Galperin H., Bex P. & Fiser J. (2009) Orientation integration in complex visual processing. VSS 2009, Journal of Vision 9 (8), 1020-1020a [Abstract]
How does the visual system integrate local features to represent global object forms? Previously we quantified human orientation sensitivity in complex natural images and found that orientation is encoded only with limited precision defined by an internal threshold that is set by predictability of the stimulus (VSS 2007). Here we tested the generality of this […]
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 […]
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. & 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 […]
Berkes P., Orbán G., Lengyel M. & Fiser J. (2009) Neural evidence for statistically optimal inference and learning in the primary visual cortex. SFN 2009, Chicago, IL [Abstract]
How do we infer from sensation the state of the external world? Humans and animals have been shown to perform statistically optimal inference and learning during perception in the presence of noise and uncertainty in the presented stimuli. This points to a probabilistic representation of the sensory input, where evidence coming from sensation is optimally […]
Berkes P., Wood F. & Pillow J. (2009) Characterizing neural dependencies with copula models. NIPS 2009, NIPS Conference Abstracts 119-136
The coding of information by neural populations depends critically on the statistical dependencies between neuronal responses. However, there is no simple model that can simultaneously account for (1) marginal distributions over single-neuron spike counts that are discrete and non-negative; and (2) joint distributions over the responses of multiple neurons that are often strongly dependent. Here, […]
Berkes P., White B. & Fiser J. (2009) No evidence for active sparsification in the visual cortex. NIPS 2009, NIPS Conference Abstracts 108-116 [Abstract]
The proposal that cortical activity in the visual cortex is optimized for sparse neural activity is one of the most established ideas in computational neuroscience. However, direct experimental evidence for optimal sparse coding remains inconclusive, mostly due to the lack of reference values on which to judge the measured sparseness. Here we analyze neural responses […]
White BL., Berkes P. & Fiser J. (2010) Suppression of intrinsic cortical response variability is state- and stimulus-dependent, Frontiers in Systems Neuroscience. Conference Abstract: Computational and systems neuroscience, 2010.
Neural responses to identical sensory stimuli can be highly variable across trials, even in primary sensory areas of the cortex. This raises the question of how such areas reliably transmits sensory-evoked responses to guide appropriate behavior. Internally-generated, spontaneous activity, which is ubiquitous in the cortex, is a leading candidate for causing much of the observed […]
Berkes P., David SV., Fritz J., Shamma SA. & Fiser J. (2010) Neural activity as samples from a probabilistic representation: evidence from the auditory cortex., Frontiers in Systems Neuroscience. Conference Abstract: Computational and systems neuroscience, 2010.
In the past years, there has been a paradigm shift in the field of cognitive neuroscience as a number of behavioral studies demonstrated that animals and humans can take into account statistical uncertainties of task, reward, and their own behavior, in order to achieve optimal task performance. These results have been interpreted in terms of […]
Cui M., Katz DB., Fontanini A. & Fiser J. (2010) The flow of expected and unexpected sensory information through the distributed forebrain network, Frontiers in Systems Neuroscience. Conference Abstract: Computational and systems neuroscience, 2010.
Forebrain taste information processing is accomplished mainly by three reciprocally connected forebrain regions -primary gustatory cortex (GC), (basolateral) amygdala (AM), and orbitofrontal cortex (OFC)- loosely characterized as the neural sources of sensory, palatability-related, and cognitive information, respectively. It has been proposed that the perception of complex taste stimuli involves an intricate flow of information between […]