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Certain periodic dot patterns (Marroquin patterns) generate a percept of dynamically oscillating circles, and analogous effects were explored by op artists in the 1960s. Here we show psychophysically that circles are perceived in these patterns only around specific points that are quantitatively predicted by a neural model of configural units hypothesized(More)
We present a technique for stimulating post-synaptic receptors with neurotransmitter locally at a single synapse and with a concentration profile that is comparable to endogenous stimulation. We modify the technique of iontophoresis to use a 0.1 microm electrode tip for local stimulation, and we combine it with fast capacitance compensation to achieve(More)
The need to capture the complexity of biological systems in a simpler formalism is the underlying impetus of biological sciences. Understanding the function of many biological complex systems, such as genetic networks or molecular signalling pathways, requires precise identification of the interactions between their individual components. A number of(More)
The interplay between activated G proteins and intracellular calcium ([Ca(2+)](i)) in the regulation of secretion was studied in the macrophage, coupling membrane capacitance with calcium-sensitive microfluorimetry. Intracellular elevation of either the nonhydrolyzable analogue of GTP, guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S), or [Ca(2+)](i)(More)
Secretion of lysosomes and related organelles is important for immune system function. High-resolution membrane capacitance techniques were used to track changes in membrane area in single phagocytes during opsonized polystyrene bead uptake and release. Secretagogue stimulation of cells preloaded with beads resulted in immediate vesicle discharge,(More)
How synapses change their strength in response to impinging neural activity is a fundamental issue for understanding how the brain molds its circuitry in response to behavioral experience. Although a growing number of studies reveal the involvement of postsynaptic changes contributing to synaptic plasticity in brain circuits, the involvement of presynaptic(More)
Calcium influx associated with the opening of N-methyl-D-aspartate (NMDA) receptor channels is the major signal triggering synaptic and developmental plasticity. Controlling the NMDA receptor function is therefore critical for many functions of the brain. We explored the mechanisms of synaptic activation of the NMDAR glycine site by endogenous coagonist(More)
Immunoglobulins IgA and IgG levels and Lysozyme-activity were examined in the vaginal fluid of 70 pregnant women and 30 non-pregnant women where microbiological examinations did not detect any pathological microorganisms. To confirm the local character of immune factors produced in the female genital tract, these factors were also examined in the sera. An(More)