Some of the profound effects alcohol has on the brain were discovered years ago through pathological studies at autopsy. However, the recent development of new tools for structural and functional brain imaging has enabled researchers to expand upon this earlier knowledge. For example, some imaging studies have revealed that chronic alcohol consumption causes cortical loss, some of which is reversible with abstinence. Other studies have found that alcohol acts as a global central nervous system depressant, with chronic use resulting in reduced activity that can take a month or more to recover. Finally, imaging tools are also beginning to shed light on which brain regions are active when an alcoholic has the urge to drink.