Automated Bar Test for Measuring Catalepsy in Rats

A bar test measuring cataleptic response by recording and logging 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. The data is logged to a .csv file on an SD card. Intensity of catalepsy is measured as the length of time the rodent maintains this abnormal posture. Total price for all components is under $65.00 .

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 beam-break sensors which are attached directly above the bar. The bar can be moved vertically to adjust the height appropriate for the animal’s size. The timer starts once the rat’s forepaws are resting on the bar. When the rat descends from this posture, the break-beam sensors cause the timer to stop and the time is shown on an LCD display. The data is logged to a .csv file on an SD card. A push button saves the elapsed time into the logging module. The addition of data logging allows the researcher more potential for performing the behavioural measure without additional help.


Arduino code for operating circuitry, counting, and data acquisition

ino - 3.33 kB - 03/18/2020 at 18:53



3D model of bar test apparatus

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


View all 14 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
    Circuit Assembly

    Assemble the circuit following the circuit schematic seen in the images.

  • 3
    Assemble Bar

    Place bar through apparatus and attach nuts so as to "sandwich" the walls between the nuts. Heat shrink or electrical tape can be placed on bar to make it more comfortable for the rat. Attach sensors to inside nuts and face them toward each other. 

View all 5 instructions

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