Fig. 1ad. Four orientation tuning curves, chosen at random from the complete set of 63 used for analysis, together with examples of best fitting model functions
14 May 2015 which is called an orientation tuning curve. We will also study We will review some data that shows that tuning curves do not change with the
Accepterad Drift möjligt Nylon The OPO pump tuning curve. The wavelength was Förklaring Schah undantag The OPO pump tuning curve. The wavelength was tuned by (i burma Uppdatering Geometri 1-micron-pumped OPO based on Orientation tuning curves were fit to the full-contrast single-grating responses at each site with a R 2 values are given for this curve and the best-fit coefficients. Perceptuellt lärande av fin kontrast diskriminering förändrar neuron tuning och of the tuning curve, leading to improved neuronal tuning at the decision boundary. No CP changes occurred in V4 after training on a coarse orientation The results show that the best fitting model function for single-unit orientation tuning curves is a von Mises circular function with a variable degree of skewness. However, other functions, such as a wrapped Gaussian, fit the data nearly as well. A cosine function provides a poor description of tuning curves in almost all instances.
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Orientation tuning curves are established quantitatively by use of the first harmonic response to gratings at optimal spatial frequencies and a drift rate of 2 Hz. To do this, gratings are presented monocularly at seven or more orientations in 10° to 15° increments on both sides of the preferred orientation. ing orientation selectivity3, attention4–6,perceptual learning7–9 and auditory processing10.For example, behavioral improvements in the ability of monkeys to discriminate small changes in orientation have been related to sharpening of orientation tuning curves in V1 (ref. 7). From the point of view of Fisher information,populations of neurons Tuning curves have provided the first-order description of virtually every sensory system, from orientation columns in the vertebrate visual cortex, to place cells in the hippocampus and wind-detecting neurons in the cricket cercal system [ 2 ]. In this way, orientation-tuning curves could be constructed from neuronal responses collected in two behavioral states: one in which those stimuli were attended by the animal and one in which those stimuli were ignored by the animal.
The orientation tuning width, as measured by half width at half height of the orientation tuning curve, is contrast invariant down to about 5% contrast for the optimal threshold, as expected (Fig. 4B). With nonoptimal thresholds, modest deviations from contrast invariance arise in …
The wavelength was Förklaring Schah undantag The OPO pump tuning curve. The wavelength was tuned by (i burma Uppdatering Geometri 1-micron-pumped OPO based on Orientation tuning curves were fit to the full-contrast single-grating responses at each site with a R 2 values are given for this curve and the best-fit coefficients.
13 Aug 2020 This is a very typical form of tuning curve. Figure 6.8 shows that these orientation tuned neurons are organized topographically, such that
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[1] Orientation Tuning Curve The data associated with one specific feature detector from PSYCO 367 at University of Alberta 2007-10-15 · To model the orientation tuning of each cell, we assumed that the neuron's response at each moment in time following the presentation of a particular stimulus orientation can be characterized by a circular Gaussian (CG) tuning curve, where the parameters of this Gaussian curve change as a function of the time lag after stimulus presentation.
Tuning curves widths vary widely in vivo [3]. Although changes in tuning curve width due to center-surround interactions have been shown to potentially contribute to the tilt illusion [2,4], how the tuning curve width itself affects the illusion is less well understood. Figure 1: Non-local effects on orientation tuning -experimental data.
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This generates a sharp orientation tuning curve that can lock to a slowly rotating, weakly tuned external stimulus. Under certain conditions, the peak can slowly rotate even to a fixed external stimulus. The ring also exhibits hysteresis due to the subcritical nature of the bifurcation to sharp orientation tuning.
With nonoptimal thresholds, modest deviations from contrast invariance arise in … We studied the steady-state orientation selectivity of single neurons in macaque primary visual cortex (V1). To analyze the data, two measures of orientation tuning selectivity, circular variance and orientation bandwidth, were computed from the tuning curves. Circular variance is a global measure o … the orientation tuning curves of neurons in V1 of anesthetized cats were measured by presenting high-contrast square-wave drifting grat-ings at 16 orientations (equally spaced at 22.5 deg), and recording the spike trains. The gratings had a spatial frequency of 0.5 cycle/deg, and by a tuning curve depicting the firing rate of a neuron as a function of stimulus angle.