Neuronal mechanisms of goal-directed behaviour in monkeys.

The present paper is a review of investigations by the author and coworkers on rearrangements of impulse activity of single cortical neurons and subcortical structures in monkeys during the performance of delayed alternation choice. In prefrontal and parietal cortices as well as in the head of the striate nucleus and in the anterior ventral thalamic nucleus spatioselective neurons are found which detect cue location. This spatial selectivity is retained within the entire delay. Neurons of shortterm memory and units involved the realization of a forthcoming goal-directed movement are found in the prefrontal and parietal cortices. Basing on morphophysiological data intracortical reverberation might be considered a principal mechanism of storing the relevant information in shortterm memory. Intracortical neuronal circuits in the prefrontal cortex and long thalamocortical loops of direct connections and feedback in the parietal cortex may ensure this type of reverberation. The above brain structures comprise a dynamic constellation which provides extraction from longterm memory and storing in the shortterm memory of information about the conditioned signal properties and the relevant motor program.