| The following are NOT included in the
NeuroPDA or NeuroCCD Systems, but are necessary.
Microscope
In general, large numerical
apertures should be used to maximize light intensity. However, when the
signals of interest come from multiple focal planes, a smaller
numerical aperture may be required. The interface between the
microscope and all three cameras is a C-mount connector.
Microscope Light Source
In most cases the brighter the
light source the better. Both cameras are excellent at detecting small
changes on a large resting background. For absorption and population
fluorescence signals (where the light levels are high) a
tungsten-halogen source is often used. The microscope tungsten-halogen
lamp housing will often be satisfactory. However, the DC power supply
supplied by the microscope manufacturer may not be optimal and a
well-stabilized DC supply may be essential. For single cell
fluorescence (where the light levels are low) we recommend an arc lamp.
Opti-Quip, Inc,
(Highland Mills, NY 10930, 845-928-2254) provides 150 watt power
supply, lamp housings, and xenon arc lamps with noise that is in the
range of 1 part in 104. We found that the 150 watt bulb yielded 2-3
times more light than a tungsten filament bulb (over the range 475-565
nm) . Another supplier of Xenon arc lamps and power supplies, highly
recommended by one of our customers, is Cairn Research Ltd (Graveney Road,
Faversham, Faversham, Kent, ME13 8UP, U.K. tel: +44(0)1795 590140).
Shutter
A shutter which can be driven
by a 5-volt pulse should be available; shutter opens at 5 volts, closes
at 0 volts. In addition to limiting the amount of photo-toxicity, the
use of a shutter is essential for some frequently used features of the
software. We use shutter drivers and shutters from Vincent
Associates. Choose a shutter
opening that is larger than the diameter of the incident light beam. We
use a VS35S1ZM0R1-with heat sink shutter (designed to withstand high
intensity light and high temperatures) and a VMMD1 Shutter driver. We mount the shutter independently of the microscope
so that its vibration does not affect the recording (see photographs).
Stimulator
The software generates a
signal to the stimulator with a rising edge to 5 volts.
Splitters
For recording emission from 2
wavelengths simultaneously we have used and are supporting the Optical Insights, LLC
Dual-View splitter. A similar solution for doing emission ratio
imaging, the OptoSplit-II is offered by Cairn Research. With
these optical devices, each of the two images created by the splitter
is recorded simultaneously on half of the camera chip. When using a low
spacial resolution camera (e.g. NeuroCCD-SMQ) for recording very fast
transients, a better solution is to use a dichroic mirror as a beam
splitter and record simultaneously with two cameras.
Filters
The specific filters needed
for fluorescence measurements - excitation, emission and dichroic
mirrors - are dependent on the dyes used for the measurements. We
therefore include filters only with Macroscope II. Excitation filters
could be obtained from Chroma Technology Corp
. For emission, we find Schott Glass filters,
very good.
Camera Stands
Users who are not using a
microscope, need a stabilized optical arrangement to align the camera,
via a Macroscope or other lens, to look at the preparation. We have
helped several laboratories to put together such a stand, using
components from Linos . A list of
parts is available from us.
Vibration-Isolation
Optical recordings are very
sensitive to vibration. Most disruption is caused by vibrations in the
horizontal plane. A vibration isolation system, air table or table
supported by inner tubes is required. In situations where the
vibrational noise is not severe, a platform made from an optical
tabletop mounted on airfilled rubber tubes (obtained from
Newport: isolator, air cushion, #5274) is adequate. For more severe
vibration problems, Minus K Technology sells vibration
isolation tables with very low resonant frequencies.
Secondary Camera (for
NeuroPDA)
Because of the relatively low
spatial resolution of the NeuroPDA system, it is useful to relate the
optical signals to the preparation by obtaining a higher resolution
image. A high resolution camera (placed either in the usual position of
the array or a second view port) can be used to produce a TIFF or a BMP
file of the image of the preparation. The NeuroPlex software can import
these files and overlay the images with the pseudo-colored optical
data. A Dage-MTI CCD-300-RC (CCD Camera with RC300 Control) (Michigan
City, IN) with a 3045 Integral Technologies FlashBus MV Pro Frame
Grabber from I-Cube (Crofton, MD) has been successfully used for this
function.
Computer Monitor
We strongly recommend
purchasing a high resolution monitor (1600x1280 or greater) because it
is helpful to be able to visualize as much data as possible, and the
software display is designed for a very high resolution monitor. For
those who would like a NeuroPlex display larger than that provided by a
1600x1280 21 inch monitor, two monitors can be used simultaneously A
video card that supports two monitors is the Matrox, G200MULTI-MONITOR
(DUAL); part number G2/DUALP-PL (for PCI slot).(contact Brian Salzberg and AnaLia Obaid).
Room Lighting
The outputs of ordinary room
lights often introduce 60 or 120 cycles into the optical recordings. DC
powered lights should be available for experiments.
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