PALLIDO-THALAMO-MOTOR CORTICAL CONNECTIONS - AN ELECTRON-MICROSCOPIC STUDY IN THE MACAQUE MONKEY

We combined the retrograde transport of horseradish peroxidase conjuga ted to wheat germ agglutinin (WGA-HRP) technique and degenerating elec tron microscopic investigations to confirm the motor cortical area pro jection from the medial pallidal segment (GPm) via the thalamic nucleu s ventralis lateralis pars oralis (VLo). We found first degenerated bo utons arising from the GPm make synaptic contact with the somata and p roximal dendrites of VLo neurons containing WGA-HRP reaction products transported retrogradely from motor area.