Delayed alternation performance in rats following recovery from early iron deficiency

Early iron deficiency (ID) is one of the most common nutrient deficiencies in both developed and developing countries. This condition has been linked to perturbations in myelin formation, alterations of monoamine neurotransmitter systems particularly in the striatum, and deficits in energy metabolism particularly in the hippocampus (HP) and prefrontal cortex (PFC) in rats. Early ID has also been traced to long-term behavioral consequences in children in domains linked to these neuropathologies. The current experiment assesses formerly iron deficient (FID) adult rats on a delayed alternation (DA) task - a procedure thought to be sensitive to PFC dysfunction. Rat dams were started on an iron deficient chow at gestational day (G) 2 and maintained on this diet until postnatal day (P) 7; behavioral training began at P 65 when animals were iron replete. FID animals exhibited accelerated acquisition (p=0.002) and fewer errors (p=0.003) on the DA task compared to controls. These findings may reflect an imbalance between hippocampal and prefrontal modulation of this behavior most likely emanating from long-term hippocampal disinhibition by early ID that persists in spite of early iron treatment from P 7.