Figure 2.
mPFC Encodes Expectation of Negative Outcomes. (A) Pain-associated foci in human mPFC from a meta-analysis of 192 neuroimaging studies. Top panel: locations of individual activated foci associated with delivery of physically painful stimuli, such as heat, cold or electric shock. Bottom panel: thresholded activation likelihood estimate (Shackman et al., 2011). (B) Changes in blood flow in the rat brain during exposure to an environment previously associated with painful colorectal distention. Cerebral blood flow was imaged via radioactively labeled [14C]-iodoantipyrine. Colors indicate statistically significant differences between conditioned and control rats in positive (red) and negative (blue) directions (Wang et al., 2011). Abbreviations: fmi – forceps minor of the corpus callosum, S1, S2 – primary and secondary somatosensory cortex. (C) Development of shock-anticipatory activity in mPFC during trace eye-blink conditioning. In Box A, rats were exposed to a tone as a conditioned stimulus (CS) and, after a 500 ms delay, mild eye-shock as an unconditioned stimulus (US). In Box B, CS and US were presented randomly so that the tone was not predictive of shock (pseudo-conditioning). Within each of the two sub-plot on the left, each row shows a z-score value for averaged population activity from all neurons showing an excitatory response during CS and trace interval. The horizontal axis indicates time within a trial and spans 1800 milliseconds. Early in training (rows below “Early”), mPFC cells respond primarily during the tone. After successful acquisition (rows above “Late”), cells maintain responses throughout the delay until delivery of shock. No such shock-anticipatory activity is evident in pseudo-conditioned Box B. The two panels on the right show similar results for all neurons showing an inhibitory response during the CS and trace interval (Takehara-Nishiuchi and McNaughton, 2008).