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SR-LAB startle response system
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The world’s most widely used startle response system.

SR-LAB™ startle response system is your best choice for startle reflex testing. The system’s design ensures accurate results for all paradigms. You will not be limited by the software to any specific paradigms, either—it supports any paradigm while ensuring your data is saved in a single-file for easy retrieval and export.

Test up to 16 animals at one time in SDI’s unique tubular enclosures which eliminate restraint stress and keep the animal in place to gather the most reliable data.

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  • Trust the most widely used startle response system on the market
  • Easily test virtually any paradigm using one software program
  • Ensure accurate readings with the accelerometer designed to accommodate rapid force changes
  • Expand testing up to 16 stations
  • Test animals of varying sizes
  • Verify data using the View Wave™ post session data analysis tool


The SR-LAB startle response system is the world’s most widely used startle reflex behavioral research system and the most successful for measuring startle habituation, pre-pulse inhibition (PPI) and Fear Potentiated Startle (FPS)

Execute any and all startle reflex testing paradigm using the SR-LAB Software and specialized additional kits—and ensure accuracy using SR-LAB’s proprietary accelerometer which accommodates the rapid force changes in startle testing.

The only system of its kind that expands to 16 test stations, your SR-LAB™ will test a large number of animals at any given time. It will also test animals of varying sizes—from the smallest mouse to the largest rat using one of five sizes of easily changeable animal enclosures.

Highlights of the SR-LAB™ Startle Response System include:

Easily Test the Most Prevalent Test Paradigms

The basic SR-LAB System will test the Startle Habituation and Pre-Pulse Inhibition paradigms with no additional kits required.  To test the Fear Potentiated Startle paradigm, simply add on the SR-LAB Potentiated Startle Kit which includes the SDI Shocker (a proprietary design that keeps the animal from determining any patterns), a shock grid, and a cue light. Support any of these paradigms with the SR-LAB software, with no additional software required.

One Software Program for All Paradigms

With the SR-LAB software, you can develop and execute any startle reflex testing paradigm.  Other systems utilize different software for each paradigm which has two drawbacks: One—you will spend more money, and two—you have no flexibility in designing your own paradigms, and instead are limited to the paradigms offered by the manufacturer.

Be assured all trials are executed without missing any trials using SR-LAB’s concept of a Session containing Trials (discrete tests). Each session will run the animals through all the trials, and save all trial data for later analysis.

Other highlights of SR-LAB™’s software include:

  • Construct Trials Definitions with No Programming Required

    Define your trials to meet your specific needs by selecting commands from a wide range within a predefined menu and then entering your start/stop times. 

  • Point and Click to Set Session Level Parameters

    Set your session level parameters, construct trial lists, and set up Inter-Trial Intervals using SR-LAB’s simple point-and-click interface.

    Your session parameters can include number of samples, sample rate, background noise level, and repetitions. You can also define and edit sessions with the click of a mouse by inserting or removing Trials. In addition, edit or rename your sessions any time with ease.

    The ability to automatically randomize durations of for Inter Trial Intervals assures that the animal will not discern a pattern that would skew results.

  • At-a-Glance Test Monitoring

    Monitor your test process at a glance by viewing response waveforms. Unlike other systems, the waveform visual gives you quick assurance that the calculated numbers are accurate.

  • Verify Data with Ease Using “View Wave™”

    Verify all of your startle response data with the View Wave™ post session data analysis tool. View Wave™” helps you verify data accuracy by working off scoring parameters set by you. For each response, you can review the complete waveform to verify your numeric data.  Scoring parameter  you can set include Baseline, Onset Window Start, End Analysis and Onset Criterion.  View Wave™ also assures your calculated values are correct by allowing you to see, export, and use your raw data values.

  • Make Data Analysis Easy with Point-and-Click Consolidation

    Combine all of your data with a quick point-and-click in into ASCII file format or another statistical program. SR-LAB Software will preview the data for you, then take it from there. Once you’ve combined your data, you can export to Microsoft® Excel at any time. 

  • Eliminate Concerns about Inaccurate Readings

    SR-LAB’s accelerometer is a key factor in the accuracy the system provides.  The sensor reacts very quickly to sudden force changes—assuring you get an accurate reading for the smallest mouse to the largest rat.  The accuracy provided by the sensor is aided by a complimentary enclosure design, which tightly couples the enclosure with the sensor.  Other systems use Load Cells which do not react as well to sudden force changes and also have limited ranges, requiring you to change load cells as animal weights change.

