Jackson told the Manchester Evening News:"Lee scored the winner against Portsmouth and it was great to hear fans singing his name.
"Many players can often be misunderstood, particularly when speculation is flying about, and Lee has found the situation difficult.
"We all know the transfer window system can bring pressures but the secret is to keep going and work the best you can and this is what Lee has been doing."
McCulloch's goal on the weekend was his fifth of the campaign, equalling his record from last season.