Dr. Charles Gilbert Profile
A member of the National Academy of Sciences and the American Academy of Arts and Sciences, with numerous awards and recognitions, including the W. Alden Spencer Award from the Columbia University College of Physicians and Surgeons.
A Rita Allen Foundation Scholar and member of the Rita Allen Foundation Scientific Advisory Committee, and a graduate of Harvard Medical School with a Doctor of Medicine degree as well as a Ph.D.
Held an academic appointment at Harvard until he joined the faculty of Rockefeller University, where he heads the Laboratory of Neurology and is the Arthur and Janet Ross Professor.
As part of a series of profiles illuminating our Rita Allen Foundation Scholars, their careers, accomplishments and aspirations, Dr. Gilbert recently shared some of his thoughts with Rita Allen Foundation President and Chief Executive Officer Elizabeth Good Christopherson.
Ms. Christopherson: Will you tell us your pathway to a career in science and research, and who are your mentors?
Dr. Gilbert: It seems I was always interested in science and biomedical research, even at an early age. I recall being as young as 4 years old and wanting to be a research scientist. I think it stemmed from my visits to the doctor and wanting to invent a vaccine shot that did not hurt. I was also inspired by books about scientific research, such as Arrowsmith by Sinclair Lewis, where the fictional character worked as a physician-researcher at an institute modeled on The Rockefeller University. I had forgotten the connection when I first began working at Rockefeller, and it is ironic that it had such an influence and I ended up working here.
I had my first research experiences during college, where I worked at the Cold Spring Harbor laboratory. The work I did there was at the molecular level, but after a time my interests migrated towards doing something more systems oriented. I was fortunately able to tailor my own program to pursue my degrees at Harvard, where I worked with Torsten Wiesel and David Hubel, who did seminal work on neural systems research, and for which they received the Nobel Prize. From that time to the present, I have had a continuing interest studying the circuitry underlying the processing of sensory information by the cerebral cortex.
Today, my team and I at Rockefeller study the primary visual cortex, a region of cells at the back of the brain and the site of the initial stage of cortical processing of information. The job of the visual cortex is to take signals coming from the retina, group features of visual scenes belonging to objects, and determine their shapes. We investigate the mechanism, at the level of cortical circuitry, by which this occurs.
We have discovered a plexus of long-range horizontal connections that mediate the assembly of contours and the parsing of visual scenes into objects and background. We also found close correspondence between the geometry of these connections, the functional properties of visual cortical neurons and the perception of visual stimuli.
Perceptual Learning, the way visual experience shapes the strategy by which the cortex analyzes sensory information, is another major interest of ours. We examine the contributions of different cortical areas along the visual pathway that facilitate this learning and are characterizing the functional changes occurring at the level of individual neurons.
We knew that in very young children there was a limited time window, known as the critical period, for certain kinds of experience dependent changes to occur. We now know that, even in adults, the visual cortex is capable of altering its functional properties and circuitry in response to visual experience. These long-term changes aid in analyzing visual scenes and as a result, normal visual experience can play a role in functional recovery after damage of the central nervous system.
Our work has demonstrated that the properties of the visual cortex reflect both sensory and behavioral contexts, suggesting that each cortical area is an adaptive processor that runs different programs according to the immediate demands of the perceptual task. Object recognition, for example, involves a countercurrent process of feedforward and feedback interactions. The top-down signal conveys information about attentional locus, perceptual task and object expectation. These results led to a novel view of cortical processing: Rather than having fixed functional properties, adult neurons are dynamically tuned, changing their functional roles over the long term with varying sensory experience and over the short term with changing behavioral contexts.
Ms. Christopherson: What issues are priorities for you in the future?
Dr. Gilbert: Going forward, it is clear that much of the key to understanding neurological systems requires one to understand brain function at the level of circuitry. A number of new experimental approaches are making it increasingly possible to study the biophysics of cortical circuits in the intact, functioning nervous system. In addition, computational approaches are facilitating our understanding of how the brain works as a complex interactive and dynamic system, and to link the activity of neuronal ensembles to perception.
On the horizon, a more thorough understanding the role of top-down interactions in sensory processing is likely to provide insight into behavioral disorders such as schizophrenia and autism, which have been suggested to be “disconnection syndromes,” or a dysfunction of top-down interactions between areas of the cerebral cortex.
We are also facilitating the use electrophysiology, imaging and molecular approaches to understand the mechanisms of adult cortical plasticity. We have been able to study the contribution of different neuronal types and circuit components to experience dependence changes in cortical function. We have looked at the circuitry and synaptic mechanisms underlying the dynamic changes in functional properties of cortical cells in behaving animals. Electrophysiological recordings are used to study the more complex properties of cortical cells and their dependence on top-down influences and perceptual learning. We also use human psychophysics to explore the perceptual consequences of dynamic changes in cortical properties.
Ms. Christopherson: What do you think are the major opportunities and challenges facing research scientists?
Dr. Gilbert: Having served on several study sections for National Institutes of Health (NIH) grants and also just recently for the council for the National Eye Institute, my concerns and hopes center on the availability of funding for research.
The contraction in the federal budget is having a direct impact on the nature of the work being done. The limited funding available tends to make scientists less willing to take risks, and the research enterprise becomes less forward looking. Also, society as a whole must develop an understanding of the nature of scientific theories, to appreciate the necessity for taking a long view in getting solutions to scientific problems, and allow public policy to be based on sound scientific principles. Public education is the key and we must do a better job of explaining the nature of science and the scientific enterprise.
Ms. Christopherson: As a Rita Allen Foundation Scholar yourself and member of our Scientific Advisory Committee, which is an integral part of the Scholar selection process, what do you believe are strengths of the program?
Dr. Gilbert: My own experience as a Scholar is an example of how important freedom and the flexibility to try new things are to a researcher. I had the flexibility to test new ideas and approaches.
The Rita Allen Foundation also lends a level of prestige that allows the researchers to leverage more support within and from outside their institutions. It is considered a valued recognition in the field.
In addition, it is often difficult for even the best scientists to receive support early in their careers and the Rita Allen Foundation seeks out early stage research and innovative work.