CHICAGO: In a first-of-its-kind study, UT Dallas researchers in the Aging & Memory Research Laboratory have determined that while short-term exposure to a high-fat diet can cause learning and memory to fade, that memory can recover over a longer period of time.
The same study also showed that in rats, the high-fat diet caused male animals to become severely diabetic after eating it for three to 12 months, while females did not.
The research by Erica Underwood MS’12, an applied cognition and neuroscience doctoral student, focused on animals that were fed a high-fat diet, compared to age-matched controls.
After three months, the high-fat diet caused both physiological and behavioral impairments to the subjects. The physiological changes were marked by reduced excitability of the primary output neurons in the hippocampus, which is the part of the brain involved in most forms of memory consolidation.
The behavioral impairments were demonstrated through severe deficits in spatial memory in both male and female animals, assessed with two independent tests. After animals placed in a grid-marked box containing two Lego-like toy objects became familiar with the box and location of the objects, the researchers then moved one object to a new location.
Later, when placed in the box, rats that ate high-fat foods for 12 weeks appeared confused and had difficulty remembering the novel location of the object. Similar severe memory impairments also were seen using a different spatial memory task.
After 12 months, physiological impairments in the hippocampus worsened, but the behavioral impairments—cognitive measures of learning and memory—went away.