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We measured performance and event-related brain potential (ERP) map latencies in 12 subjects during four visual discrimination tasks to compare the timing of scopolamine effects on information processing and attention. "Topographic component recognition" found ERP map latencies at times of best fit with a component model map. This "common topography"(More)
Twelve subjects were tested with D-amphetamine, yohimbine, clonidine, and a placebo on a task with two levels of stimulus and two levels of response complexity. The purpose of this study was to test the hypothesis that noradrenergic drugs affect early stimulus processes. D-amphetamine speeded reaction time (RT), clonidine slowed it, and yohimbine had no(More)
Many studies have found that cigarette smoking or nicotine improves mental functioning in abstinent smokers. An unresolved issue is whether this improvement is due primarily to a direct facilitation of performance or to relief of the impairment caused by nicotine withdrawal. We evaluated the performance of 12 non-smokers before and twice (15 and 45 min)(More)
Several studies have shown that d-amphetamine (DAMP) speeds mean reaction time (RT). However, the use of mean RT may obscure important aspects of the drug response. Therefore we applied the Poisson-Erlang (PE) stochastic model of choice reaction time proposed by Pieters (1985) to the RT distribution. This model proposes that the RT distribution is generated(More)
Hyperactivity in children has been attributed to underarousal, maturational lag, and both. Using event-related potentials (ERPs) and EEG spectra, we compared hyperactive children with age-matched normal controls. Neither underarousal nor maturational lag explained our findings, and we concluded that these explanations are now too simple to be useful. We(More)
In a previous study of the effect of age on information processing, both age and stimulus complexity slowed reaction time (RT) and the latency of the P300 component of the brain event-related potential (ERP). The aim of the present study was to compare the effects of scopolamine (an anticholinergic) with the previously noted effects of age. The choice of(More)
Models of information processing currently popular in cognitive psychology divide the reaction process into a series of discrete separable stages. The distinction between one stage and another is verified by the additive factors method (AFM) as defined by Sternberg (1969). Task factors that do not interact with each other are inferred to affect different(More)
Human performance on a choice-reaction time task (Eriksen task) has been simulated by a neural network. In simulations, the network captures many features of normal performance. In addition, changing gain in different layers produces changes that simulate different drug-induced changes. Data from a similar choice-reaction time task have been reanalyzed to(More)