RAPID EGG-YOLK EMBEDDING OF WHOLE RAT-BRAIN FOR FROZEN OR VIBRATOME SECTIONING

A simple method of rat brain embedding into egg yolk facilitates seria l sectioning of the whole brain in coronal plane. The sections are com pact and can easily be treated by such free floating techniques as sil ver impregnation or immunohistochemistry. Unembedded material is hard to process in this way, as caudal parts of the brain (including occipi tal cortices, cerebellar convolutions, and brain stem) form separate p ieces that must be treated individually, and their unfolding and appro priate positioning onto slide is difficult. A simple and rapid embeddi ng protocol greatly simplified processing the large number of sections . This technique may be of practical importance in several cases where frozen or vibratome brain sections are to be processed by floating te chnique.