  • Avoid Stress-Induced Results

    The SR-LAB’s tubular enclosures are designed to allow the animals to turn around freely without constraint—thus avoiding restraint stress that can alter results. At the same time, the tubular design keeps animals over the sensor for reliable results. Your subjects will be monitored using an ultra-stable, hermetically sealed motion sensor that records a wide range of startle responses. Enclosures are designed with clear acrylic for easy cleaning and are available in five different sizes.

System components include:

  • Test cabinet in composite (ABS) or laboratory grade laminate (Prime)
  • Animal enclosure in choice of standard sizes
  • Power supply
  • Input and Output cables
  • Animal enclosure base
  • Software and User Manual
  • Software utilities for data analysis


  • ABS Isolation Cabinet - 15” (W)  x 14” (D) x 18” (H)
  • Prime Isolation Cabinet - 16" (W) x 15" (D) x 23" (H)
  • Control Box - 16” (W) x 14” (D) x 5.75” (H)
  • Small Animal Enclosure - 3.5” (L) x 1.1” (ID)
  • Small/Medium Animal Enclosure - 5” (L) x 1.5” (ID)
  • Medium Animal Enclosure -  6” (L) x 2.25” (ID)
  • Large Animal Enclosure - 8” (L) x 3.5” (ID)
  • X-Large Animal Enclosure-  10" (L) x 5" (ID)


  • 24 lbs. (ABS Isolation Cabinet), 51 lbs. (Prime Isolation Cabinet), 6 lbs. (Control Box)

Material Composition

  • ABS Isolation Cabinet: ABS plastic, Prime Isolation Cabinet: Laminate
  • Control Box: Aluminum, Animal Enclosure: Acrylic

Maximum # Stations

  • 16 stations per computer

Standard Cable Lengths

  • 8 ft.

Stimuli Options

  • Tones, noise bursts, background noise, lights, air puffs, foot shocks and user-defined stimuli

Color Options

  • White


Use the Startle Paradigm You Need without Constraint

If the paradigms you need are not included with SR-LAB’s basic kit, add-on kits are available, requiring no additional software or constraints. Add-on kits offered include:

Pure Tone Kit

The Pure Tone Kit supplies up to three specific frequencies of sound and is generally used as a pre-pulse stimulus.  This kit is also used for gap detection startle reflex testing.  You control the frequency, amplitude and duration via the SR-LAB software.

PPI LED Light Kit

An add-on light to the animal enclosure is used as a Pre-Pulse stimulus to provide cross-modal startle reflex testing.  On and off times are controlled from the SR-LAB software.

Tactile Kit

The Tactile Kit provides an air puff stimulus, which is generally used as a kinder, gentler alternative to shock. 

Relay Chassis

The Relay Chassis gives you maximum flexibility in your startle testing.
It contains four relays to control the On/Off of external devices (which are not supplied by San Diego Instruments).  The SR-LAB Software controls the Relay Chassis.

High Intensity Light Kit

The kit supplies an immense amount of bright light within the test station, which brings on anxiety in the animal.  The LED lights give off no heat, which can affect the animal. This kit is used for anxiety potentiated startle testing.

Easy Calibration Sets a Standard Baseline Response

The baseline response of each of your test stations will be set to the same level prior to testing using the Standardization Unit, which attaches to the top of the animal enclosure and places a repeating fixed force on the sensor.  Adjust the response level to the guideline numbers in the user’s manual by turning the Response Adjust dial on the side of the test station.  After setting one test station, all you need to do is move the Standardization Unit to the next station and repeat.  This assures that results data from multiple tests stations can be compared and your resulting analysis is reliable.

Measurement of Startle Response, Prepulse Inhibition and Habituation
Geyer MA, Swerdlow NR.

5-HT1A Receptor Knockout, but not 5-HT1B Receptor Knockout Mice, Show Reduced Startle Reactivity and Footshock-induced Sensitization, as Measured with the Acoustic Startle Response
Anneloes Dirks, Tommy Pattija, J. Adriaan Bouwknechta, Tatjana T. Westphala, Theo H. Hijzena, Lucianne Groeninka, Jan van der Gugtena, Ronald S. Oostingb, René Henc, Mark A. Geyerd and Berend Oliviera

Startle Responses, Heart Rate, and Temperature in 5-HT1B Receptor Knockout Mice
Bouwknecht, J Adriaan; Hijzen, Theo H.; van der Gugten, Jan; Dirks, Anneloes; A. Maes, Robert A.; Hen, Rene; Geyer, Mark A.; Olivier, Berend

The Effects of Perinatal AZT Exposure on the Acoustic Startle Response in Adult Rats
Susan M. Melnicka, Jeremy Weedonb and Diana L. Dow-Edwards

GABA-A and 5-HT1A receptor agonists block expression of fear-potentiated startle in mice
Risbrough, Victoria B.; Brodkin, Jesse D.; Geyer, Mark A.

