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Freeze Monitor

Study cued and contextual fear conditioning using the system that provides unparalleled accuracy and ease of use.#

SDI’s Freeze Monitor allows you to run up to four independently-starting test stations from your computer using one USB port. Your tests will provide highly accurate data thanks to the tightly spaced 16×16 photobeam array design, along with the ability to pre-define your test sessions—eliminating run time errors.

Once testing is complete, access and export your freeze monitoring data from a single file, ensuring no tests go missing inadvertently.


  • Run up to four stations with independent start/stop from a single PC
  • Monitor subjects accurately with a 16×16 beam array
  • Ensure accuracy by running the same test definition used in a cued paradigm in a Context Box
  • Record all data in a single physical file in table format
  • Conversion from rats to mice is possible in less than five minutes
  • Freeze Detector Report reports number of episodes and duration of each episode


Freeze Monitor is a fully computerized system designed to study cued and contextual fear conditioning. The system’s tightly spaced 16×16 photobeam array monitors animal movement with exceptional accuracy. Beam spacing of just .75 inches ensures that activity of the smallest subjects is recorded.

During your freeze monitoring test, the software will record latency to movement after a “freezing” event. By connecting up to 4 freeze monitors to your computer via USB interface, the software sets up easily with no technical knowledge required.

The Freeze Monitor contains a sound cue, light cue and shocker unit with 8 distinct outputs. The shocker unit insures that the animal cannot discern a shock pattern providing accurate behavior. In addition, a hexagonal opaque drop in Context Box is used providing the same sound and light cues for Contextual Fear Conditioning.

Highlights of the Freeze Monitor Include:#

Connect Up to 4 Freeze Monitors Using a Standard USB Port Eliminate specialized interface cards and drivers requiring extensive technical knowledge to set up. The Freeze Monitor utilizes a standard USB to serial converter cable to connect the Freeze Monitors to your laptop or PC. SDI can provide a fully configure computer or laptop for a minimal price.

Freeze Monitor Software The Freeze Monitor software gives you more flexibility than ever. Define your complete study in advance in a single file by pre-assigning specific animals to specific test stations for each test session and assign a predefined test definition to each test session. The software will automatically record your session data and store it in the Study’s file keeping all data together. When you are ready, you’ll be able to display your data right on your computer monitor or choose to export it with one click to Microsoft® Excel or to a delimited file type(TAB, CSV, etc.).

Test Definitions The Test Definitions control the Light, Sound and Shock stimuli and the Latency durations for monitoring the subject. Each stimuli duration is controlled by the Test Definitions. The shock level is also set in the Test Definitions. Another key feature is the setting of the Inter-Test intervals either for fixed durations or random durations. The Test Definitions can be saved and reused in multiple studies assuring accuracy and eliminating redundant data entry saving you time.

Study Definition A study will contain multiple discrete test sessions using some number of subjects. You can define each of these test sessions in advance entering session parameters and assigning the Test Definition to the session. All this data is kept in a single file in table format. This approach assures accuracy of data and assures tight coupling of results data with the correct subject.

Session Run Each Session is selected from the Study definition and Subject Id’s, Dose Groups and Subject Variables are entered for each test station. You can choose the Start All option or the individual Start Option for each test station.

Reporting The Freeze Monitor software makes the table formatted results available for direct export to Microsoft® Excel or to a delimited file type (TAB, CSV, etc.). All data is identified by column headers. Storage of all data in a single file assures that no data is missing. The elimination of the need to aggregate multiple single files and possibly reformat them again assures accuracy of results and saves you significant time. In addition the data can be reported either by the Freeze Monitor software or the Freeze Detector. The Freeze Monitor software provides a report that follows the human observation method showing latencies to movement at periodic intervals. The Freeze Detector program provides you with a settable Freeze Episode duration parameter. Any immobility exceeding this parameter is considered a “freezing episode”. Number of “freezing episode” and duration of each “freezing episode” are reported. This dual reporting feature provides you with two different analyses of the software assuring accurate analysis.

Ensure Accuracy and Streamline Testing with Drop-In Context Box#

The uniquely-shaped hexagon Context Box drops inside the Freeze Monitor enclosure. The specialized plastic allows the photobeams to shine through to monitor the animal behavior, providing two key advantages: One, ensure accurate results by running the same test definition as with the cued test, and two, you will eliminate the need for a separate context test station.

System components

  • Acrylic test enclosure with integrated shocker, cue light and Sonalert acoustic stimulus unit, includes excreta pan
  • Stainless steel grid shock floor
  • All required cables and connectors
  • Freeze Monitor Context Enclosure (optional)
  • Isolation Cabinet (optional)


Outside Dimensions 14” (W) x 15” (D) x 12.5“ (H)

Inside Dimensions 10” (W) x 10” (D) x 7.5“ (H)

Weight 12 lbs.

Material Composition Acrylic

Maximum # Stations 4

Number of Photobeams Infrared photobeams in a 16 x 16 array

Photobeam Spacing 1/2″ in each direction

Certifications CE

Stimuli Options Sound, light, shock

Stainless Steel Grids 1/4″ grids spaced at 9/16″ for rats 1/8″ grids spaced at 5/16″ for mice

Context Enclosure Box 9 7/8″ x 9 7/8″ x 14” x 7 ” (Deep)