All KNOSYS components are simple, trouble free, rugged and easily modifiable by the user. Only widely available, easily replaceable parts are used and all components, including electrical connections are accessible to the user. Chambers are easily removed and disassembled for cleaning.
The Operant Chamber
The operant chamber is constructed of 3/8 inch (9 mm) Plexiglas and is attached to the board containing the odor generator. The removable front panel of the chamber contains a glass odor sampling tube, two stainless steel water delivery tubes, a signal light, and a buzzer. Snout insertions into the odor sampling tube are detected by an infrared photocell emitter and detector; lick responses on the water delivery tube are detected by a ‘lickometer’ circuit. Modifications are available for studies using electrophysiological recordings that may require a larger sampling port and non-electrical contact detectors. Chambers are available for rats and for mice. The front panel of the chamber can also be modified to mount on the animal’s home cage or other enclosure.
Software Routines
Software provided with the olfactometer includes a Utility program, initial training program (BEGIN) and programs for detection and discrimination training allowing the use of 2 or more stimuli. The Utility program contains routines for calibrating reinforcement delivery and checking all interface functions. The initial training and discrimination programs are based on a typical go, no-go discrete trials training and test procedure in which, on any one trial, either a positive (S+) or negative (S-) stimulus is presented and the subject is rewarded for responding in the presence of the positive stimulus (see the 2005 Slotnick and Restrepo paper). These programs are those used in virtually all published accounts employing the Knosys olfactometer. While the programs allow a wide variety of stimulus presentation parameters, they provide a set of default values, ones that are most widely used in published accounts. BBCBASIC, an advanced BASIC language, is actively supported in a number of on-line sites and is compatible with virtually all MS operating systems. Timing accuracy is to the nearest centi-second (10 msec). The BASIC language is easily mastered (for those with an interest in modifying or creating programs) yet sufficiently sophisticated to allow for complex functions. Knosys provides a BBCBASIC license to the user.
Power Supply
Any regulated and adjustable 24 vdc power supply rated at least 1.5 amps can be used to power the system. The Knosys power supply is a high quality, regulated, and metered unit rated at 3 amps and can power up to 5 olfactometers.
Response and Water Delivery Tubes
Operant chambers contain two water delivery tubes: one (the IN tube) is located within the odor sampling port and a second (the OUT tube) located adjacent to the odor sampling port. IN tube training is highly efficient and most often used. However, OUT tube training allows the operator to measure odor sampling time on each trial. Separate programs are provided for IN and OUT tube training and testing.
Water delivery for correct responding is provided by a gravity-fed water reservoir whose output is controlled by a normally closed solenoid. Reliable delivery of volumes of 2 – 4 uL (for mice) or 30 – 50 uL (for rats) is achieved using in-line flow restrictors and appropriate timing of valve operation.
Odor Saturator Bottles
The PVC odor saturator bottles are disposable and because these and their connecting tubing will become contaminated with the odorant used, they should be changed with clean components when a new odorant is used in a channel. Thus, we recommend the purchase of additional odor sampling bottles and several rolls of C-flex tubing (tubing used by the odor control pinch valves). C-flex tubing can be purchased from us or from Cole Parmer. The disposable odor saturator bottles are provided with caps drilled to accommodate input and output tubes. A special 5.5 mm diameter drill/punch tube is available for users who prefer to drill holes in bottle caps themselves. The drill tube must be used with a high speed drill press.
KNOSYS software programs are NOT multi tasking and we advocate a dedicated computer and interface for each behavior test system.
KNOSYS
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