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. 2012 Feb 22;32(8):2886–2899. doi: 10.1523/JNEUROSCI.5625-11.2012

Figure 2.

Figure 2.

Disconnection of the BLA–NAc pathway reduces choice of the Large/Risky option, but does not affect reward magnitude discrimination. A, Percentage choice of the Large/Risky lever following disconnection of the NAc and BLA and control treatments across four blocks of free-choice trials. Symbols represent mean, error bars are SEM. Black star denotes p < 0.05 for the average choice from ipsilateral/disconnection versus saline. Inset shows data from a subset of rats that did not show a decrease in risky choice after ipsilateral inactivation (n = 7), yet still showed a decrease in risky choice following functional disconnection (star denotes p < 0.05). B, Schematic of sections of the rat brain showing location of acceptable infusions in the NAc and BLA for rats in discounting (circles) and magnitude discrimination (squares) experiments. Numbers correspond to millimeters from bregma. Figure represents the disconnection procedure for clarity; hemispheres of infusions were counterbalanced across rats. C, Win–stay/lose–shift ratios following saline infusions, ipsilateral, and functional disconnection (asymmetrical inactivation) of the BLA–NAc pathway. Win–stay values are displayed as the proportion of choices on the Large/Risky lever following a rewarded risky choice on the preceding trial. Lose–shift values are displayed as the proportion of choices on the Small/Certain lever following unrewarded risky choice on the preceding trial. Neither of these measures were significantly altered by BLA–NAc disconnections. D, Disrupting communication in this pathway had no effect on preference for larger versus smaller rewards on a simpler reward magnitude discrimination. Inset shows response latencies to press the large or small reward lever on forced choice trials after saline infusions for rats trained on the reward magnitude discrimination or the probabilistic discounting task. Rats trained on the latter showed a smaller difference between latencies to press the larger versus smaller reward lever compared with those trained on the simpler magnitude discrimination (star denotes p < 0.01).