Cognitive impairment is a widely reported side effect of many commonly used drugs. Even a mild, untoward effect on an essential function such a linguistic behavior, a directly observable product of complex cognitive processes, is disruptive to daily life. Nevertheless, the mechanisms underlying a drug's impact on cognition are poorly understood. This lack of understanding impedes the ability to predict both the effects of drugs in development and the degree to which an individual is vulnerable to the cognitive impact of a particular agent. Topiramate (TPM, an antiepileptic drug) is, with increasing frequency, being prescribed for a range of conditions including migraine prophylaxis, obesity and pain. It is a prime example of a drug that causes speech and language problems severe enough in some patients to result in discontinuation of therapy. For reasons not well understood, TPM has a poorer cognitive profile than many of the older antiepileptic drugs. The investigators' rational for this study is that it will offer insight into the mechanisms underlying drug-induced cognitive deficits.