The Brain and Regulation of Eye Movement

Shakhnovich, A. R.

doi:10.1007/978-1-4684-6964-6

Cited by 14 publications

(13 citation statements)

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“…Non-critical: If FeyeM can be centrally controlled (Shakhnovich, 1977; Coakley, 1983; Eizenman et al, 1985), subjects should modify the frequencies, amplitudes, and/or velocities of their FeyeM according to the spatial frequency content of the image.Such adaptations should occur during long fixations (>200 ms), and are expected to stabilize at conditions that produce temporal frequencies (at the retinal output) within the alpha or gamma ranges, which are probably preferred by thalamocortical loops.Opening eyes in full darkness, or against a uniform image, should not desynchronize cortical EEG. Cortical EEG is expected to desynchronize only when viewing a patterned image, in which case different cortical oscillators are expected to track different temporal patterns.…”

Section: Discussionmentioning

confidence: 99%

Seeing via Miniature Eye Movements: A Dynamic Hypothesis for Vision

Ahissar

Arieli

2012

Front. Comput. Neurosci.

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During natural viewing, the eyes are never still. Even during fixation, miniature movements of the eyes move the retinal image across tens of foveal photoreceptors. Most theories of vision implicitly assume that the visual system ignores these movements and somehow overcomes the resulting smearing. However, evidence has accumulated to indicate that fixational eye movements cannot be ignored by the visual system if fine spatial details are to be resolved. We argue that the only way the visual system can achieve its high resolution given its fixational movements is by seeing via these movements. Seeing via eye movements also eliminates the instability of the image, which would be induced by them otherwise. Here we present a hypothesis for vision, in which coarse details are spatially encoded in gaze-related coordinates, and fine spatial details are temporally encoded in relative retinal coordinates. The temporal encoding presented here achieves its highest resolution by encoding along the elongated axes of simple-cell receptive fields and not across these axes as suggested by spatial models of vision. According to our hypothesis, fine details of shape are encoded by inter-receptor temporal phases, texture by instantaneous intra-burst rates of individual receptors, and motion by inter-burst temporal frequencies. We further describe the ability of the visual system to readout the encoded information and recode it internally. We show how reading out of retinal signals can be facilitated by neuronal phase-locked loops (NPLLs), which lock to the retinal jitter; this locking enables recoding of motion information and temporal framing of shape and texture processing. A possible implementation of this locking-and-recoding process by specific thalamocortical loops is suggested. Overall it is suggested that high-acuity vision is based primarily on temporal mechanisms of the sort presented here and low-acuity vision is based primarily on spatial mechanisms.

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Section: Discussionmentioning

confidence: 99%

Seeing via Miniature Eye Movements: A Dynamic Hypothesis for Vision

Ahissar

Arieli

2012

Front. Comput. Neurosci.

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“…Binocular vision is characterized by vergence of the eyes, which is further distinguished as either fusional or accommodative. Retinal disparity, the horizontal difference of the retinal projections of a point at distance, drives fusional vergence [Shakhnovich 1977], whereas retinal blur drives accommodative vergence [Büttner-Ennever 1988]. Both types of vergence are known to be tightly coupled in the human visual system [Fincham and Walton 1957].…”

Section: Measured Error Vs Expected Errormentioning

confidence: 99%

Online 3D Gaze Localization on Stereoscopic Displays

Wang

Pelfrey

Duchowski

et al. 2014

ACM Trans. Appl. Percept.

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This article summarizes our previous work on developing an online system to allow the estimation of 3D gaze depth using eye tracking in a stereoscopic environment. We report on recent extensions allowing us to report the full 3D gaze position. Our system employs a 3D calibration process that determines the parameters of a mapping from a naive depth estimate, based simply on triangulation, to a refined 3D gaze point estimate tuned to a particular user. We show that our system is an improvement on the geometry-based 3D gaze estimation returned by a proprietary algorithm provided with our tracker. We also compare our approach with that of the Parameterized Self-Organizing Map (PSOM) method, due to Essig and colleagues, which also individually calibrates to each user. We argue that our method is superior in speed and ease of calibration, is easier to implement, and does not require an iterative solver to produce a gaze position, thus guaranteeing computation at the rate of tracker acquisition. In addition, we report on a user study that indicates that, compared with PSOM, our method more accurately estimates gaze depth, and is nearly as accurate in estimating horizontal and vertical position. Results are verified on two different 4D eye tracking systems, a high accuracy Wheatstone haploscope and a medium accuracy active stereo display. Thus, it is the recommended method for applications that primarily require gaze depth information, while its ease of use makes it suitable for many applications requiring full 3D gaze position.

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“…By its physical characteristics, the molten globule contains the properties of both native and unfolded states. The decrease of specific interactions, as well as unfreezing of structure fluctuations are used as the explanation for the existence of the intermediate state, which is in accordance with the theory of conformational transitions [13].…”

Section: Resultsmentioning

confidence: 60%

Similarity of protein conformation at low pH and high temperature observed for B‐chains of two plant toxins: ricin and mistletoe lectin 1

Bushueva

Tonevitsky

1988

FEBS Letters

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A comparative study of subunits of two plant toxins, ricin (RC) and mistletoe lectin 1 (ML 1), has been undertaken. The study suggests that isolated B-chains of these toxins undergo structural transitions at low pH (from 5 to 4) and high temperature (45°C), and as a result of the guanidine hydrochloride denaturing effect (to 3 M). Our results indicate that the protein conformation observed at low pH and high temperature are similar, though not identical. These conformations differ from the native one (pH 7, 25°C), the protein in these conformations has a low fluorescence tryptophan intensity, and tryptophans are more exposed to aqueous solutions. However, these conformations differ also from the state unfolded by guanidine hydrochioride. An assumption is made that the partially denatured protein structure, exhibited at low pH and high temperature, is a functionally essential intermediate state of the toxin B-chain.Ricin B-chain; Lectin B-chain; Protein fluorescence; (Mistletoe)

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The Brain and Regulation of Eye Movement

Cited by 14 publications

References 0 publications

Seeing via Miniature Eye Movements: A Dynamic Hypothesis for Vision

Seeing via Miniature Eye Movements: A Dynamic Hypothesis for Vision

Online 3D Gaze Localization on Stereoscopic Displays

Similarity of protein conformation at low pH and high temperature observed for B‐chains of two plant toxins: ricin and mistletoe lectin 1

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