People always concern about what they have and what they might lose even it is just imaginary property. According to Prospect Theory, the losses might be weighted by subjects higher than gain, which would cause the disparity between the willingness to accept (WTA) and willingness to pay (WTP) compensation in economic valuation. Using functional MRI, we investigated neural correlates of this inconsistent value estimation, known as the endowment effect, during a simple pricing task without economic transaction Brain activation associated with this price discrepancy was observed in the right inferior frontal gyrus (IFG). where voxel-based morphometry of MRI revealed the positive correlation between gray matter concentration and WTA/WTP ratio These findings suggest the functional relevance of IFG in WTA/WTP discrepancy for pricing without any actual gain and loss, where an integration of loss aversion-related signals from insula and expected value signals may occur. (C) 2010 Elsevier Ireland Ltd and the Japan Neuroscience Society All rights reserved.