Caffeine attenuates scopolamine-induced memory impairment in humans

Abstract

Caffeine consumption can be beneficial for cognitive functioning. Although caffeine is widely recognized as a mild CNS stimulant drug, the most important consequence of its adenosine antagonism is cholinergic stimulation, which might lead to improvement of higher cognitive functions, particularly memory. In this study, the scopolamine model of amnesia was used to test the cholinergic effects of caffeine, administered as three cups of coffee. Subjects were 16 healthy volunteers who received 250 mg caffeine and 2 mg nicotine separately, in a placebo-controlled double-blind cross-over design. Compared to placebo, nicotine attenuated the scopolamine-induced impairment of storage in short-term memory and attenuated the scopolamine-induced slowing of speed of short-term memory scanning. Nicotine also attenuated the scopolamine-induced slowing of reaction time in a response competition task. Caffeine attenuated the scopolamine-induced impairment of free recall from short- and long-term memory, quality and speed of retrieval from long-term memory in a word learning task, and other cognitive and non-cognitive measures, such as perceptual sensitivity in visual search, reading speed, and rate of finger-tapping. On the basis of these results it was concluded that caffeine possesses cholinergic cognition enhancing properties. Caffeine could be used as a control drug in studies using the scopolamine paradigm and possibly also in other experimental studies of cognitive enhancers, as the effects of a newly developed cognition enhancing drug should at least be superior to the effects of three cups of coffee.

Effects of caffeine on learning and memory in rats tested in the Morris water maze

“…The data presented above agree with previous studies on humans suggesting an improving effect of caffeine on memory (3)(4)(5)(6)(7) and show that the Morris water maze task is a good model for the study of this effect. Our results also agree with most of the previous studies reporting improving effects of caffeine in animal models of learning and memory.…”

“…Valzelli et al (25) reported that caffeine improved memory recall of poor learning mice. Riedel et al (4) reported that caffeine attenuated the scopolamineinduced impairment of free recall from shortand long-term memory and of quality and speed of retrieval from long-term memory in a word learning task in humans.…”

“…There are many reports showing that caffeine may ameliorate amnesia in human beings, particularly in cases of age-related cognitive decline (3), scopolamine-induced amnesia (4), and electroconvulsive therapy (5,6). Many of these studies with human subjects are not specifically addressed to memory issues (5,7) and interpretations of the results may be difficult due to interference of the previous caffeine consumption habits and heterogeneity of the samples.…”

Is Caffeine a Cognitive Enhancer?

“…Caffeine was found to either (1) exert no effects on free recall performance in sixteen studies [7][8][9]11,[21][22][23][24][25][26][27][28][29][30][31][32]; (2) improve recall in six studies [33][34][35][36][37][38]; or (3) impair recall in three studies [8,12,39].…”

Effects of Isradipine, a Dihydropyridine-Class Calcium Channel Antagonist, on D-Methamphetamine-Induced Cognitive and Physiological Changes in Humans

“…The Finger Tapping Task (FTT) (see Riedel et al 1995) is a manual test of motor speed. Subjects were required to finger-tap a response button as quickly as possible during a short period of time (60 s).…”