J Anthony Movshon - US grants

DESCRIPTION (provided by applicant): The Center for Neural Science at New York University is a premier site for research on functional aspects of vision. Eighteen investigators from the Center request support for their vision research through continuation of a Core Grant. They are bound together by their research Interests In the neural and behavioral bases of vision and visually guided behavior. The proposed Core will comprise of four modules, each of which will benefit research in the research areas represented by program faculty: 1. A Visual Displays Module which will provide support for the development of state-of-the-art software for the generation of a wide variety of visual stimuli for psychophysical, neurophysiological, and brain experiments. 2. A Design and Fabrication Module which will provide expertise to design and build novel electronic and mechanical devices such as theose required for multielectrode recording in the visual cortex, noninvasive methods of eye movement recording, and Interface devices for behavioral and blloglcal experiments. 3. A Neuroanatomy and Molecular Biology Module which will provide expert support for the processing of neuroanatomlcal material at both the light and EM level, for the analysis and localization of electrophysiological recording sites In histological material, and for the creation of transgene-containing viruses to modify neuronal funtlon experimentally. 4. A Functional Imaging Module which will provide support for hardware and software services for users of the Siemens MRI scanner and associated devices In the Center for Brain Imaging, giving access for Core researchers to functional and structural Imaging capabilities for human and animal research.

DESCRIPTION (provided by applicant): The goal of our research is to uncover the cortical computations that support the functions of the extrastriate visual areas of the cerebral cortex. Our approach is to create functional models of cortical processing, and fit them to data recorded from single neurons. Functional models are designed to account for the visual response properties of neurons as economically as possible. These models do not necessarily reflect the details of neuronal circuitry, but have an overall organization that seeks to be consistent with known structures and neuronal connections. We will focus on an important area in the extrastriate cortex, MT (or V5). MT contains a high concentration of directionally selective neurons and is specialized for the analysis of visual motion. To study processing in MT, we need to know the properties of the neurons that transmit information to it, how that information is integrated, and how that integration is affected by the context in which the information is presented. MT is heavily dependent on input from V1 for its visual responsiveness, and receives direct inputs from directionally selective neurons in V1. Information can also reach MT through several indirect relays, and there is evidence that these different relays carry different sorts of visual information. First, we will identify and characterize the V1 and V2 neurons that provide the major specific functional input to MT, to provide a more complete account of the information reaching MT. Second, we will incorporate this knowledge into an existing but limited functional model of MT, which we will challenge with a set of novel multi-component stimuli. Our goal is to extend the model so that it can explain such essential features of neuronal responses as their dependence on the integration of motion information over space and time. The development and elaboration of this model will motivate the development of new mathematical techniques for model fitting, and will also form the basis for the subsequent development of models for visual responses in other extrastriate areas. Finally, we will use the knowledge gained in elaborating the functional model of MT to explore the role of the contextual modulations of MT activity that can be evoked by stimuli delivered to the region surrounding the classical receptive field. The work proposed will advance the overall goal of understanding cortical computation in the visual system by bringing to bear on the extrastriate cortex a set of tools and methods that have had many signal successes in probing primary visual cortex function. PUBLIC HEALTH RELEVANCE: Disorders of the visual nervous system are a major cause of visual disability. Damage to the primary visual processing area of cortex (V1) causes a loss of conscious vision over part or all of the visual field. This profound disability is considered irremediable. Parts of the visual cortex outside V1 may, however, be able to substitute for some lost functions after V1 damage, a phenomenon known as blindsight. Other disorders affect these same areas outside V1, and cause other forms of visual loss such as akinetopsia (motion blindness) and agnosia (form blindness). Our research seeks to understand the organization and function of the cortical visual areas beyond primary cortex, both because of their potential as substrates for visual loss and recovery after brain damage, and because they are where sensory data are transformed into signals that form decisions, guide actions, and create enduring memories of evanescent events.

Project Summary/Abstract This is a competing renewal application for funds to support pre- and postdoctoral training in visual neuroscience at New York University in the Center for Neural Science (CNS) and the Cognition and Perception Program in the Department of Psychology (CP). We seek to renew training support for 6 predoctoral and 1 postdoctoral fellows. This level of support is justified by the need for the training program to provide for the training of a diverse yet coherent group of trainees. With the help of previous NEI support, the Visual Neuroscience Training Program has become a leading center for research training and has launched and shaped the careers of many who have made important contributions to the field. The 20 faculty of the training program seek to understand the visual system from a variety of disciplinary perspectives, but all share a consistent focus on understanding visual function. The quality, experience, breadth, and productivity of the training faculty has in the past and will in the future provide a fertile intellectual environment in which young scientists can thrive. Three newly recruited faculty have invigorated the program and made it even better, and have broadened its reach into the general area of visual disorders. There is ample instruction through courses and especially through mentoring in the research labs of CNS and CP that helps bring trainees to the frontiers of vision research. Many active researchers supported by NEI and other agencies provide direction, leadership, and support for students once they emerge as more independent senior scholars. Extensive shared facilities, including MRI scanners, an MEG and a TMS facility operated solely for research the two participating departments, facilitate collaborations among faculty and trainees. The students who join the CNS and CP doctoral programs are of outstanding quality and a very high proportion have historically gone on to successful and in some cases stellar careers in visual neuroscience.

