Electrophysiological evidence for enhanced representation of food stimuli in working memory.

Femke Rutters,Sanjay Kumar,Suzanne Higgs,Glyn W Humphreys

doi:10.1007/s00221-014-4132-5

Abstract

Studies from our laboratory have shown that, relative to neutral objects, food-related objects kept in working memory (WM) are particularly effective in guiding attention to food stimuli (Higgs et al. in Appetite, 2012). Here, we used electrophysiological measurements to investigate the neural representation of food versus non-food items in WM. Subjects were presented with a cue (food or non-food item) to either attend to or hold in WM. Subsequently, they had to search for a target, while the target and distractor were each flanked by a picture of a food or non-food item. Behavioural data showed that a food cue held in WM modulated the deployment of visual attention to a search target more than a non-food cue, even though the cue was irrelevant for target selection. Electrophysiological measures of attention, memory and retention of memory (the P3, LPP and SPCN components) were larger when food was kept in WM, compared to non-food items. No such effect was observed in a priming task, when the initial cue was merely identified. Overall, our electrophysiological data are consistent with the suggestion that food stimuli are particularly strongly represented in the WM system.

Highlights

In our current obesogenic environment food cues are found all around us; from shop displays and television adverts, to pictures of food and eating in magazines
In lean subjects, deliberately holding food items in working memory (WM) is effective in guiding attentional selection when food stimuli are re-presented in a display with WM-based guidance of attention from food being stronger than the guidance from neutral stimuli (Higgs et al 2012; Rutters et al 2013)
Reaction times were strongly affected by the re-appearance of a food cue, but only when the cues were held in WM rather than merely being attended to, as shown in the priming condition, designed to match the visual sequence used in the WM condition

Summary

Introduction

In our current obesogenic environment food cues are found all around us; from shop displays and television adverts, to pictures of food and eating in magazines. In lean subjects, deliberately holding food items in WM is effective in guiding attentional selection when food stimuli are re-presented in a display with WM-based guidance of attention from food being stronger than the guidance from neutral stimuli (Higgs et al 2012; Rutters et al 2013). In these experiments, participants were presented with a food or non-food (neutral) cue to either attend to or hold in WM, and subsequently they had to search for a shape target (cf (Soto et al 2005)). Reaction times were strongly affected by the re-appearance of a food cue, but only when the cues were held in WM rather than merely being attended to, as shown in the priming condition, designed to match the visual sequence used in the WM condition

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Conclusion