RT Journal Article
SR Electronic
T1 Functional Organization of the Parahippocampal Cortex: Dissociable Roles for Context Representations and the Perception of Visual Scenes
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 2536
OP 2542
DO 10.1523/JNEUROSCI.3368-15.2016
VO 36
IS 8
A1 Oliver Baumann
A1 Jason B. Mattingley
YR 2016
UL http://www.jneurosci.org/content/36/8/2536.abstract
AB The human parahippocampal cortex has been ascribed central roles in both visuospatial and mnemonic processes. More specifically, evidence suggests that the parahippocampal cortex subserves both the perceptual analysis of scene layouts as well as the retrieval of associative contextual memories. It remains unclear, however, whether these two functional roles can be dissociated within the parahippocampal cortex anatomically. Here, we provide evidence for a dissociation between neural activation patterns associated with visuospatial analysis of scenes and contextual mnemonic processing along the parahippocampal longitudinal axis. We used fMRI to measure parahippocampal responses while participants engaged in a task that required them to judge the contextual relatedness of scene and object pairs, which were presented either as words or pictures. Results from combined factorial and conjunction analyses indicated that the posterior section of parahippocampal cortex is driven predominantly by judgments associated with pictorial scene analysis, whereas its anterior section is more active during contextual judgments regardless of stimulus category (scenes vs objects) or modality (word vs picture). Activation maxima associated with visuospatial and mnemonic processes were spatially segregated, providing support for the existence of functionally distinct subregions along the parahippocampal longitudinal axis and suggesting that, in humans, the parahippocampal cortex serves as a functional interface between perception and memory systems.SIGNIFICANCE STATEMENT The functional neuroanatomy of the parahippocampal cortex is still subject to considerable debate. Specifically, its relative contributions to visuospatial and mnemonic functions remain unclear. This study constitutes the first evidence for the existence of distinct information-processing properties along the parahippocampal longitudinal axis. Our findings implicate the posterior section of the parahippocampus in visuospatial perception and the anterior section in contextual mnemonic processes. Our study provides novel neuroanatomical information critical for understanding the diversity of the purported functions of the human parahippocampal cortex.