Cognitive-experimental studies

Cognitive effects Animais Cognitive effects of nicotine have been observed in several species, including humans. Experimental studies have focused primarily on the effects on attention and memory. Cognitive benefits are seen after both acute and chronic administration (Levin et al. 1992). In experimental animals, nicotine improves learning and memory on a variety of tasks. Conversely, the nicotinic antagonist mecamylamine... 

Several recent epidemiological studies have involved examination of populations that consume unusually high levels of fish. One of these, conducted in the islands of the Seychelles, has not so far revealed behavioral and learning impairments in children whose mothers exhibited mercury levels (measured in hair) higher than those typically seen in the United States and European countries. But another study, conducted in the Faroe Islands, turned up evidence of cognitive and behavioral impairments in children. Scientists have struggled to understand why two well-done studies have produced such different outcomes, and some possible reasons have been suggested. The EPA and public health officials have acted on the basis of the Faroe data, out of both caution and also because they seem to be supported by other, more limited data, and by experimental studies. The debate is not so much about whether methylmercury is a developmental toxicant, but rather over the dose required. 

Transgenic mice that overexpress Ab have been used to determine whether vaccines could be produced to reduce the concentration of the peptide in patients with AD. Experimental studies have shown that Ab peptide immunization reduces the cognitive impairments and the formation of plaques in rodent models of AD. This finding led to the development of vaccines for human use and while the phase 1 trials in the UK suggested that the vaccine was safe, more extensive studies in Europe led to the termination of the clinical trials because 5% of the patients develop meningioencephalitis. More studies are presently underway to induce an immune response against Ab without initiating T-cell activation which underlies the inflammatory process in the brain. 

The remainder of this book focuses on these critical issues. In the chapters that follow, I explain the theory and model of schema development that have guided my research, and I describe a number of experimental studies designed to test specific aspects of the theory in the domain of arithmetic story problems. Underlying these chapters are two important premises First, the study of the schema will yield theoretical findings of value to the study of cognition, and second, the schema is the means by which theory can guide practice. With respect to the latter premise, the schema has the potential of being a theoretical construct with practical appli-... 

Experimental studies of context-dependent memory in recent years have established the importance of the effect, but no general cognitive model has been proposed which might explain its operation. The application of the habit routine model may consolidate understanding of several currently studied aspects of memory. Baddeley reports a particularly interesting study, the results of which lend themselves directly to interpretation using the habit routine model. This interpretation of context-dependent memory will additionally lead us into another question of importance for understanding HRS and lma and how these processes are i nitiated ... 

Returning to the contemporary scene, some readers of an experimental study typically become virtual witnesses by engaging in the critical assessment of the laboratory report. As a tool of persuasion, the report provides the reader with a cognitive vision of the laboratory events in ways that recommend endorsement. The reader is invited to critically evaluate the results, the methodology, and the original plan of action. 

In summary, kava appears to have few adverse effects on human functioning. However, there is reason to be cautious in its use because we have limited data from well-controlled experimental studies and clinical trials. Further, there is a paucity of studies on the long-term effects of kava on human cognitive functioning. 

Cenacchi B, Bertoldin T, Farina C, Fiori MG and Crepaldi G (1993). Cognitive decline in the elderly A double blind, placebo-controlled multicenter study on efficacy of phosphati-dylserine administration. Aging, Clinical and Experimental Research, 5, 123-133. 

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