Axonal transport in the habenulo-interpeduncular tract

The accumulation of radioactivity in the interpeduncular nucleus was studied as a function of time after injection of tritiated leucine into the habenula. Peaks of labeled material are seen at 4 h (minor peak) and 4 days (major peak) so that the rates of transport are very similar to those in the nigro-striatal tract. The rate of decay of label is also very similar to that seen in the neostriatum after injections of tritiated leucine into the substantia nigra. The only difference between the two tracts is that the amount of radioactivity carried by fast transport appears relatively larger in the habenulo-interpeduncular tract than in the nigro-striatal system.