Object dimensions underlying food representations in visual cortex

Recent research has identified two specialized areas in the brain's visual cortex that respond uniquely to food representations. These findings challenge earlier theories that attributed food selectivity solely to mid-level features such as shape, texture, or colour. To investigate further, two functional magnetic resonance imaging (fMRI) experiments were conducted on the same group of participants.

The study aimed to elucidate the specific dimensions underlying food representations in both the lateral and ventral occipitotemporal cortex (OTC).

The results demonstrated a clear distinction between the lateral and ventral OTC when it comes to food representations. In the lateral OTC, food-related representations were closely linked to properties related to actions, such as manipulability, which are shared with other graspable objects. In contrast, the ventral OTC showed a sensitivity to surface object properties like colour and the overall ensemble configuration of food items.

This differentiation was supported by the observation that the lateral OTC demonstrated heightened responsiveness to individual objects against various backgrounds and performed equally well with both color and greyscale stimuli. On the other hand, the ventral OTC exhibited a stronger preference for colored stimuli and food items presented without a distinguishable background.

To further explore these differences, the researchers employed topographic artificial neural networks, which were designed to mirror the spatial organization found in the OTC. These networks revealed two distinct clusters of food-selective units, each responding differently based on sensitivity to ensemble statistics. This suggests that lateral food representations are associated with action-relevant properties that are also found in other objects that can be manipulated, while ventral food representations stem from surface-based visual features that are crucial for the identification of food items.

In summary, the study provides compelling evidence that the brain distinguishes between two types of food representations in the visual cortex. Lateral OTC areas are more attuned to action-related properties that are common across food and other manipulable objects, whereas ventral OTC areas are more sensitive to the visual features necessary for recognizing and identifying specific food items.

These findings underscore the complexity of how our brains process and distinguish between different types of visual information, particularly in the context of everyday objects like food.