My published work is unified by having to do with time. My neuroscience projects have involved plasticity, in particular adaptation, spatiotemporal receptive field organization, and mechanisms underlying specificity. My early modeling research led to the hypothesis that inhibitory connections are strengthened in a Hebbian manner, so that cells with similar, rather than opposing, response properties inhibit each other. This notion has reappeared in my subsequent empirical work. Studies of development in normally and abnormally reared kittens represent one way to observe how the brain changes, but I have also concentrated on a somewhat different form of plasticity, adaptation.
Adaptation turns out to be a potent tool for investigating cortical connectivity.
These studies provided a powerful argument against the notion that cells with opposing response properties inhibit each other. The results indicated that even direction selective cells receive inputs from cells that respond in both directions. Theoretical work had shown how such bidirectional inputs can produce direction selectivity, via quarter-cycle phase differences between the inputs. The key insights from this work involved the importance of response timing, when a cell responds as opposed to how much it responds. Neurophysiologists have long been aware that the timing of a cell's activity influences signal processing, but few studies examined response timing quantitatively in the visual system.