Abstract
Do neural representations in the visual cortex change from childhood to adulthood? Unlike associative cortex, the structure and functional organization of visual cortex is thought to mature relatively early in life. However, it is unknown whether the representation of information in visual cortex changes with development. Given ongoing development of association cortex—prefrontal and parietal regions in particular—it is possible that children’s visual cortex might be less modulated by the top-down signals coming from these regions. If so, it is possible that children’s visual cortex represents more task-irrelevant information as compared with adult visual cortex.
In the present study, we ask how top-down signals modulate neural representations in children’s visual cortex. We measured brain activity using fMRI while adults (21-31 years) and children (7-10 years) were performing a one-back working memory task in which they were directed to attend to either motion or an object present in a complex display where both objects and motion were present. To examine how these features are represented in children’s and adults’ visual cortices, we used multivoxel pattern analysis and compared decoding accuracy of task-relevant and task-irrelevant features. In adults’ visual cortex, we found higher decoding accuracy for task-relevant features (i.e. motion direction in the motion-attended condition) compared to those for task-irrelevant features (i.e. objects in the motion-attended condition). However, in children’s visual cortex, both task-relevant and task-irrelevant features were decoded equally well. These findings show that the developing visual cortex might represent more information than the adult visual cortex, which is known to prioritize task-related information. Also, this research suggests that unlike the structural properties, the functional properties of visual cortex continue to develop into late childhood.