Can drinking too much alcohol shrink the brain?

Yes. Chronic alcohol abuse can cause atrophy or shrinage of the brain. Imaging studies such as ct scan of the brain can show enlargment of the ventricles and sulci which are "empty" fluid filled areas of the brain and correspond with shrinkage of healthy brain tissue. Animal studies of rodents exposed to chronic alcohol show loss of neurons or brain cells in parts of the brain.
Yes. Alcohol has been clearly known to show brain shrinkage in MRI studies.

Related Questions

How is brain affected when a person passes out from drinking too much alcohol?

Alcohol. Effects depend on the amount consumed. Small to moderate consumption causes reduced risks of blood clots, stone formation, diabetes & rheumatoid arthritis. Large consumption causes impaired memory & vision, anemia, cardiomyopathy, hepatitis, cancer mouth/esophagus, gastritis, pancreatitis, diabetes type 2, depression, anxiety, psychosis, insomnia, panic, cravings.
Loss of brain cells. Using too much alcohol can kill brain cells. If you pass out you have definitely had to much and it is time to cut back or stop completely.