ORCID Profile
0000-0003-1083-6103
Current Organisation
Rutgers University
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Publisher: Cold Spring Harbor Laboratory
Date: 15-10-2018
DOI: 10.1101/443507
Abstract: Humans and other primates rely on eye movements to explore visual scenes and to track moving objects. As a result, the image that is projected onto the retina – and propagated throughout the visual cortical hierarchy – is almost constantly changing and makes little sense without taking into account the momentary direction of gaze. How is this achieved in the visual system? Here we show that in primary visual cortex (V1), the earliest stage of cortical vision, neural representations carry an embedded “eye tracker” that signals the direction of gaze associated with each image. Using chronically implanted multi-electrode arrays, we recorded the activity of neurons in V1 during tasks requiring fast (exploratory) and slow (pursuit) eye movements. Neurons were stimulated with flickering, full-field luminance noise at all times. As in previous studies 1-4 , we observed neurons that were sensitive to gaze direction during fixation, despite comparable stimulation of their receptive fields. We trained a decoder to translate neural activity into metric estimates of (stationary) gaze direction. This decoded signal not only tracked the eye accurately during fixation, but also during fast and slow eye movements, even though the decoder had not been exposed to data from these behavioural states. Moreover, this signal lagged the real eye by approximately the time it took for new visual information to travel from the retina to cortex. Using simulations, we show that this V1 eye position signal could be used to take into account the sensory consequences of eye movements and map the fleeting positions of objects on the retina onto their stable position in the world.
Publisher: Elsevier BV
Date: 02-2012
Publisher: Frontiers Media SA
Date: 24-02-2016
Publisher: Elsevier BV
Date: 05-2019
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 2013
DOI: 10.1167/13.8.4
Publisher: Elsevier BV
Date: 06-2009
Publisher: Elsevier BV
Date: 08-2011
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 12-2011
DOI: 10.1167/11.14.11
Publisher: Springer Science and Business Media LLC
Date: 04-02-2022
Publisher: Society for Neuroscience
Date: 21-07-2010
Publisher: Elsevier BV
Date: 09-2016
Publisher: Society for Neuroscience
Date: 27-04-2011
DOI: 10.1523/JNEUROSCI.6255-10.2011
Abstract: Visual stimuli presented just before or during an eye movement are more difficult to detect than those same visual stimuli presented during fixation. This laboratory phenomenon—behavioral saccadic suppression—is thought to underlie the everyday experience of not perceiving the motion created by our own eye movements—saccadic omission. At the neural level, many cortical and subcortical areas respond differently to perisaccadic visual stimuli than to stimuli presented during fixation. Those neural response changes, however, are complex and the link to the behavioral phenomena of reduced detectability remains tentative. We used a well established model of human visual detection performance to provide a quantitative description of behavioral saccadic suppression and thereby allow a more focused search for its neural mechanisms. We used an equivalent noise method to distinguish between three mechanisms that could underlie saccadic suppression. The first hypothesized mechanism reduces the gain of the visual system, the second increases internal noise levels in a stimulus-dependent manner, and the third increases stimulus uncertainty. All three mechanisms predict that perisaccadic stimuli should be more difficult to detect, but each mechanism predicts a unique pattern of detectability as a function of the amount of external noise. Our experimental finding was that saccades increased detection thresholds at low external noise, but had little influence on thresholds at high levels of external noise. A formal analysis of these data in the equivalent noise analysis framework showed that the most parsimonious mechanism underlying saccadic suppression is a stimulus-independent reduction in response gain.
Publisher: Society for Neuroscience
Date: 24-07-2013
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 03-12-2010
DOI: 10.1167/10.14.1
Abstract: To study the effect of blur adaptation on accommodative variability, accommodative responses and pupil diameters in myopes (n = 22) and emmetropes (n = 19) were continuously measured before, during, and after exposure to defocus blur. Accommodative and pupillary response measurements were made by an autorefractor during a monocular reading exercise. The text was presented on a computer screen at 33 cm viewing distance with a rapid serial visual presentation paradigm. After baseline testing and a 5-min rest, blur was induced by wearing either an optimally refractive lens, or a +1.0 DS or a +3.0 DS defocus lens. Responses were continuously measured during a 5-min period of adaptation. The lens was then removed, and measurements were again made during a 5-min post-adaptation period. After a second 5-min rest, a final post-adaptation period was measured. No significant change of baseline accommodative responses was found after the 5-min period of adaptation to the blurring lenses (p > 0.05). Compared to the pre-adaptation level, both refractive groups had similar and significant increases in accommodative variability right after blur adaptation to both defocus lenses. After the second rest period, the accommodative variability in both groups returned to the pre-adaptation level. The results indicate that blur adaptation has a short-term effect on the accommodative system to elevate instability of the accommodative response. Mechanisms underlying the increase in accommodative variability by blur adaptation and possible influences of the accommodation stability on myopia development were discussed.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United States of America
No related grants have been discovered for Bart Krekelberg.