Functional Imaging of Conceptual Representations

A concept is a mental representation that encompasses multiple aspects of an item, but what is the neurological substrate of this representation? One hypothesis states that such representations depend upon multimodal binding processes within a single region. Convergent evidence suggests that such a region may exist within the temporal lobe(see Patterson 2007). To test these hypotheses we utilized two established paradigms, behavioral priming and physiological suppression, to examine response to the repetition of concepts across perceptual modalities. Typically, examinations of the relationship between behavioral priming and suppression have queried the extent to which suppression effects in different brain regions correlate with single measures of behavioral priming. In contrast, we were interested in the extent to which suppression effects within a single brain region would correlate with multiple measures of behavioral priming. While many sensory regions show suppression effects to specific perceptual repetitions, we hypothesized that a region engaged in conceptual representation would show suppression effects to conceptual repetitions, even when the stimuli were perceptually distinct. Using BOLD (Blood Oxygenation Level Dependent) data, we determined that suppression effects in perirhinal cortex, a temporal lobe region, significantly correlate with behavioral priming in a multimodal manner. This result provides evidence that perirhinal cortex is engaged in conceptual representation.