Automated Catalepsy Bar Test for Rats

A bar test measuring cataleptic response by recording the time elapsed before the rodent releases from the bar.

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The automated catalepsy bar test is an open source, 3D printed test apparatus used to make catalepsy measurements in rats more standardized and accurate. The bar test entails positioning the rodent’s front legs to be resting on the bar in which the timer will start. When the animal descends from this posture, the beam break causes the timer to stop. Intensity of catalepsy is measured as the length of time the rodent maintains this abnormal posture. Total price for all components is under $50.00 .

Catalepsy is a state of behavioural immobility characterized by muscular rigidity and failure to correct an imposed posture for a prolonged period of time. Measuring catalepsy is of interest to our lab due to its similarity to behaviours seen in human disorders such as schizophrenia and Parkinson’s disease. This test is also used as a part of the tetrad for the pharmacological effects of cannabinoids, as well some of the extrapyramidal side effects of antipsychotic drugs.

The test apparatus includes an automated timer connected to a beam break that is attached directly above the bar. The bar can be moved vertically to adjust the height appropriate for the animal’s size. Upon breaking the beam, the timer begins to count in 0.1 second increments. When the beam realigns, the timer freezes; it cannot be re-broken for a period of 5 seconds to ensure the beam doesn't reset while the rat is removed. 


Counter program

ino - 680.00 bytes - 07/11/2019 at 14:59



3D model of bar test apparatus

Standard Tesselated Geometry - 17.46 kB - 07/11/2019 at 14:58


View all 10 components

  • 1
    3D print housing

    The housing should be printed upright. No structural supports should be needed. The printer filament used for this design was PLA; however, any filament should work equally well. If the 3D printer being used is too small to print the housing in one piece, the housing can be sliced, printed in several pieces, and epoxied together. 

  • 2
    Assemble and solder 7-segment display
  • 3
    Connect 7-segment display to Adafruit Metro Mini

    Connect pin 1 (+) to 3V, pin 2 (-) to ground, pin 3 (D) to A4, and pin 4 (C) to A5. 

View all 5 instructions

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