Kupalov's concept of shortened conditional reflexes: psychophysiological and psychopharmacological implications.

In the regulation of cortical excitability tonus, Kupalov described a particular acquired, learned mechanism, the shortened conditional Reflex (SCR). SCR is an essential mechanism by which an adequate cortical tonus is established by environmental cues as an anticipatory set-up preparing the individual qualitatively and quantitatively for expected forthcoming events. An original physiological example is given, the conditional "transfer" of motor behavior at cortical electrical stimulation.

Nootropic drugs and aging.

Nootropics are drugs which ameliorate the functional "plasticity" of the central nervous system. The nootropic drug acts at the telencephalic level through a series of bioenergetic, hemorheological, microcirculatory and neurochemical mechanisms. As to this, recent data show a facilitation by piracetam, of the efficiency of the central cholinergic system.

Piracetam facilitates retrieval but does not impair extinction of bar-pressing in rats.

Rats were trained on a continuously reinforced bar-press response for water reward. Seven days later they were retested for retention, with or without pretest injection of the nootropic drug, piracetam. Drug-treated animals had significantly shorter response latencies than saline-treated animals.