Steven A. Fisher

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Recent physiological experiments have shown that the responses of many neurons in V1 and V3a are modulated by the direction of gaze. We have developed a neural network model of the hierarchy of maps in visual cortex to explore the hypothesis that visual features are encoded in egocentric (spatio-topic) coordinates at early stages of visual processing. Most(More)
BACKGROUND The heart develops under reduced and varying oxygen concentrations, yet there is little understanding of oxygen metabolism in the normal and mal-development of the heart. Here we used a novel reagent, the ODD-Luc hypoxia reporter mouse (oxygen degradation domain, ODD) of Hif-1α fused to Luciferase (Luc), to assay the activity of the oxygen(More)
How multicellular organisms obtain and use oxygen and other substrates has evolved over hundreds of millions of years in parallel with the evolution of oxygen-delivery systems. A steady supply of oxygen is critical to the existence of organisms that depend on oxygen as a primary source of fuel (i.e., those that live by aerobic metabolism). Not surprisingly,(More)
BACKGROUND AND PURPOSE Determining the role of vascular receptors in vivo is difficult and not readily accomplished by systemic application of antagonists or genetic manipulations. Here we used intravital microscopy to measure the contributions of sympathetic receptors, particularly α1-adrenoceptor subtypes, to contractile activation of femoral artery in(More)
The cardiac outflow tract (OFT) of birds and mammals undergoes complex remodeling in the transition to a dual circulation. We have previously suggested a role of myocardial hypoxia and hypoxia inducible factor (HIF)-1 in the apoptosis-dependent remodeling of the OFT. In the present study, we transduced recombinant adenovirus-mediated HIF-1alpha in embryonic(More)
Deep sequencing of RNA samples from rat small mesenteric arteries (MA) and aorta (AO) identified common and unique features of their gene programs. ~5% of mRNAs were quantitatively differentially expressed in MA versus AO. Unique transcriptional control in MA smooth muscle is suggested by the selective or enriched expression of transcription factors Nkx2-3,(More)
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