Digital Museum of Retinal Ganglion Cells with Dense Anatomy and Physiology.

When 3D electron microscopy and calcium imaging are used to investigate the structure and function of neural circuits, the resulting datasets pose new challenges of visualization and interpretation. Here, we present a new kind of digital resource that encompasses almost 400 ganglion cells from a single patch of mouse retina. An online "museum" provides a 3D interactive view of each cell's anatomy, as well as graphs of its visual responses. The resource reveals two aspects of the retina's inner plexiform layer: an arbor segregation principle governing structure along the light axis and a density conservation principle governing structure in the tangential plane. Structure is related to visual function; ganglion cells with arbors near the layer of ganglion cell somas are more sustained in their visual responses on average. Our methods are potentially applicable to dense maps of neuronal anatomy and physiology in other parts of the nervous system.

Hemodynamic effects of continuous intravenous injection and bolus plus continuous intravenous injection of oxytocin in cesarean section.

BACKGROUND: Oxytocin may cause adverse cardiovascular effects, including tachycardia and hypotension, whereas the optimal dose of oxytocin at elective cesarean section is unclear. To determine the lowest effective dose of oxytocin, we studied the hemodynamic effects of three doses during spinal anesthesia for elective single cesarean delivery. METHODS: Sixty women received oxytocin by continuous (0.5 IU/min) or bolus-continuous (2 or 5 IU prior to 0.25 IU/min continuous intravenous injection) intravenous injection after clamping of the umbilical cord. We compared changes in heart rate (HR), mean arterial pressure (MAP) and estimated blood loss (EBL). Uterine tone (UT) was assessed by palpation on a linear analog scale (LAS) at 5, 10, 15, 20 and 25 minutes after the oxytocin injection. In addition, oxytocin-related side-effects such as nausea and vomiting were recorded. RESULTS: Marked hemodynamic changes such as HR and MAP occurred in the bolus-continuous groups but not in the continuous groups. Although we were not able to observe a variation of EBL in each group, the UT significantly increased in the bolus-continuous groups when compared with that the continuous groups. In addition, the hemodynamic changes such as HR and MAP were lower in the two IU bolus-continuous group than those in the five IU group. CONCLUSIONS: Although bolus-continuous injection of oxytocin resulted in more hemodynamic changes than continuous injection, bolus-continuous injection had a greater effect on uterine contraction. Furthermore, two IU bolus-continuous injection showed lower hemodynamic changes than in the five IU bolus-continuous injection.