Scientists continue to explore the remarkable protective effect of nicotine – the addictive chemical in tobacco – on the brain. One recent study has found that one of nicotine's metabolites, cotinine, may improve memory and protect brain cells from diseases such as Alzheimer's and Parkinson's. Another new study shows that nicotine can help improve some of the learning and memory problems associated with hypothyroidism. Such studies suggest that nicotine – or drugs that mimic nicotine – may one day prove beneficial in the treatment of neurological disorders