Specific characteristics of cholinergic mechanisms of short-term memory in monkeys for different types of visual information: the effects of amizil.

Experiments on rhesus macaques were used to study the relationship between the characteristics of delayed visual differentiation and stimulus properties in conditions of pharmacological treatment with the m-cholinoreceptor blocker amizil, with the aim of identifying how modification of cholinergic structures affects different types of information. Disturbances to short-term memory for all stimuli consisted of reductions in the duration of retention and increases in motor reaction times, but occurred at different doses of the blocker: amizil at a dose of 0.3 mg/kg significantly decreased the retention duration for information relating to spatial relationships. Delayed discrimination of shape, contrast, and size worsened after treatment with amizil at a dose of 0.45-0.50 mg/kg, while decreases in the duration of short-term storage of information relating to color started after amizil doses of 0.6-0.8 mg/kg. It is suggested that the short-term memory system includes a set of neurophysiological mechanisms in which the cholinergic structures are organized differently and whose specific properties result in differences in the characteristics of short-term storage of different types of visual information.