In vivo tract tracing using manganese-enhanced magnetic resonance imaging

In vivo tract tracing using manganese-enhanced magnetic resonance imaging By: R.G Pautler et. al, A. P. Koretsky This was one of the first studies validating the use of manganese-enhanced magnetic resonance imaging (MeMRI) as a tract tracer. In order for an agent to function as a tract tracer it must have the ability to cross from one neuronal synapse to another, and it must also be detectable while in the cell. A tract tracer can be defined as a retrograde tracer, anterograde tracer, or both. Prior to manganese, other tracing agents utilized included biotinylated dextran, horseradish peroxidase, fluorogold, and HSV. However, all of these agents must be in fixed tissue in order to be detected, making the techniques fatal to the subjects. Pautler and Koretsky were able to prove manganese was not only a tract tracing agent, but could be utilized in vivo after they successfully defined the olfactory and visual pathways in conscious rats using detectable MRI. This discovery, along with the established characteristic of manganese to accumulate in neurons in an activity dependent manner, makes MeMRI a powerful and feasible technique for neurological studies, structural as well as functional. ~A very tired and forgetful JI.