White BL. & Fiser J. (2008) The relationship between awake and anesthetized neural responses in the primary visual cortex of the rat. SFN 2008, Washington, DC [Abstract]
Much of what we know about visual processing in the brain is based on neural data collected in anesthetized animals assuming that the essential aspects of the computations are preserved under such conditions. However, recent findings support an alternative view that visual processing depends upon ongoing activity, which is significantly altered in anesthetized preparations. Therefore, […]
Popovic M., Lisitsyn D., Lengyel M. & Fiser J. (2011) Simultaneous representation of uncertainty about multiple low-level visual elements. EVCP 2011, Perception 40, 190-190 [Abstract]
Recent findings suggest that humans represent uncertainty for statistically optimal decision making and learning. However, it is unknown whether such representations of uncertainty extend to multiple low-level elements of visual stimuli, although this would be crucial for optimal probabilistic representations. We examined how subjects’ subjective assessment of uncertainty about the orientations of multiple elements in […]
MacKenzie K. & Fiser J. (2009) The emergence of explicit knowledge with experience in visual statistical learning. VSS 2009, Journal of Vision 9 (8), 883-883 [Abstract]
Visual statistical learning has been established as a paradigm for testing implicit knowledge that accumulates gradually with experience. Typically, subjects are presented with a stream of scenes composed of simple shapes arranged according to co-occurrence rules. Subjects observe the scenes without a defined task, and during the test subjects’ familiarity with the building blocks of […]
Cui M., Fontanini A., Katz DB. & Fiser J. (2008) Characterizing internal dynamic states and their emergence in the primary visual cortex of the awake ferret. SFN 2008, Washington, DC [Abstract]
According to recently emerging views on visual cortical processing, activity in the primary visual cortex is governed by dynamically changing internal states of the system modulated by the incoming information rather than being fully determined by the visual stimulus. We analyzed systematically the dynamical nature of these states and the conditions required for their emergence. […]
Fiser J., Berkes P., Orban G. & Lengyel M. (2011) Probabilistic computation: a possible functional role for spontaneous activity in the cortex. ECVP 2011, Perception 40, 53-53 [Abstract]
Although a number of recent behavioral studies implied that the brain maintains probabilistic internal models of the environment for perception, motor control, and higher order cognition, the neural correlates of such models has not been characterized so far. To address this issue, we introduce a new framework with two key ingredients: the “sampling hypothesis” and […]
McIlreavy L., Fiser J. & Bex PJ. (2009) Visual field loss, eye movements and visual search. VSS 2009, Journal of Vision 9 (8), 1210-1210 [Abstract]
Objectives: In performing search tasks, the visual system encodes information across the visual field and deploys a saccade to place a visually interesting target upon the fovea. The process of saccadic eye movements, punctuated by periods of fixation, continues until the desired target has been located. Loss of peripheral vision restricts the available visual information […]
MacKenzie K., Fortis-Santiago Y. & Fiser J. (2007) Integrating central and peripheral information during object categorization. VSS 2007, Journal of Vision 7 (9), 194-194 [Abstract]
Images presented at fixation provide more information to the visual system than images presented parafoveally. However, it is not clear whether it is more beneficial to receive the larger amount of information first in sequential categorical comparisons. Theories based on activation of mental sets, pure information content, or interference make different predictions on the likely […]
MacKenzie KJ., Aslin RN. & Fiser J. (2011) The interaction between chunking and stimulus complexity in infant visual statistical learning. VSS 2011, Journal of Vision 11 (11), 459-459 [Abstract]
Human infants are known to learn statistical regularities of the sensory environment implicitly in various perceptual domains. Visual statistical leaning studies have illustrated that this learning is highly sophisticated and well_approximated by optimal probabilistic chunking of the unfamiliar input. However, the emergence and unitization of such perceptual chunks at an early age and their relation […]
Glick A. & Fiser J. (2009) The less-is-more principle in realistic visual statistical learning. VSS 2009, Journal of Vision 9 (8), 877-877 [Abstract]
While in previous studies, a number of abstract characteristics of visual statistical learning have been clarified under various 2-dimesional settings, little effort was directed to understand how real visual dimensions in 3-dimensonal scenes interact during such learning. In a series of experiments using realistic 3D shapes and the dimensions of color, texture, and motion, we […]
Galperin H., Bex P. & Fiser J. (2007) Human orientation sensitivity during object perception. VSS 2007, Journal of Vision 7 (9), 587-587 [Abstract]
The accurate representation of local contour orientation is crucial for object perception, yet little is known about how humans encode this information while viewing complex images. Using a novel image manipulation method, we assessed sensitivity to the local orientation structure of natural images of differing complexity. We found that the visual system involuntarily discounts substantial […]