Deferred imitation has recently surfaced as a hallmark measure of nonverbal declarative memory. In two experiments, we examined the developmental origins of deferred imitation during early infancy. Six- and 9-month-old human infants observed an experimenter perform specific actions with multiple objects. The infants' ability to reproduce those actions was assessed following a 24-hr delay. With ...

We discuss several lines of evidence refuting the hypothesis that procedural or declarative memories are processed/consolidated in sleep. One of the strongest arguments against a role for sleep in declarative memory involves the demonstration that the marked suppression or elimination of REM sleep in subjects on antidepressant drugs or with brainstem lesions produces no detrimental effects on c...

Most research on neurodevelopmental disorders has focused on their abnormalities. However, what remains intact may also be important. Increasing evidence suggests that declarative memory, a critical learning and memory system in the brain, remains largely functional in a number of neurodevelopmental disorders. Because declarative memory remains functional in these disorders, and because it can ...

During the past decade, a large body of research has shown that memory traces can become labile upon retrieval and must be restabilized. Critically, interrupting this reconsolidation process can abolish a previously stable memory. Although a large number of studies have demonstrated this reconsolidation associated amnesia in nonhuman animals, the evidence for its occurrence in humans is far les...

The distinction between procedural and declarative memory is widely accepted in the memory literature. Converging evidence makes a strong case that the medial aspects of the temporal lobes and the diencephalon subserve the declarative memory system. However, the neuroanatomy of procedural memory is much less clear. In animal studies, damage to the basal ganglia has been found to affect procedur...

Sleep is critically involved in the consolidation of previously acquired memory traces. However, nocturnal sleep is not uniform but is subject to distinct changes in electrophysiological and neuroendocrine activity. Specifically, the first half of the night is dominated by slow wave sleep (SWS), whereas rapid eye movement (REM) sleep prevails in the second half. Concomitantly, hypothalamo-pitui...

Memory can be divided into two categories: memory of events or facts, and memory for skills and rules. These are often called declarative memory and procedural memory (Squire, 1986; Tulving, 1985), or they are often characterized as ‘‘what’’ memory and ‘‘how’’ memory. An accumulation of declarative memories will comprise knowledge; an accumulation of procedural memories will comprise intelligen...

The neurotransmitter acetylcholine is considered essential for proper functioning of the hippocampus-dependent declarative memory system, and it represents a major neuropharmacological target for the treatment of memory deficits, such as those in Alzheimer's disease. During slow-wave sleep (SWS), however, declarative memory consolidation is particularly strong, while acetylcholine levels in the...

Electrical stimulation of the brain is a unique tool to perturb endogenous neural signals, allowing us to evaluate the necessity of given neural processes to cognitive processing. An important issue, gaining increasing interest in the literature, is whether and how stimulation can be employed to selectively improve or disrupt declarative memory processes. Here, we provide a comprehensive review...

In explicit sequence learning tasks, an improvement in performance (skill) typically occurs after sleep-leading to the recent literature on sleep-dependent motor consolidation. Consolidation can also be facilitated during wakefulness if declarative knowledge for the sequence is reduced through a secondary cognitive task. Accordingly, declarative and procedural consolidation processes appear to ...