Microscopes for neurophysiology

Bioso£t's neurophysiology simulation program, Neurosim, has now been released as a Windows package. The new version has been completely rewritten to take advantage of the Windows interface. The user first selects the experimental and neurophysiological parameters desired for a particular simulation, and then runs an experiment. The computer generates a graphical display similar to that of an oscilloscope in a genuine electrophysiological experiment. The parameters can then be varied to explore the effects of differing conditions. Combinations of parameters can be saved and automatically recalled on subsequent occasions. There are three main modules in the package: H H simulates the Hodgkin-Huxley model of nerve impulses; Network allows the user to construct arbitrary circuits of neurons interconnected by non-spiking or spiking chemical synapses, or electrical synapses; Patch simulates the kinetic properties of single ion channels-a two-state open/shut channel, a three-state agonist-activated channel and a three-state shut, open or blocked channel. The new I X Series of inverted microscopes from O l y m p u s is the result of extensive consultation and a fresh approach, and provides improved optics, ergonomic and stable design, and applications flexibility for celt culture and bio-ogical research. A central development is the new UIS infinity-corrected optical system, which gives a unique field of view. The observation area is 2 1 % greater than that of conventional microscopes. The shape of the IX Series is based on a rigid Y-frame. This, together with the stage support design, provides improved stability and freedom from vibration. At high magnification and for micromaniptilation techniques, or for patch clamping, this additional rigidity is a major benefit. For research use, the system allows adaptation for laser applications. Laser attachments can be used for optical tweezing, to irradiate parts of a specimen with specific wavelengths, or selectively to cut out cells or parts of ceils from a specimen. Spherical and chromatic aberrations can be introduced when viewing specimens through glass or plastic containers. These can be adjusted for in.the IX Series with a two-stage approach-three top lenses provide a large-scale adjustment for 0.5 ram, 1.1-2 m m and 2 m m thicknesses, for a choice of materials; fine adjustment is then carried out by exact collar correction rings which cover a-+0.5 m m range. The microscopes can be adapted for electro-physiological experiments with biological warm plates, a stage plate for mounting miniature micromanipulators and a cross-movement stage with short left-hand drive controls. …