Can a reward-based behavioural test be used to investigate the effect of protein–energy malnutrition on hippocampal function?

Abstract

Our laboratory is investigating the effects of protein-energy malnutrition (PEM) on cognitive outcome following global ischemia. Here, we investigated whether PEM independently impairs working memory in the T-maze and if the associated food reward reverses PEM. Gerbils were fed 12.5% (control diet) or 2% protein. A loss of body weight (20.1%) in the 2% protein group and decreased food intake and serum albumin concentration compared to controls (17.5% and 18.2%, respectively) indicated that PEM was achieved. Based on T-maze criterion frequently used in ischemia studies, no difference was observed in the mean (+/- SEM) number of trials required (control 5.2 +/- 0.7; PEM 4.9 +/- 0.4; p = 0.758) or the number of animals reaching criterion (control 10/12; PEM 12/12; p = 0.140). Using more stringent criterion, PEM animals required fewer trials (control 7.3 +/- 0.7; PEM 5.4 +/- 0.4; p = 0.035), and more reached criterion (control 8/12; PEM 12/12; p = 0.028). PEM may increase motivation to obtain a food reward.

Protein-Energy Malnutrition Developing after Global Brain Ischemia Induces an Atypical Acute-Phase Response and Hinders Expression of GAP-43

“…Future studies with Golgi-Cox staining and electrophysiology to examine dendritic morphology and synaptic strength, respectively, will also be needed to reinforce the study results. Our findings are reminiscent of the extensive literature on the adverse effects of perinatal malnutrition on synaptic plasticity in the hippocampal formation [43] , [44] , although some of these studies are limited by flaws in the methodology for the nutritional regimens (reviewed in [45] ).…”

Transient forebrain ischemia induces impairment in cognitive performance prior to extensive neuronal cell death in Mongolian gerbil (Meriones unguiculatus)

“…Another study on gerbils has reported that the animals had more difficulty learning the win-stay rule than the win-shift rule [ 3 8 ]. In most of these studies, the win-shift task, not the win-stay task, was used to evaluate cognitive impairment via examination of food-searching behavior after ischemia [ 23 30 ]. Further, the passive avoidance test has also been used to evaluate cognitive impairment after ischemia [ 4 29 33 ].…”