I tried looking in Allen brain atlas but to no avail. All the literature that I found have done ICV injection in the fourth ventricle of rats. Any help in this regard would be appreciated.
Because the data in the atlases were obtained from a particular rat/mouse strain (Rat: adult Wistar, 290 g; Mouse: adult C57BL/J6, 26–30 g) the data you are looking for (mouse age 30 days, i.e. for smaller age and body weight , your best option is to scale it down.
yes there is a formula how to scale your coordinates to fit your Lumbda/Bregma distance.
Pls refer to articles listed below.
In short , according to Paxinos and Franklin's the Mouse Brain in Stereotaxic Coordinates - 4th Edition, the distance between bregma and lambda published for 26g-30g animals (3 months) is 4:21mm. your animals are smaller, the distance between bregma and lambda is going to be different. Then you take the distance between bregma and lambda of your animal and divided it by 4.21mm. This value then multiplied by your coordinates. Now you have stereotaxic coordinates adjusted for the size of your mouse brain, (like an cross "X" equation).
also do not forget to use the proper cannula gauge you do not want to miss the ventricle (35 and up). also some pilot study for trial and error would be wright thing to do.