The use of m-sequences in the analysis of visual neurons: Linear receptive field properties

Reid, R. Clay; Victor, Jonathan D.; Shapley, Robert

doi:10.1017/s0952523800011743

Cited by 215 publications

(240 citation statements)

References 47 publications

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“…For example, when cat LGN cells were studied with drifting sinusoidal gratings, a somewhat lower precision was found in responses to high-contrast gratings ( ϭ 5 msec), and substantially less precision was seen in responses to moderate contrast gratings (Reich et al, 1997). We also observed lower precision in the responses to checkerboard M-sequence stimuli (Reid et al, 1997) (ϳ10 msec, our unpublished observation). The white-noise stimulus used here had moderate contrast (Fig.…”

Section: Temporal Precision Of Firingmentioning

confidence: 60%

Temporal Coding of Visual Information in the Thalamus

2000

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The amount of information a sensory neuron carries about a stimulus is directly related to response reliability. We recorded from individual neurons in the cat lateral geniculate nucleus (LGN) while presenting randomly modulated visual stimuli. The responses to repeated stimuli were reproducible, whereas the responses evoked by nonrepeated stimuli drawn from the same ensemble were variable. Stimulus-dependent information was quantified directly from the difference in entropy of these neural responses. We show that a single LGN cell can encode much more visual information than had been demonstrated previously, ranging from 15 to 102 bits/sec across our sample of cells. Information rate was correlated with the firing rate of the cell, for a consistent rate of 3.6 Ϯ 0.6 bits/spike (mean Ϯ SD). This information can primarily be attributed to the high temporal precision with which firing probability is modulated; many individual spikes were timed with better than 1 msec precision. We introduce a way to estimate the amount of information encoded in temporal patterns of firing, as distinct from the information in the time varying firing rate at any temporal resolution. Using this method, we find that temporal patterns sometimes introduce redundancy but often encode visual information. The contribution of temporal patterns ranged from Ϫ3.4 to ϩ25.5 bits/sec or from Ϫ9.4 to ϩ24.9% of the total information content of the responses.Key words:LGN; neural coding; information theory; entropy; white noise; reliability; variability Cells in the lateral geniculate nucleus of the thalamus (LGN) respond to spatial and temporal changes in light intensity within their receptive fields. The collective responses of many such cells constitute the input to visual cortex. All stimulus discrimination at the perceptual level must ultimately be supported by reliable differences in the neural response at the level of the LGN cell population. We are therefore interested in measuring the statistical discriminability of LGN responses elicited by different visual stimuli.It has been shown that the LGN can respond to visual stimuli with remarkable temporal precision (Reich et al., 1997). This implies that LGN neurons have the capability to signal information at high rates. Previous estimates of the information in LGN responses have used two general approaches. The first approach, stimulus reconstruction, relies on an explicit model of what the neuron is encoding, as well as an algorithm for decoding it (Bialek et al., 1991;Rieke et al., 1997). This method has been used to place lower bounds on the information encoded by single neurons (Reinagel et al., 1999) or pairs of neurons (Dan et al., 1998) in the LGN in response to dynamic visual stimuli.The second approach, the "direct" method, relies instead on statistical properties of the responses to different stimuli (the entropy of the responses). Because this involves only comparisons of spike trains, without reference to stimulus parameters, we need not know what features of the stimulus the cell ...

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Section: Temporal Precision Of Firingmentioning

confidence: 60%

Temporal Coding of Visual Information in the Thalamus

2000

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“…On a daily basis, we placed a microwire bundle electrode, or tetrode (15), in the LGN and mapped the visual responses (RFs) of cells for a given location of the electrode (16). We then used a center-out saccade task where the animal was required to sit in front of a computer screen and was rewarded for making saccadic eye movements from a central fixation point of light to a target point a short distance away.…”

Section: Resultsmentioning

confidence: 99%

Demonstration of artificial visual percepts generated through thalamic microstimulation

Pezaris

Reid²

2007

Proc. Natl. Acad. Sci. U.S.A.

