LEDs: Convenient, inexpensive sources for visual experimentation

Origin of Transient and Sustained Responses in Ganglion Cells of the Retina

“…C lampex8 (PC lamp8; Axon instruments) was used to control the voltage command outputs, acquire data, and trigger the light stimulus. The light source was a Stanley red light-emitting diode (L ED), which emitted ϳ10 4 photons/m 2 per second at 620 nm (Nygaard and Frumkes, 1982). The currents and voltages shown are raw data, and electrode junctional potentials and access resistances were not corrected.…”

Stratification of alpha ganglion cells and ON/OFF directionally selective ganglion cells in the rabbit retina

“…A diffuse light stimulus was generated by a green light-emitting diode (LED) (Nygaard & Frumkes, 1982), which was positioned near the recording chamber and driven sinusoidally by an Axon Digidata 1200 with PClamp software. Sharp intracellular electrodes (200-300 MΩ) were pulled on a Brown-Flaming P-87 horizontal electrode puller (Sutter Instrument, Inc., Novato, CA) and filled with 4% Lucifer Yellow (Molecular Probes, Eugene, OR) in 0.05 mM phosphate buffer (PB) and back filled with 3 M lithium chloride.…”

A portable, solid-state anomaloscope

“…Moreover, since it has no moving parts, it is substantially less fragile and less subject to misalignment or calibration errors. The device on which such a design is based is the light-emitting diode, or LED (see review by Nygaard & Frumkes, 1982). LEOs emit narrow-bandwidth illumination, comparable to that used in filter anomaloscopes, at various points in the visible spectrum as a function of their chemical composition.…”