Different influences of visual associative memory on the neural activity in the human ventral occipital cortex

Specific responses in the fusiform face area (FFA) and the parahippocampal place area (PPA) presumably underlie visual object recognition, with the relative strength of neural activity coding for the object class. However, the issue of whether these areas rest on fundamentally distinct computational processes is an unexplored area. In this study, we examined whether object-class specificity is modifiable by the long-term learning of tasks that involve faces or buildings. The experiment consisted of four fMRI sessions over eight weeks. Eleven participants were involved in two novel tasks in which faces were arbitrarily associated with two-dimensional coordinates, and buildings were associated with architectural styles. As the learning progressed, BOLD responses at the FFA significantly decreased in the associative learning tasks regardless of the object class, while no such change was observed for brain activity at the PPA. These findings suggest that the FFA plays a role in visual associative memory. As the associations grow more efficient as the result of repeated experience, the neural activity required for retrieval may decrease in strength and/or in duration, leading to less BOLD activation.