensitive afferents that coded velocity at all stimulus frequencies, 4) flexion-sensitive afferents that coded velocity at low stimulus frequencies but also acceleration at high frequencies, 5) extension-sensitive afferents that coded velocity at all stimulus frequencies, and 6) extension-sensitive afferents that coded velocity at low stimulus frequencies and acceleration at high frequencies. A seventh type contained the four remaining afferents that adapted rapidly to the stimulus within 3-5 s. These were all extension-acceleration sensitive irrespective of stimulus frequency. 4. The gain curves (produced by Fourier transform of the 1st-order kernels) and the power spectra of the linear models (produced by convolving the 1st-order kernels with the white noise) demonstrated that responses in the position-sensitive afferents are representative of a constant gain low-pass filter with a cutoff frequency of approximately 80 Hz, whereas those in the velocity- and acceleration-sensitive afferents are band passed, having peaks at 80 Hz. 5. The main nonlinearity was a signal compression in which the diagonal peak(s) of the second-order nonlinear kernels offset one or more peaks of the first-order kernels and represents a rectification or directional sensitivity of the afferents.(ABSTRACT TRUNCATED AT 400 WORDS)

Antithrombin-mediated Inhibition of Factor Vlla-Tissue Factor Complex by the Synthetic Pentasaccharide Representing the Heparin Binding Site to Antithrombin

1996 ◽  
Vol 76 (01) ◽  
pp. 005-008 ◽  
Author(s):  
Jean Claude Lormeau ◽  
Jean Pascal Herault ◽  
Jean Marc Herbert
Keyword(s):  
Binding Site ◽  
Tissue Factor ◽  
Residual Activity ◽  
Coagulation Factors ◽  
Heparin Binding ◽  
Experimental Conditions ◽  
First Order ◽  
Heparin Binding Site ◽  
Coagulant Activity

SummaryWe examined the effect of the synthetic pentasaccharide representing the minimal binding site of heparin to antithrombin on the antithrombin-mediated inactivation of factor Vila bound to tissue factor. This effect was compared to the effect of unfractionated heparin. Using purified recombinant human coagulation factors and either a clotting or an amidolytic assay for the determination of the residual activity of factor Vila, we showed that the pentasaccharide was an efficient antithrombin-dependent inhibitor of the coagulant activity of tissue factor-factor Vila complex. In our experimental conditions, assuming a mean MW of 14,000 for heparin, the molar pseudo-first order rate constants for ATIII-mediated FVIIa inhibition by ATIII-binding heparin and by the synthetic pentasaccharide were found to be similar with respective values of 104,000 ± 10,500 min-1 and 112,000 ± 12,000 min-1 (mean ± s.e.m., n = 3)

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