Neural correlates of a perspective-taking task using in a realistic 3D environment based task: a pilot functional MRI study
Sri Mahavir Agarwal 1, Venkataram Shivakumar 1, Sunil V Kalmady 1, Vijay Danivas 1, Anekal C Amaresha 1, Anushree Bose 1, Janardhanan C Narayanaswamy 1, Michel-Ange Amorim 2, Ganesan Venkatasubramanian 1*
1NIMHANS, Bangalore, India, 2CIAMS, Univ. Paris-Sud, Université Paris-Saclay, Orsay, France
Received: September 18, 2016; Revised: December 21, 2016; Accepted: January 10, 2017; Published online: January 10, 2017.
© The Korean College of Neuropsychopharmacology. All rights reserved.

Objective: Perspective-taking ability is an essential spatial faculty that is of much interest in both health and neuropsychiatric disorders. There is limited data on the neural correlates of perspective taking in the context of a realistic 3D environment. We report the results of a pilot study exploring the same in eight healthy volunteers.
Methods: Subjects underwent two runs of an experiment in a 3 T MRI involving alternate blocks of a first-person perspective based allocentric object location memory task (OLMT), a third-person perspective based egocentric visual perspective taking task (VPRT), and a table task (TT) that served as a control. Difference in BOLD response during task performance was analyzed using SPM12. Activations were considered significant if they survived family-wise error correction at the cluster level using a height threshold of p<0.001, uncorrected at the voxel level.
Results: A significant difference in accuracy and reaction time based on task type was found. Subjects had significantly lower accuracy in VPRT compared to TT. Accuracy in the two active tasks was not significantly different. Subjects took significantly longer in the VPRT in comparison to TT. Reaction time in the two active tasks was not significantly different. FMRI revealed significantly higher activation in the bilateral visual cortex and left temporoparietal junction (TPJ) in VPRT compared to OLMT.
Conclusion: The results underscore the importance of TPJ in egocentric manipulation in healthy controls in the context of reality-based spatial tasks.
Keywords: egocentric, allocentric, fMRI, temporoparietal junction