FiserLab Visual information processing and learning laboratory
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József Fiser
PI
Email Website
I am interested in understanding how humans and animals acquire a structured internal representation of their visual environment that is suitable for controlling sophisticated cognitive behavior.

In order to tackle such complex questions, I believe it is necessary to use an integrated approach that combines human behavioral studies of different ages, computational modeling, and the use electrophysiological methods in behaving animals.

My hope is that the synergy between these areas will lead us to novel insights in the domain of perceptually based visual cognition.

Ralf Haefner
PostDoc
Email
My research interests concern the question of how the brain extracts information about the world from the two images that fall onto our retinae (perceptual inference). Behaviorally relevant information is represented only very implicitly in the luminance values that make up those images and complex computations are required to make it explicitly available. In order to address this general question I am studying the model system of depth-from-stereo: how does the brain reconstruct a 3rd dimension from two 2D images? I am investigating the computations performed by binocular neurons in primary visual cortex - those neurons that are believed to compute 3D depth - and their read-out mechanism, i.e. how the information carried by populations of them is used to determine the distances to different objects, or their relative ordering. My tools are analytical and numerical models based on physiological data.
Pietro Berkes
PostDoc
Email Website
My main research interest concerns the way the brain forms a high-level representation of the environment from raw sensory input and without supervision. I approach this problem at a computational level in the framework of statistical inference and learning. I like to work from different perspectives, using machine learning models, analysis of electrophysiological data, and psychophysical experiments. My goal is to understand how neuronal populations support these probabilistic computations, what are the principles that guide their adaptation to the statistics of the environment, and how their final representation of the world is organized.
Kimberly MacKenzie
Graduate Student
Email
I graduated in 2000 from the University of Massachusetts Boston, and joined first the Masters program in 2006 and then the Neuroscience PhD program in 2007. My main research interest is how humans, especially infants, are able to make sense of what they see. I use statistical and rule learning paradigms in both infants and adults to look at how we build new visual representations, and also how those representations are stored in long-term memory. I'm particularly interested in what role sleep plays in the consolidation of statistically-learned memories.
Benjamin L. White
Graduate Student
Email
I graduated with a B.S. in biology from the University of Oregon in 2003, and defended my thesis on the attributes of sound stimuli that are necessary for the neuronal suppression of echoes in the inferior colliculus of barn owls. In the Fiser Lab, I am working on how visual stimuli are represented in the activity of small populations of neurons in the cortex, and how the distributions of activity change with specific types of learning, such as cross-modal cue-reinforcement association. Also, I am interested in relating these stimulus representations and learning-related changes to the patterns of spontaneous activity present in the brain in order to better understand how these two types of activity interact, and how learning alters the underlying activity structure of sensory systems.
Henry Galperin
Graduate Student
Email
I graduated from Case Western Reserve University in 2005 with a B.A. in Psychology. While an undergraduate, I studied how changes in vision with aging can impact cognitive performance. I was also involved in research on the physiological correlates of emotion regulation. My research in the Fiser Lab focuses on identifying the visual structures and dynamical tuning processes humans use to perceive their natural environment by using classical psychophysics along with eye-tracking systems and large-size displays. I am currently researching what role higher order correlations among basic scene attributes, such as orientation and contrast, may play in visual perception. I am also interested in exploring the neural correlates of visual perception using awake behaving animals and chronically implanted microwire electrodes.
Marjena Popović
PhD student
Email
I am interested in understanding the nature of internal representations in humans. There is increasing evidence that internal representations include uncertainty about sensory stimuli. I am interested in finding out if such representations of uncertainty exist in low levels of visual processing and if they are probabilistic in nature. I approach this issue from two perspectives: I conduct human behavioral experiments aiming to show that humans represent low-level visual stimuli alongside with the uncertainty associated with them, and I carry out electrophysiological experiments using behaving animals to explore the underlying neural coding of such representations.
Yang Chen
MSc student
Email
I graduated with a B.S. in psychology from Beijing Normal University, China in 2010. My undergraduate thesis was on the effect from stimulus category and handedness on human action facilitation. Currently, I am an MA student working on visual information processes under the condition of binocular rivalry. In an ongoing project, I use binocular rivalry to investigate the relationship between local and global levels of processing during visual bistability.
Dmitriy Lisitsyn
Lab assistant
Email
I was an undergraduate in the Fiser-lab between 2007-2008. Currently, I am a research assistant in the lab, working on eye movements during perception, measuring information content of neural codes, and implementing temporal Hidden Markov Models of human learning.
Grayce Selig
Undergraduate Student
Email
I am a psychology undergraduate research assistant in the Fiser-lab. I am interested in human learning and perception. In my project, I am using a novel generalized reverse correlation method to explore what the significant features in face perception are.
Anushka Aqil
Undergraduate Student
Email
I am a psychology undergraduate research assistant in the Fiser-lab. I am interested in the interaction between statistical learning, rule learning and sleep.

Alumni

Maolong Cui
Graduate Student
Email
I was a PHD student between 2008-2010 in the Cognitive Neuroscience program. I graduated from Shanghai Jiaotong University,Medicine School in China, and got a B.S. degree in biomedical engineering. My major interest is in higher-level inner representation of visual environment and scale invariant object recognition. I worked on data analysis of multichannel neural signal data and computational/statistical modeling of the performance of human subjects in psychophysical experiments.
Gergo Orban
PostDoc
Email
I was a Sloan-Swartz Postdoctoral Fellow in Theoretical Neuroscience in the Fiser-lab between 2006-2008 working on probabilistic models of visual leaning. Currently, I am a Marie-Curie Postdoctoral Fellow in Daniel Wolpert's lab in Cambridge UK.
Aaron Glick
Undergraduate Student
Email
I was a neuroscience undergraduate research assistant in the Fiser-lab between 2006-2008. I was also a Schiff-fellow and I completed my honor's thesis in the lab. My topic was 3-dimensional statistical learning and the link between eye movements and statistical learning. Currently, I am a research assistant in Yaoda Xu's Vision Science Laboratory at Harvard University.
Sarah Laredo
Undergraduate Student
Email
I was a psychology undergraduate research assistant in the Fiser-lab between 2005-2008, completing my honor's thesis in statistical learning of Gestalt rules in humans. Currently, I am a graduate student in Animal Behavior at the University of California at Davis, with Donald Owings. My main interest is in animal communication.
Benjamin White
Lab Assistant
Email
I have been lab manager in the Fiser-lab between 2006-2008. Currently I have a position with Eddie Harmon Jones, at Texas A&M University as the lab manager of the Social Emotive Neuroscience Lab.