Research on information processing during different states of sleeping and waking revealed that under specific conditions of conditioning and learning storage and retrieval of information, based upon repeated experience, occurs. Research now focuses on the role of specific thalamic nuclei in the processing of information during wake-sleep states. The experiments are based upon the electrophysiological concept of thalamic 'transfer ratio'. An important issue concerns the question whether the gating function of the thalamus, realized by the transfer ratio, is of qualitative rather than of quantitative nature and if so, how this qualitative gating is realized. That analysis must make it possible to determine the degree of openness of brain systems to external information and, thus, to learning.
Research now aims at the genesis of spike-wave complexes and their relation to sleep spindles.
Furthermore, it is going to be investigated what parts of the brain are responsible for and contribute to the genesis and the control of spike-wave complexes and sleep spindles. The work on the development of attachment in baby macaques and its relation to the control of fear during exploration led to the conclusion, that maternal deprivation did increase the probability of monkeys becoming phobic. Phobic behavior also devel-oped in animals, which had the opportunity to attach to their mothers, but in a much smaller number of animals than was the case in animals that did not have the opportunity to attach to their mother. In order to investigate the contribution of mothers and of babies in the development of attachment and the control of fear a line of research has been started in which this problem is attacked by cross-fostering in guinea pigs. In line with this research experiments are under way in which it is investigated whether at-tachment and imprinting are the result of the same learning process.