Scholars@Duke
David Fitzpatrick

David Fitzpatrick

James B. Duke Distinguished Professor Emeritus of Medicine
Neurobiology
fitzpat@neuro.duke.edu
Box 3209 Med Ctr, Durham, NC 27710
427C Bryan Res Bldg, Durham, NC 27710

Overview

Research in the Fitzpatrick lab is focused on understanding the functional organization and development of circuits in primary visual cortex, an important component of the vast network of neural centers that are involved in processing visual information and the first site along the visual pathway where neurons exhibit selectivity for stimulus attributes such as the orientation of edges and the direction of motion of objects. Our research combines optical imaging, intracellular recording and neural tracing techniques to explore how stimulus features are represented in the activity of identified neural circuits. Our work on the development of visual cortex suggests that normal sensory experience is required to complete the maturation of properties that are first established by experience-independent mechanisms. In another series of experiments we are addressing how feedforward and recurrent circuits contribute to the orientation selective responses of individual neurons. Our results indicate a remarkable specificity in the spatial arrangement of the axonal arbors associated with these two systems, a specificity that imparts an axial bias to the way these neurons sample information from visual space both within and beyond their classical receptive field. In another set of experiments, we are exploring how different combinations of stimulus features such as orientation, direction of motion and speed are represented in the population response of visual cortical neurons. Contrary to the conventional view that activity patterns in visual cortex can be explained as the intersection between multiple stimulus feature maps, our results indicate that population activity is best explained as a single spatiotemporal transform in which orientation, direction of motion and speed are combined. Current efforts are directed at understanding the temporal dynamics of this spatiotemporal transform and the way in which it is altered by changes in luminance and contrast.

Current Appointments & Affiliations

James B. Duke Distinguished Professor Emeritus of Medicine · 2011 - Present Neurobiology, Basic Science Departments
Professor Emeritus of Neurobiology · 2011 - Present Neurobiology, Basic Science Departments

In the News

Published April 21, 2015
For baboons, there's more to love than just big butts

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Recent Publications

A morphological basis for orientation tuning in primary visual cortex.

Journal Article Nat Neurosci · August 2004 Featured Publication Feedforward connections are thought to be important in the generation of orientation-selective responses in visual cortex by establishing a bias in the sampling of information from regions of visual space that lie along a neuron's axis of preferred orienta ... Full text Link to item Cite

The contribution of vertical and horizontal connections to the receptive field center and surround in V1.

Journal Article Neural Netw · 2004 Here we review the results of anatomical and physiological studies in tree shrew visual cortex which focus on the contribution of vertical and horizontal inputs to receptive field center and surround properties of layer 2/3 neurons. A fundamental feature o ... Full text Link to item Cite

Mapping multiple features in the population response of visual cortex.

Journal Article Nature · June 26, 2003 Featured Publication Stimulus features such as edge orientation, motion direction and spatial frequency are thought to be encoded in the primary visual cortex by overlapping feature maps arranged so that the location of neurons activated by a particular combination of stimulus ... Full text Link to item Cite
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Recent Grants

Non-invasive Chemical Genetic Control of Neuronal Activity

ResearchCollaborator · Awarded by National Institutes of Health · 2009 - 2014

Functional Organization of Visual Cortex

ResearchPrincipal Investigator · Awarded by National Institutes of Health · 1998 - 2011

The Development of Direction Selectivity in Visual Cortex

ResearchPrincipal Investigator · Awarded by National Institutes of Health · 1996 - 2011

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Education, Training & Certifications

Duke University · 1982 Ph.D.