The writer cites the example of vasopressin and ep

单项选择题

Memory can be both enhanced and impaired by the use of drugs. To date, most of the research in this area has focused on the short- and long-term effects of alcohol. Overall, the results show that alcohol interferes with the ability to encode new information but has relatively little effect on the retrieval of data already stored in long-term memory(Bimbaum et al., 1978). Heavy use of alcohol, however, may result in significant memory loss. In some cases, everything that was said or done while intoxicated is completely blocked out of memory. The person may fail to remember even highly significant events - such as having injured somebody! In extreme cases, chronic alcoholism may result in Korsakoff" s psychosis, a disorder characterized by gross memory defects and disorientation. Sufferers of Korsakoff" s psychosis may lose track of their own names, where they came from, or where they are. The effects of marijuana on memory are far less clear. In one study, subjects who had smoked marijuana experienced unusual difficulty in transferring information from short- to long-term memory. They could recall items for a brief period, but as time progressed, they forgot more and more of the information(Klatzky, 1980). Like alcohol, marijuana appears to interfere with the ability to encode and store data in long-term memory. There are drugs that actually enhance memory. Perhaps the most promising of these is DDAVP, a synthetic drug related to the hormone vasopressin, which is secreted by the pituitary gland. Vasopressin appears to increase a person" s motivation and enjoyment of learning, and these are important factors in improving one" s memory. Taken in the form of a nasal spray, DDAVP has significantly increased subjects" ability to recall information on cue. Another hormone, epinephrine, may also aid memory. Gold and Delaney(1981)discovered that the memory-enhancing effects of epinephrine were greatest when it was administered right after a learning session. Delays in administering the epinephrine markedly reduced its effectiveness. These results suggest that naturally occurring memory problems may be due in part to inadequate levels of vasopressin or epinephrine(McGaugh, 1983).

The writer cites the example of vasopressin and epinephrine in order to show that______.

A．man"s memory is changeable
B．short-term memory can be transferred to long-term memory
C．hormones enhance memory
D．memory and drugs are related