Methylphenidate during early consolidation affects long-term associative memory retrieval depending on baseline catecholamines

RATIONALE: Synaptic memory consolidation is thought to rely on catecholaminergic signaling. Eventually, it is followed by systems consolidation, which embeds memories in a neocortical network. Although this sequence was demonstrated in rodents, it is unclear how catecholamines affect memory consolidation in humans. OBJECTIVES: Here, we tested the effects of catecholaminergic modulation on synaptic and subsequent systems consolidation. We expected enhanced memory performance and increased neocortical engagement during delayed retrieval. Additionally, we tested if this effect was modulated by individual differences in a cognitive proxy measure of baseline catecholamine synthesis capacity. METHODS: Fifty-three healthy males underwent a between-subjects, double-blind, placebo-controlled procedure across 2 days. On day 1, subjects studied and retrieved object-location associations and received 20 mg of methylphenidate or placebo. Drug intake was timed so that methylphenidate was expected to affect early consolidation but not encoding or retrieval. Memory was tested again while subjects were scanned three days later. RESULTS: Methylphenidate did not facilitate memory performance, and there was no significant group difference in activation during delayed retrieval. However, memory representations differed between groups depending on baseline catecholamines. The placebo group showed increased activation in occipito-temporal regions but decreased connectivity with the hippocampus, associated with lower baseline catecholamine synthesis capacity. The methylphenidate group showed stronger activation in the postcentral gyrus, associated with higher baseline catecholamine synthesis capacity. CONCLUSIONS: Altogether, methylphenidate during early consolidation did not foster long-term memory performance, but it affected retrieval-related neural processes depending on individual levels of baseline catecholamines

Social Policy and Cognitive Enhancement: Lessons from Chess

Should the development of pharmacological cognitive enhancers raise worries about doping in cognitively demanding activities? In this paper, we argue against using current evidence relating to enhancement to justify a ban on cognitive enhancers using the example of chess. It is a mistake to assume that enhanced cognitive functioning on psychometric testing is transferable to chess performance because cognitive expertise is highly complex and in large part not merely a function of the sum specific sub-processes. A deeper reason to doubt that pharmacological cognitive enhancers would be as significant in mind sports is the misleading parallel with physical enhancement. We will make the case that cognitive performance is less mechanical in nature than physical performance. We draw lessons from this case example of chess for the regulation of cognitive enhancement more generally in education and the professions. Premature regulation runs the risk of creating a detrimental culture of suspicion that ascribes unwarranted blame