Operant Algesiometers

Operant Conflict-Avoidance System (OCS)

The OCS provides an operant method of pain testing with rodents that complements reflexive methods by addressing cognitive and motivational processing.

This operant behavioral system consists of a 3-chambered red acrylic unit where chamber 1 contains an aversive bright light, chamber 2 is darker with a textured floor or heated/cooled floor as the stimulus (variable from innocuous to noxious), and chamber 3 is dark (safe haven). Rodents are given the opportunity to escape the bright light by crossing chamber 2 to the “rewarding” dark chamber. Dependent measures are related to the perceived or actual noxious input evoked by the stimulus; exit time from chamber 1 (emphasizing the cognitive components of pain) and duration in chamber 2 (emphasizing the sensory component of pain).

Use three interchangeable stimuli to test multiple pain models with one device

  • Mechanical
  • Heat
  • Cold

Simple adaptations allow a single OCS to be used for both rats and mice.



Features and Benefits

  • Easy to disassemble/assemble for transport and cleaning
  • Constructed from durable acrylic
  • Compact enough to allow multiple units in one
  • Testing is faster than other operant methods (most MCS tests are completed in less than 1 minute)
  • Complements reflexive methods
  • Adaptable to other stimuli beyond mechanical and light lab
  • Animal training is fast and simple
  • Red color enables researcher observation while rats perceive it as black/dark

Bright light (1) serves as the aversive stimulus for test initiation. Animals can cross an array of nociceptive probes (2) to reach a preferred dark compartment (3)

Operant Algesiometer with numbered chambers by Coy Labs

Publication Utilizing the MCS

Lau, D., Harte, S.E., Marrow, T.J., Mata, M., Fink, D.J. (2012) Herpes Simplex Virus Ve Mediated Expression of Interleukin-10 Reduces Below-Level Central Neuropathic Pain After Spinal Cord Injury. Neurorehab Neural Repair: September 2012 vol. 26 no 7: 889-897


Dimensions 32.2  x 8.25  x 17.75 (inches)
Power Requirements 24 Watts
120v AC 60Hz*
Probe Height Increments 0.5,  1,  2,  3,  4,  5 mm
Accuracy of probe height above base +/- 0.5mm (across entire array)
Light Output (Avg.) 500-600  foot –candles
*optional transformer available for use with 220v, 50Hz
Primary Materials of Construction ·         Acrylic

·         Polycarbonate

·         Stainless Steel Probes on Aluminum support plate