Neural activity in human visual cortex is transformed by learning real world size

Abstract

The way that our brain processes visual information is directly affected by our experience. Repeated exposure to a visual stimulus triggers experience-dependent plasticity in the visual cortex of many species. Humans also have the unique ability to acquire visual knowledge through instruction. We introduced human participants to the real-world size of previously unfamiliar species, and to the functional motion of novel tools, during a functional magnetic resonance imaging scan. Using machine learning, we compared activity patterns evoked by images of the new items, before and after participants learned the animals' real-world size or tools' motion. We found that, after acquiring size information, participants' visual activity patterns became more confusable between novel and same-sized animals in early visual cortex, but not in ventral temporal cortex, reflecting an influence of new size knowledge on posterior, but not anterior, components of the ventral stream. In contrast, learning the functional motion of new tools did not lead to an equivalent change in recorded activity. Finally, the time-points marked by evidence of new size information in early visual cortex were more likely to show size information and greater activation in the right angular gyrus, a key hub of semantic knowledge and spatial cognition. Overall, these findings suggest that learning an item's real-world size by instruction influences subsequent activity in visual cortex and in a region that is central to semantic and spatial brain systems.

The link between conceptual and perceptual information in memory

“…Further, real-world size is detectable in early visual cortex, even when the common correlation between size and taxonomic category is removed (Coutanche & Koch, 2018). In a design that draws on a learning intervention, we have found that declaratively learning a novel item's real-world size can lead to changes in activity patterns in early visual cortex (Coutanche & Thompson-Schill, 2019). While being scanned with functional magnetic resonance imaging (fMRI), these participants viewed images of previously unfamiliar (and familiar) species, before and after learning the unfamiliar animals' real-world size through on-screen text.…”

Real-world size of objects serves as an axis of object space

“…Therefore, although a real car and a toy car share similar visual appearances, actions on these two objects are completely different ( 8 ). Further, the feature of objects’ real-world size also provides important information for high-level cognitive processes, such as attention ( 33 ), numerical perceptions ( 34 ), and semantic knowledge ( 35 ). In short, our finding that the feature of objects’ real-world size served as an axis of object space thus may greatly expand our understanding of object recognition from the angle of vision for perception to a novel viewpoint of vision for action.…”

Real-world size of objects serves as an axis of object space

“…Therefore, although a real car and a toy car share similar visual appearances, actions on these two objects are completely different 5 . Further, the feature of objects' real-world size also provides important information for highlevel cognitive processes, such as attention 31 , numerical perceptions 32 , and semantic knowledge 33 . In short, our finding that the feature of objects' real-world size served as an axis of object space thus may greatly expand our understanding of object recognition from the angle of vision for perception to a novel viewpoint of vision for action.…”