Neuronal processing of food pictures

Abstract

The aim of this study was to explore the neuronal representations that underlie the perception and recognition of visual presented food cues in black and white as well as colored form when contrasted against face, house, and their scrambled counterparts. A theoretical framework published by Mesulam (1998) was used that stated that neuronal concepts and higher order cognitive functions are represented in large scale distributed networks across the human cortex. These functions are provided by transmodal areas, which bind sensory specific properties of object classes into coherent conscious representation. The sensory representations in turn are stored in modality specific areas that represent this content with a gradient from low-level feature encoding up to abstract object encoding. Through this framework a distributed food network was defined that should be responsible for the encoding of visual food cues, the anticipation of food's tastiness, and thereward evaluation of food intake. The results revealed that faces activate the fusiform face area (FFA), prefrontal regions, and parieto-occipital cortex. On the other hand responded the parahippocampal place area (PPA) to houses. Food pictures activated the prefrontal cortex, orbitofrontal cortex, insula, inferior temporal cortex, and parieto-occipital cortex. Moreover, object categories contrasted against their scrambled counterparts confirmed the results found through the contrasts reported above. An influence of color was found in prefrontal cortex, motor cortex, cingulate cortex, parieto-occipital cortex, insula, and subcortical regions across the different contrasts. The results of this study support the assumption that visual food cues are represented in a large scale distributed network across the human cortex. In this network the inferior temporal cortex is responsible for food object encoding, the insula for the processing of food's anticipated tastiness, the orbitofrontal cortex for expected reward evaluation, prefrontal regions for action planning, the parieto-occipital cortex for spatial attention processes, and the cingulate cortex for emotional salience. Further are the activation of FFA through faces and that of the PPA through houses consistent with findings in the literature. The influence of color showed that activity within regions responsible for action planning, action execution, motivation, attention, and emotional awareness is altered.