دانلود رایگان مقاله انگلیسی حافظه انسان: اثرات وابسته حالت مغز هنگام تحریک - الزویر 2017

Zaphod Beeblebrox — a character in Douglas Adams, comic sci-fi novel ‘‘The Hitchhiker’s Guide to the Galaxy [1]’’ — is in a rather confused state when his spaceship lands on planet ‘Vogtsphere’. Conveniently, he has at hand a ‘thinking cap’, a device that electrically stimulates the brain in order to improve cognitive function. This intuition that electrical stimulation modifies brain function is not only evident in various sci-fi novels, but actually has a long standing history in cognitive neuroscience. For instance, over half a century ago Wilder Penfield [2] pioneered the technique of pre-surgical mapping, whereby brain areas that underlie specific cognitive and motor functions are mapped by applying electrical pulses to the brain tissue. A given area is assumed to be functionally relevant if electrical stimulation interferes with the associated cognitive or motor function, as manifested, for example, by interruptions or difficulties in the naming of objects during the stimulation of language areas (Wernicke’s area, for example). But can this same stimulation technique be utilized in a way that does not disrupt but instead enhances cognitive performance? As they reported very recently in Current Biology, Ezzyat et al. [3] have developed a new approach to brain stimulation, obtaining results that show that brain stimulation is capable of improving memory, but only when applied during certain brain states.