Economic risk can be defined as statistical variance: larger variance indicates more risk (mean-preserving spread; Rothschild & Stiglitz 1970). Some neurons in orbitofrontal cortex signal this form of risk but do not signal reward value. View the report here (O'Neill & Schultz 2010).

Risk prediction error is defined as the difference between predicted risk and current risk (here: risk defined by variance, no skewness). Here we present the neuronal coding of unsigned risk prediction error in OFC. View the report here (O'Neill & Schultz 2013).