Figure 8.

A subpopulation of BLA neurons that encoded port entries in the presence of the sucrose reinforcer developed a phasic response to the empty port only during the extinction epoch and predicts response intensity and extinction resistance. A, A representative BLA neuron that was inhibited by port entries when sucrose is present, did not respond to port entries when sucrose was absent during maintenance, but developed a phasic inhibition upon port entries when sucrose was absent during extinction only. B, Population histograms of normalized activity for each port entry condition including the 22 neurons that displayed a similar response profile to that of the representative neuron in A. C, A representative BLA neuron that was excited by port entries when sucrose is present, did not respond upon port entries when sucrose was absent during maintenance, but was inhibited by port entries when sucrose was absent during extinction. D, Population histograms showing normalized activity in each port entry condition for neurons with response profiles such as the neurons shown in C. E, The proportion of neurons in the “reinforcement-omission” population recorded per rat was significantly correlated with each rat's response intensity (E) and extinction resistance (F).