Cue-Potentiated Feeding In Rats

Abstract

Cue-potentiated feeding (CPF) describes the stimulation of food consumption by cues that have become associated with food. Determining under what conditions CPF occurs is important for understanding whether exposure to food cues contributes to overeating. A history presented in Chapter 1 describes how the study of CPF developed from incidental findings in early experiments to Weingarten’s (1983) influential paper, through to contemporary models that focus primarily on the neural circuits underlying CPF. There have been fewer attempts to characterise the broader nature of the effect, particularly in relation to whether CPF is ‘specific’ to the paired food. This formed the general focus of the present thesis. Chapter 2 outlines three experiments using a training procedure in which laboratory rats received intermixed exposures to a ‘Plus’ context containing palatable food and to a ‘Minus’ context containing no food. CPF was found to be specific to the training food even when testing a palatable and familiar alternative. However, contexts paired with a variety of foods enhanced consumption of other foods never eaten in that environment. Experiments in Chapter 3 explored individual differences in CPF and found that the effect did not correlate with consumption of palatable food at baseline or during training. Results also suggested that consumption of palatable food in training was not matched by an equivalent reduction in home-cage chow intake. Chapter 4 reports a series of experiments in which methodological changes hypothesised to enhance the CPF effect reversed the predicted pattern of consumption. These results are discussed with reference to theories of incentive contrast. The effects of diet-induced obesity on CPF were explored in Chapter 5. The present results are integrated with existing literature and directions for future research are outlined in Chapter 6, which discusses CPF with reference to specificity and variety; individual differences; and the sensitivity of the effect to procedural parameters.