Small additional comment: You have to define your conditions in detail. For example you will consider that the animal has entered a square if it has two paws in the square. If you are going to measure activity manually as suggested above, make sure to record the test (video). Then have two independent researchers, blind to the experimental conditions,  watch the video and record their findings. I assume you will be using stopwatches. Since the animals are usually quite fast, the person watching the video may need to have an assistant to record what they say on a chart. Then check the variance between the two researchers statistically. If the findings of the two researchers agree, you can take the average and trust your findings. If the two findings are not in agreement, then you should have one or two more researchers watch the videos and record their findings again. If you want to publish your research findings in a good journal, please make sure to address all these issues properly. Since many labs are using automated equipment, you have to convince the reviewers that your method is reliable. On the other hand, I truly admire your plan to do this test manually even if the financial conditions do not allow you to buy expensive equipment. Good luck.

Rafael

One technique is to divide the floor of the cage in squares and then count the squares occupied by the animal in blocks of time. I have done that with good outcome.

Menna

Hi, Rafael.

As Luiz Menna-Barreto said, you can divide the floor of the cage in quadrants, and quantify also the number of crosses of the quadrants lines. It will give you a good estimate of the locomotor activity of the animal.

Good luck!

Hi Menna and José,

Thank you for the answers! Do you know someway to divide the cage in blocks in the video recorded? It's because we've already conducted the test and need a way to edit the videos to divide the cage in zones...

Hi Rafael.   so what you need to do is insert your video into mso ppt blank slide, apply a grid as a foreground ( you can make grid lines as many or as little as you want , the color and the thickness you want )  play the video, there you have it,    best wishes with your tests.

Ghanim

All the advices are right. now I also did the same way and got very good result. Please check the publication.

All the best for your experiment.

Sumana

Hi, Ghanim, thank you very much for the answer! I will try this! Thanks Sumana!

In an undergraduate practical class, I let students trace the mouse movement  on a paper sheet , by pencil, on which the open field floor was drawn. You can easily count number of line clossings on the sheet. Also you can measure the distance they traveled  by a map measure. It is very economic experiment!!

Thank you Yasuhiko!

The division of the floor into squares is a useful method to measure locomotor activity without automated systems as infrared photocells or videotracking softwares. In addition to the number of squares crossed by the animal, you can also score:

a) the total time spent in the central zone and in the peripheral zone (if you have a 3 x 3 division of the floor, the central zone will be the central square, while all the rest will be periphery; if you have a 4 x 4 division, the central zone will be composed by a 2 x 2 zone);

b) latency to enter the central zone (point of release of the mouse should be one of the four corners, randomized, and the animal should be released with its head facing the wall);

c) number of entries in the central zone;

d) latency to first rearing (vertical movement);

e) number of rearings.

Even with a "low-cost"  experimental setting you can  have anyway several useful variables to evaluate locomotor activity and anxiety in the open-field test.

 Thanks Raffaele!

All of the above answers are very good. I just want to add that you can measure number of liking/wahing/ scratching  (grooming) or time spent in grooming manually or later on seeing the video recording. 

Thanks Arun!

Small additional comment: You have to define your conditions in detail. For example you will consider that the animal has entered a square if it has two paws in the square. If you are going to measure activity manually as suggested above, make sure to record the test (video). Then have two independent researchers, blind to the experimental conditions,  watch the video and record their findings. I assume you will be using stopwatches. Since the animals are usually quite fast, the person watching the video may need to have an assistant to record what they say on a chart. Then check the variance between the two researchers statistically. If the findings of the two researchers agree, you can take the average and trust your findings. If the two findings are not in agreement, then you should have one or two more researchers watch the videos and record their findings again. If you want to publish your research findings in a good journal, please make sure to address all these issues properly. Since many labs are using automated equipment, you have to convince the reviewers that your method is reliable. On the other hand, I truly admire your plan to do this test manually even if the financial conditions do not allow you to buy expensive equipment. Good luck.

As Sakire said, it is fundamental to define what you are going to consider as a "square crossing". Two main criteria can be used: 1) entering a square with the two forepaws; 2) entering with all four paws. You can choose, but personally I would use the four paw entrance criterion.

Thank you, Sakire, Daniel and Raffaele!

I have tested mice manually for years. E.g.:

In the practical class for undergraduates, I let students trace mouse open field movement on a paper sheet by a pencil. Then, as others said, students may count number of crossing lines drawn on the floor by the mouse. I also ask them to measure the distance the mouse ambulates by a map measure.

https://www.amazon.com/Alvin-Double-Readout-Plan-Measure/dp/B000O9WX8O/ref=sr_1_4?ie=UTF8&qid=1542379968&sr=8-4&keywords=map+measure