Time–place learning is altered by perinatal low-protein malnutrition in the adult rat

Abstract

Malnutrition produces changes in the central nervous system (CNS) of mammals during development, related to the intensity and timing of the malnutrition insult during the pre- or postnatal period. Protein malnutrition produces irreversible changes in hippocampal formation and some brain stem nuclei. The suprachiasmatic nucleus (SCN) is dramatically altered by low-protein diets during the gestational and perinatal periods. Also, it is known that circadian oscillators regulate physiological, behavioral, and cognitive processes and there is evidence that the time-place learning process exhibits a daily temporal distribution. The aim of this study was to determine the effects of chronic, prenatal, or postnatal malnutrition on daily patterns of the time-place learning process in the adult rat. Forty Sprague-Dawley male 90-day-old rats, were divided into four groups: 10 well nourished controls (Co), 10 chronically (CM), 10 prenatally malnourished (PrM), and 10 postnatally malnourished (PtM) rats. Efficiency in time-place learning was tested by using a behavioral T-maze. Each rat was assayed for 10 trials before considering the final probe of efficiency. Each trial was 60 seconds long, final efficiency was measured by the amount of time the rat took to reach the end of an arm containing a water pot. Each rat was tested in 2-hour spans until completion of a full 24-hour cycle. A Cosinor analysis was used to evaluate acrophase and percentage of rhythmicity. The obtained results suggest that time-place learning process is influenced by the circadian clock. The severity and timing of prenatal or chronic protein malnutrition modifies the acrophase and rhythmicity of the learning circadian pattern, which can impact important cognitive functions.

Brain Structural Networks in Mouse Exposed to Chronic Maternal Undernutrition

“…The development of the central nervous system is a complex process that demands large amounts of energy as well as specific nutritional components (Morgane et al, 2002;Kuzawa et al, 2014;Barrickman, 2016). Since most of brain development occurs prenatally and during lactation, maternal nutrition has been identified as a key factor for brain growth and maturation both in human populations (Ivanovic et al, 2000;Odabaş et al, 2005;Kar et al, 2008) and in experimental animal models (Cordero et al, 1986;Morgane et al, 1993Morgane et al, , 2002Ranade et al, 2008Ranade et al, , 2012Antonow-Schlorke et al, 2011;Durán et al, 2011;Hunter et al, 2016).…”