Introduction Ebstein’s anomaly is associated with a wide range of cardiac dysrhythmias, including presence of 1 or more accessory pathways. We present a case of a girl with Ebstein’s anomaly and symptomatic tachycardia. Electrophysiology study demonstrated a slow conducting decremental pathway as well as inducible antidromic reentrant tachycardia. Voltage mapping of the pathway potential was pe...

OBJECTIVES This study was designed to determine the sensitivity and specificity of concealed entrainment (CE) for the identification of a critical isthmus in the atrium. BACKGROUND Isthmus identification during entrainment mapping of macro-reentrant atrial tachycardia (MRAT) relies on the demonstration of CE. METHODS Using the model of typical atrial flutter, entrainment was performed in 10...

Early electrophysiological studies in the mammalian hippocampus reported that orthodromic depolarization of pyramidal cells evoked action potential discharge (presumed Na+ dependent) both at the axon hillock and at one or more sites in the dendritic arborization (Cragg and Hamlyn, 1955; Andersen, 1959, 1960; Spencer and Kandel, 1961; Andersen and Lomo, 1966). Although tetrodotoxin (TTX)-sensiti...

1. Inhibitory connections of X- and Y-type principal cells in the cat's dorsal lateral geniculate nucleus were studied with intracellular recording techniques in barbiturate-anaesthetized animals. Cells were identified as principal cells by antidromic activation from the visual cortex and as X or Y types by their responses to visual stimulation. 2. Graded electrical stimulation was used to obta...

The amygdala and bed nucleus of the stria terminalis (BNST) are thought to subserve distinct functions, with the former mediating rapid fear responses to discrete sensory cues and the latter longer "anxiety-like" states in response to diffuse environmental contingencies. However, these structures are reciprocally connected and their projection sites overlap extensively. To shed light on the sig...

Spikes were evoked in rat olfactory sensory neuron (OSN) populations by electrical stimulation of the olfactory bulb nerve layer in pentobarbital anesthetized rats. The latencies and recording positions for these compound spikes showed that they originated in olfactory epithelium. Dual simultaneous recordings indicated conduction velocities in the C-fiber range, around 0.5 m/s. These spikes are...

Nucleus retroambiguus (NRA), in the caudal medulla, projects to all spinal levels. One physiological role is abdominal pressure control, evidenced by projections to intercostal and abdominal motoneurons from expiratory bulbospinal neurons (EBSNs) within NRA. The roles of NRA projections to the lumbosacral cord are less certain, although those to limb motoneurons may relate to mating behavior an...

THE EXPERIMENTS of Muller (18) and others demonstrated that stimulation of the central end of a severed ventral spinal root does not result in the production of muscular movements; that is to say, an antidromic volley of impulses in a group of motor axons does not result in the discharge of other motoneurons. However, such antidromic volleys are not without effect on the spinal cord. It is well...

The first study, described in the companion article, reports that acute exposure of rat hippocampal slices to either hyperbaric oxygen (HBO: 2.84 and 4.54 atmospheres absolute, ATA) or normobaric reoxygenation (NBOreox; i.e., normobaric hyperoxia: 0.6 or 0.0→0.95 ATA) stimulates synchronous orthodromic activity in CA1 neurons, which includes activation of O2-induced potentiation (OxIP) and, in ...