We are trying to make NOR for adult Wistar rats in our lab. The literature varies on the dimensions that should be used. I wanted to know what can work best for this. any kind of help is appreciated.
Hii Gouri Jadhav
We have been using Square box of 40cm x 40cm for Mouse dimensions and Square box of 100cm x 100cm for Rat dimensions. It works quite well for both Open Field Test and NORT. You should preferably color the box in black paint as you'd be using for wistar rats analysis.
Hope it helps.
Thanks
Hello Gouri Jadhav ,
This is really a confusing thing for a laboratory who is planning to start NORT, which is very common and preferable test for episodic memory. The reason is being different laboratory has their own standards for selection of object. However, the main three thing which we should keep in mind while selecting a object for NORT in rodent, is colour, texture, shape/size and smell of the paint (provided if you use your own object painted in your lab). The quick solution is buy objects for NORT from companies like TSE, Stoelting they sell their object for rat/ mouse.
However, you can actually neglect the colour of the object as rodents see only black and white and in some article few species of rodent are proposed to have UV ray in their visibility range. And when a rodent explore object they mainly do it by tactile sensation either using their fore-legs or vibrissae/ whisker. Therefore, texture plays a major role here. The thumb rule is that as big object is it is more noticeable and preferred by rodent. But, the catch is that it should not be so big that it will induce fear in animals (observed by feaces/ urination during exploration). Like cap of a bottle can be neglected but 50ml normal saline bottle can be noticeable. And theoretically we can not use objects already familiar with the animals, viz. objects used in breeding facility or may be available in nature which is gazing field of the ancestors of the lab mice/ rat.
You can go through the articles in JOVE. They sometimes gives dimensions about the objects.
So, for me the best solution of these problems is to calculate Interest Index (II) using few available objects randomly selected in a batch of control animals. The objects eliciting higher II will be good for use. You can look at the supplementary copy of one of our manuscript in preprint server for detailed understanding regarding the same. Though it is also available in my RG account.
Preprint Cognitive dysfunction and anxiety resulted from synaptic dow...
Hope this will help you a bit.
With best regards,
Avishek