Experiments were performed on the hearts of open-chest anesthetized dogs and on isolated rabbit hearts. Intracellular microelectrodes and bipolar surface electrodes were used for recording from and for stimulating the atria, AV node, bundle of His, bundle branches and ventricles. Atrial or ventricular premature beats which were usually blocked or delayed within the AV node were facilitated when...

DP is a top-down theorem prover for supernormal or Poole-type defaults. Axioms and defaults can be arbitrary clauses, i.e. it supports disjunctions and (real) classical negation. Multiple disjunctions can be handled credulously, skeptically, and carefully. In skeptical mode, the expressivity of supernormal defaults corresponds to variable circumscription. The system is based on model eliminatio...

Animal models continue to improve our understanding of tinnitus pathogenesis and aid in development of new treatments. However, there are no diagnostic biomarkers for tinnitus-related pathophysiology for use in awake, freely moving animals. To address this disparity, two complementary methods were combined to examine reliable tinnitus models (rats repeatedly administered salicylate or exposed t...

A supernormal period of intraand interatrial conduction was observed in five patients during premature stimulation of various atrial sites with driving cycle lengths ranging between 500 and 600 msec. Electrograms were recorded with filtered, 1-mm apart, bipolar catheter electrodes placed in the high right atrium, coronary sinus, and midleft atrium. The supernormal period, which lasted from 90 t...

The effects of early monocular form deprivation on the developing mammalian visual system, and the anatomical and physiological consequences of early monocular enucleation, suggest that the remaining eye of human subjects who had the other eye removed early during development might be capable of supernormal performance. To test this inference, the achromatic contrast sensitivity of the remainin...

Three patients with a bull's-eye macular lesion and other signs characteristic of cone dystrophy gave an unusual ERG finding. In response to a white flash of moderate intensity the scotopic b-wave amplitude was considerably larger than normal. One patient had elevated rod thresholds and nyctalopia, while the other 2 had normal rod sensitivity associated with the supernormal scotopic b-wave ampl...

PURPOSE We report a psychophysical investigation of 5 observers with the retinal disorder "cone dystrophy with supernormal rod ERG," caused by mutations in the gene KCNV2 that encodes a voltage-gated potassium channel found in rod and cone photoreceptors. We compared losses for rod- and for cone-mediated vision to further investigate the disorder and to assess whether the supernormal ERG is ass...

Relative contributions of the atria and the atrioventricular (AV) node to AV conduction were studied in isolated, blood-perfused dog hearts. The functional refractory period of the atria, although shorter than that of the AV node, determined the functional refractory period of the entire transmission system in 50% of the hearts. Slow atrial conduction of early beats greatly influenced the shape...