163

133

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Electrical stimulation of the visual system might serve as the foundation for a prosthetic device for the blind. We examined whether microstimulation of the dorsal lateral geniculate nucleus of the thalamus can generate localized visual percepts in alert monkeys. To assess electrically generated percepts, an eyemovement task was used with targets presented on a computer screen (optically) or through microstimulation of the lateral geniculate nucleus (electrically). Saccades (fast, direct eye movements) made to electrical targets were comparable to saccades made to optical targets. Gaze locations for electrical targets were well predicted by measured visual response maps of cells at the electrode tips. With two electrodes, two distinct targets could be independently created. A sequential saccade task verified that electrical targets were processed not in motor coordinates, but in visual spatial coordinates. Microstimulation produced predictable visual percepts, showing that this technique may be useful for a visual prosthesis.primate ͉ prosthesis ͉ tetrode

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“…In fact, the modulation transfer function is probably the most common measure of how faithfully a lens, a human observer or a visual neuron reproduces the spatial frequency of a grating (27)(28)(29). Binary stimuli (light and dark luminance values) are also widely used to estimate spatiotemporal receptive fields (30)(31)(32)(33). However, both modulation transfer functions and linear receptive field estimates assume that darks and lights drive neuronal responses with equal strength and neuronal populations with similar spatial resolution, two assumptions that are not supported by our results.…”

Section: Discussionmentioning

confidence: 99%

Neuronal nonlinearity explains greater visual spatial resolution for darks than lights

Kremkow

Jin

Komban

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

127

229

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Astronomers and physicists noticed centuries ago that visual spatial resolution is higher for dark than light stimuli, but the neuronal mechanisms for this perceptual asymmetry remain unknown. Here we demonstrate that the asymmetry is caused by a neuronal nonlinearity in the early visual pathway. We show that neurons driven by darks (OFF neurons) increase their responses roughly linearly with luminance decrements, independent of the background luminance. However, neurons driven by lights (ON neurons) saturate their responses with small increases in luminance and need bright backgrounds to approach the linearity of OFF neurons. We show that, as a consequence of this difference in linearity, receptive fields are larger in ON than OFF thalamic neurons, and cortical neurons are more strongly driven by darks than lights at low spatial frequencies. This ON/OFF asymmetry in linearity could be demonstrated in the visual cortex of cats, monkeys, and humans and in the cat visual thalamus. Furthermore, in the cat visual thalamus, we show that the neuronal nonlinearity is present at the ON receptive field center of ONcenter neurons and ON receptive field surround of OFF-center neurons, suggesting an origin at the level of the photoreceptor. These results demonstrate a fundamental difference in visual processing between ON and OFF channels and reveal a competitive advantage for OFF neurons over ON neurons at low spatial frequencies, which could be important during cortical development when retinal images are blurred by immature optics in infant eyes.neuronal coding | lateral geniculate nucleus | area V1 | irradiation illusion | LFP L ight and dark stimuli are separately processed by ON and OFF channels in the retina and visual thalamus. Surprisingly, although most textbooks assume that ON and OFF visual responses are balanced throughout the visual system, recent studies have identified a pronounced overrepresentation of the OFF visual responses in primary visual cortex (area V1) (1-3). This recent discovery resonates with pioneering studies by Galilei (4) and von Helmholtz (5) who noticed that visual spatial resolution was higher for dark than light stimuli. Galilei (4) related the difference in resolution to the observation that a light patch on a dark background appears larger than the same sized dark patch on a light background, an illusion that von Helmholtz (5) named the "irradiation illusion." Although this illusion has been studied in the past (6, 7), its underlying neuronal mechanisms remain unknown. It has been suggested that the perceived size differences could be caused by the light scatter in the optics of the eye followed by a neuronal nonlinearity (6, 7), but there are no neuronal measurements of a nonlinearity that fits the explanation. Previous studies revealed differences in response linearity between ON and OFF retinal ganglion cells (8, 9) and horizontal cells (10). However, a main conclusion from these studies was that ON retinal ganglion cells were roughly linear and less rectified than OFF retinal gangl...

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The use of m-sequences in the analysis of visual neurons: Linear receptive field properties

Cited by 215 publications

References 47 publications

Temporal Coding of Visual Information in the Thalamus

Temporal Coding of Visual Information in the Thalamus

Demonstration of artificial visual percepts generated through thalamic microstimulation

Neuronal nonlinearity explains greater visual spatial resolution for darks than lights

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