[Conditioning of thrombocyte count changes and other components of human capillary blood]

An unconditioned rise in the number of platelets in the capillary blood of man, induced by dynamic exercise in the form of pedalling an ergobicycle (18 mkp/sec, 30 min), was conditioned to blinking light signal of low intensity in 5 healthy men. After 4, 7 and 11 reinforcements (1 per day) in all cases a conditioned rise could be observed, which remained extant---although slightly weaker--for 18 days without any reinforcement after the last trial. The authors assume that this fact is pointing out a direct participation of the platelets on nervous processes.