How do we manage to recognise and use thousands of objects every day?

Recognizing objects is essential for survival: animals rely on it to find food, escape predators, or choose mates. In humans, this ability has become even more complex because we live surrounded by artificial objects. But how does the brain recognize and organize this information?

A team of researchers led by Alessio Fracasso used functional magnetic resonance imaging (fMRI) and a technique called population receptive field analysis (which helps understand how groups of neurons respond to different stimuli) to examine how different brain regions respond to manipulable objects, such as hammers or tweezers. They tested two action-related dimensions: the type of grip and the force required to use the object.

By presenting images of objects arranged according to these dimensions, the scientists observed that brain responses were not random: they formed continuous patterns, true “content maps” (contentopic maps), in both ventral and dorsal visual areas. These maps are consistent across individuals, specific to each dimension, and independent of other visual maps, such as those representing the object’s position in the visual field. This organization may make processing faster and more efficient, reducing energy costs and facilitating object discrimination.

The results suggest that the brain uses topography not only for sensory information but also for functional aspects of objects, which are crucial for everyday actions. This discovery paves the way for new approaches in neuroscience, motor rehabilitation, and even robotics, where understanding how the brain encodes interaction with objects can inspire more intelligent systems. This study was published in the scientific journal NeuroImage, in the article Contentopic mapping in ventral and dorsal association cortex: The topographical organization of manipulable object information, as a part of research project 203/20 - Dynamic eye-movement encoding in human cortex using ultra-high field fMRI (7Tesla), supported by the Bial Foundation.

ABSTRACT

Understanding how object information is neurally organized is fundamental to unravel object recognition. The best-known neural organizational principle of information is topographical mapping of specific dimensions. Such maps have been shown for sensorimotor information within sensorimotor cortices (e.g., retinotopy). Here we ask whether there are topographic maps – by analogy, contentopic maps – for mid-level object-related dimensions. We used functional magnetic resonance imaging and population receptive field analysis to measure tuning of neural populations to selected manipulable object-related action-based dimensions. We show maps in dorsal and ventral occipital cortex that code for the score of each object on each target dimension in a linear progression following a particular direction along the cortical surface. Maps for each dimension are distinct, are consistent across individuals, and are not exhausted by participant-specific eccentricity maps, nor by high-definition eccentricity maps derived from available databases. Thus, object information is potentially coded in multiple topographical maps – i.e., contentopic maps. These contentopic maps refer to intermediate level visual and visuomotor representations, potentially computed from the interaction of lower-level visual features through non-linear transformation following gestalt principles. This suggests that topography is a widespread and non-incidental strategy for the organization of information in the brain that leads to greatly reduced connectivity-related metabolic costs and fast and efficient readouts of information for stimuli discrimination.