DESCRIPTION (provided by applicant): The goal of this research is to discover the cortical computations embodied in the responses of neurons in ventral visual area V2. Since V2 is heavily dependent on input from V1 for its visual responsiveness, we will develop a two-stage model, in which responses are constructed from a suitable combination of V1 afferents, with the design of each stage following a common canonical form. This model is intended to account for the visual response properties of neurons as economically as possible, while not necessarily reflecting the details of neuronal circuitry. This simplicity is deliberate, as it will allow the mdel to be fit to data recorded from single neurons, and, when assembled into a population, to predict perceptual capabilities. The motivation for the structure of the model, and our confidence in its success, comes from the convergence of three strands of previous work: (1) we have developed, fit, and validated a similar two-stage model for neuronal responses in area MT, a dorsal stream area which also receives primary afferent drive from area V1; (2) we have developed a two-stage model for visual texture representation that captures perceptually recognizable structures of natural images using spatial integration regions matched in size to those of V2 cells. We've shown that images synthesized to have matching model responses are indistinguishable to human observers; and (3) we've obtained preliminary data indicating that most of V2 cells respond more vigorously to synthetic texture stimuli than to spectrally matched noise stimuli, whereas V1 cells do not. The research is divided into three parts. First, we will gather electrophysiological data to dissect those model-generated features that underlie the increased responsiveness of V2 to texture stimuli. We will, in parallel, gather evidence for the increased responsiveness using fMRI, which will allow us to compare simultaneously measured responses averaged over neural populations in V1 and V2. Second, we will develop a physiologically plausible instantiation of the texture model and develop the methods to fit it to data from single neurons. Finally, we will link the novel functional response properties we have discovered to perception by simultaneously measuring neuronal responses and perceptual judgments in awake behaving macaques. To explore sensitivity to naturalistic features, we will relate psychometric and single-neuron neurometric functions, and use choice probability to link responses to behavioral performance.

? DESCRIPTION (provided by applicant): The Center for Neural Science at New York University is a premier site for research on functional aspects of vision. Eighteen investigators from the Center request support for their vision research through continuation of a Core Grant. They are bound together by their research interests in the neural and behavioral bases of vision and visually guided behavior. The proposed Core will comprise four modules, each of which will benefit research in the research areas represented by program faculty: a Visual Displays Module, a Design and Fabrication Module, a Neuroanatomy Module, and a Functional Imaging Module.

? DESCRIPTION (provided by applicant): A central goal of visual neuroscience is to understand how the brain supports perception. A powerful approach to studying the relationship between brain function and perception is to study the processes in parallel during development. Visual function is poor in infants and emerges over different developmental trajectories depending on the type of visual function. The distinct developmental time courses for different functions provide a unique opportunity to directly evaluate the link between brain development and perception, provided there is a clear hypothesis about the neural underpinnings of the perceptual ability. We have identified such a connection between perception of natural scenes and visual forms, and areas V2 and V4 in the primate brain. We propose three interrelated sets of experiments to explore the links between the development of naturalistic texture sensitivity and the functional development of these visual areas. First, we will study psychophysical and non-invasive high-density evoked response measures of sensitivity to texture and form stimuli longitudinally in individual infant macaques, to elucidate the developmental time courses for this perceptual ability. We propose the hdEEG assay as an adjunct to the psychophysics which can bridge our results directly to human infants. Second, we will directly assess neurophysiologically the development of neural response properties and receptive field organization of area V2 and the specific responses of V2 neurons to the same natural and naturalistic texture stimuli. We will use both anesthetized and awake preparations to fully characterize this process. The awake recordings will be conducted in parallel with behavioral assays in the same individuals to directly correlate behavioral and neural development. Third, we will study the development of neural sensitivity of area V4 to natural scenes and their underlying statistical properties, as well as thir ability to differentially signal the structure of suitable form stimuli. These experiments will advance our understanding of the role of V2 and V4 in support of 1) perceptual organization abilities, such as scene segmentation, object recognition, and global form perception, 2) the cascade of information processing between primary visual cortex and downstream object processing areas such as IT, and 3) the limitations that neural development pose on the development of perception and cognition. Our greater goal is to elucidate the mechanisms by which the ventral stream processes form information and parses natural scenes.

Abstract The Director of the Vision Core will be Anthony Movshon, assisted by an Executive Committee consisting of the four module directors, two departmental administrators, and an outside advisor, David Williams of the University of Rochester. The Director and the Executive Committee will oversee the operation and allocation of Core resources.

Abstract The Director of the Vision Core will be Anthony Movshon, assisted by an Executive Committee consisting of the four module directors and/or their four associate directors, and two outside advisors, David Williams of the University of Rochester and Dennis Levi of the University of California at Berkeley. The Director and the Executive Committee will oversee the operation and allocation of Core resources.

Abstract The Neuroanatomy Module provides essential support for the Vision Core in three main areas: 1) Histological and immunohistochemical tissue processing; 2) Anatomical imaging, data acquisition and image analysis; 3) Preparation of viral vectors for optogenetic manipulation of neuronal signals. The Neuroanatomy Module provides moderate or extensive support for 13 members of the Vision Core, including one young investigator and 7 NEI funded investigators holding qualifying R01 grants.