The low-threshold spike (LTS), generated by the transient Ca(2+) current I(T), plays a pivotal role in thalamic relay cell responsiveness and thus in the nature of the thalamic relay. By injecting depolarizing current ramps at various rates to manipulate the slope of membrane depolarization (dV/dt), we found that an LTS occurred only if dV/dt exceeded a minimum value of approximately 5-12 mV/se...

Following AVN ablation, eight dogs were surgically instrumented for chronic (continuous) HIS-bundle pacing. For data collection, implanted pacemakers were transiently programmed to pace in stepwise ascending ramps at rates from 50 to 200 beats/min in 30-beat/min steps. Each rate was held for 60 seconds. At each rate, ECG signals were collected from conscious dogs for measurements of QT interval...

We investigated autonomic control of cardiovascular function in able-bodied (AB), paraplegic (PARA), and tetraplegic (TETRA) subjects in response to head-up tilt following spinal cord injury. We evaluated spectral power of blood pressure (BP), baroreflex sensitivity (BRS), baroreflex effectiveness index (BEI), occurrence of systolic blood pressure (SBP) ramps, baroreflex sequences, and cross-co...

Repetitive, brief target ramp movements every few seconds lead to anticipatory acceleration before each ramp onset and anticipatory deceleration before ramp offset. We assessed whether identifying novel changes in the pursuit target would alter this pattern of anticipatory pursuit. Without target identification (TI), anticipatory acceleration increased when intervals between ramps were regular,...

The visual accessibility of a space refers to the effectiveness with which vision can be used to travel safely through the space. For people with low vision, the detection of steps and ramps is an important component of visual accessibility. We used ramps and steps as visual targets to examine the interacting effects of lighting, object geometry, contrast, viewing distance, and spatial resoluti...

Extracellular excitation of neurons is applied in studies of cultured networks and brain tissue, as well as in neuroprosthetics. We elucidate its mechanism in an electrophysiological approach by comparing voltage-clamp and current-clamp recordings of individual neurons on an insulated planar electrode. Noninvasive stimulation of neurons from pedal ganglia of Lymnaea stagnalis is achieved by def...

The calcium-sensing receptor (CaSR) is a class III G-protein-coupled receptor (GPCR) that responds to changes in extracellular calcium concentration and plays a crucial role in calcium homeostasis. The mechanisms controlling CaSR trafficking and surface expression are largely unknown. Using a CaSR tagged with the pH-sensitive GFP super-ecliptic pHluorin (SEP-CaSR), we show that delivery of the ...

The purpose of this study was to identify the instability of the trunk and the pelvis of subjects who were standing on differently angled ramps under conditions in which the ramps were crossed. Changes in the trunk and the pelvis while each subject was standing on one leg in the direction of the cross ramps at four angles (0°, 5°, 10°, and 15°) were measured. To identify instability, the trunk ...

Spatial data, either areal or geostatistical (point-referenced), are becoming increasingly utilized in the study of many scientific fields due to the accessibility of data monitoring systems and associated datasets. When both types of data are available for the same underlying spatial process, computationally efficient and statistically sound methods are needed for their joint analysis. Markov ...

The calcitonin receptor-like receptor (CRLR) can function as either a receptor for calcitonin gene-related peptide (CGRP) or for adrenomedullin (ADM), depending upon the coexpression of a novel family of single transmembrane proteins, which we have called receptor activity modifying proteins or RAMPs. RAMPs 1, 2, and 3 transport CRLR to the plasma membrane with similar efficiencies, however RAM...