Abstract
Recent eye-tracking, self-paced reading, and neuroimaging studies suggest that tracking multiple representations of the same object as it undergoes a state-change engenders conflict due to having to distinguish the ‘before’ and ‘after’ states of the object (Altmann and Kamide, 2009; Hindy et al., under review). We use fMRI and multi-voxel pattern analysis to test the degree to which an object state-change causes a distinct neural representation of the same object. We varied whether an object was minimally changed by a described action (e.g., "weigh the pumpkin") or substantially changed by the action (e.g., "carve the pumpkin"), and measured the neural similarity between imagined visual representations of that object before and after the action. Each experiment trial began with a briefly presented object photograph, followed by a sequence of three visual imagery task instructions separated by fixation: imagine the object, then imagine a specified action that involves the object, and finally imagine the object in its final state after the action. Subsequent to the three visual imagery segments, a retrieval cue instructed participants to indicate which of two clipart images is most similar to the object at either the beginning or end of the trial. In object-selective regions of ventral temporal and lateral occipital cortex, we find that the multi-voxel pattern similarity across time points before and after the described action was significantly reduced when the object was substantially changed, compared to when the object was minimally changed. Furthermore, this neural similarity between the ‘before’ and ‘after’ brain states varied parametrically with the rated degree to which the object was changed in state by the described action. Results suggest that, when representing object state-change, a distinct representation of the same object is instantiated in the ventral visual processing pathway, even though the distinct representation is not the result of visual processing.
Meeting abstract presented at VSS 2012