The Federal Reserve Bank of Minneapolis said its regional economy should improve in 2011, helped by employment gains and higher businesses sales.

“Optimism is back,” Toby Madden, a regional economist at the bank, said in a statement posted on the bank’s website today.

The U.S. economic expansion hasn’t been strong enough to reduce the unemployment rate, leading Fed officials last week to keep in place their plan to expand record monetary stimulus. They’ve left their target for the federal funds rate, which covers overnight interbank loans, near zero for two years and undertaken a second round of large-scale Treasuries purchases.

The Minneapolis Fed serves a region that includes Minnesota, Montana, North Dakota and South Dakota, and parts of Wisconsin and Michigan. It is led by the bank’s president, Narayana Kocherlakota.