Metabotropic Glutamate Subtype 5 Receptors Modulate Locomotor Activity and Sensorimotor Gating in Rodents
Kinney GG, Burno M, Campbell UC, Hernandez LM, Rodriguez D, Bristow LJ, Conn PJ.


View All Reference Articles


Q: Why is an empty chamber in the SR-LAB giving us a reading?

A: Because, as with any system, there is small amount of electrical and mechanical noise in the system. Empty chamber values should be small (<10). This noise is accounted for in the system calibration so the net test results aren’t affected by the ambient noise in the chamber. Contact SDI if these values are large. ALSO SEE NEXT FAQ.

Q: I calibrate my SR chambers but still get widely variable results, why?

A: If the variability is among the chambers when you calibrate, make sure that your chambers are on a stable, flat surface - seismic isolation of chambers is important. If a rigid counter cannot be used, consider mounting chambers on concrete blocks. If the variability is low in calibration, but is seen in animal data, ask SDI for materials dealing with “Minimizing Variability in Startle Testing”.

Q: Why am I not getting any shock with my SR-LAB?

A: The ‘device number’ may not be set properly in the “Configuration” menu. It should be set to “2” in the Windows-based system. Check that the power supply is connected to the rear of the Control Box. Verify other connections. Check for a bad fuse. Disconnect the power supply, remove the top of the shocker unit. Check glass fuse - right rear on the shocker board. Replace with same rate fuse.

Q: Why am I not getting any readings from my SR-LAB?

A: The BNC cables may be reversed at the IN/OUT connection. Change them on the control box. Verify that the units have power (check that light and fan goes on). Check all connections per the manual.

Q: Why am I not getting a startle response from my mice?

A: Your mouse may be of a strain that loses hearing as they age. Check to make sure they can hear. Many researchers find that mice show a better startle response to tactile rather than acoustic startle stimuli.

Q: What is the max number of test stations that can be used with SR-LAB?

A: Sixteen stations.

Q: What is the difference between habituation, pre-pulse inhibition and potentiated startle testing.

A: Refer to Geyer, M.A. and Swerdlow, N. R Measurement of Startle Response, Prepulse Inhibition, and Habituation in Current Protocols in Neuroscience (1998) 8.7.1-8.7.15 .

Q: Why do I need a Standardization Unit? 

A: The Standardization Unit provides a constant input to the SR-LAB software. This allows each chamber to be adjusted to remove any sensitivity variances. The Standardization unit establishes the reliability of the test stations (similar sensitivity among stations and over time), but reports relative values in millivolts.

Q: Can you explain how to set up test sessions?

A: First, construct your Trials using the commands from the software menu. Then, construct a Session Definition to control the Background level, the Recording granularity, the Inter-Trial Intervals and the number of repetitions. Within the Session Definition, insert the Trial names you want to run. We strongly recommend you refer to Geyer, M.A. and Swerdlow, N. R Measurement of Startle Response, Prepulse Inhibition, and Habituation in Current Protocols in Neuroscience (1998) 8.7.1-8.7.15 .

Q: Do I need an additional isolation cabinet around the SR-LAB chamber for sound attenuation?

A: No, except in unusual circumstances.

Q: Why doesn’t my trial work as expected? Why does a stimulus unit stay on after completion of a trial?

A: Any commands that terminate after the "Record Window" are ignored. Extend the "Record Window" or move the "Record Window" in the Trial. 

Example Trial Definition (assume a 200msec recording window): 
0msec Background
0msec Wait 50
50msec Analog 600
50msec Record
50msec Wait 300
350msec Background
end of Trial

In the example provided above, the Analog signal will stay on because the Background command at 350msec won’t be processed due to the fact that the Record Window went from 50msec to 250msec. To correct this problem, in the Trial Definition, you would change the Wait 300 Command to Wait 200.


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