Figure 7.

Effects of dopamine receptor blockade on NAshell neuronal activity patterns during nicotine aversion conditioning. (a) Pretreatment with α-flupenthixol (α-flu; 0.8 mg/kg; i.p.) has no significant effect on the spontaneous activity levels of NAshell medium spiny neurons (MSNs). However, MSNs show increased activity during the first, second, and fourth nicotine conditioning trials. Total average MSN neuronal activity patterns did not differ across the different conditioning environments, independently of drug treatment (far right side). (b) In contrast, α-flu pre-treatment causes a significant attenuation in the spontaneous activity levels of NAshell fast-spiking interneurons (FSIs). During conditioning, FSIs show decreased activity (relative to vehicle) during the first, second, and third nicotine conditioning trials. Total average FSI neuronal activity patterns did not differ across the different conditioning environments, independently of drug treatment (far right side). (c) Representative MSN/FSI neuronal rastergram overlay showing 10 min pre intra-ventral tegmental area nicotine (0.008 nmol/0.5 μl) vs post-activity levels with characteristic increased spontaneous MSN vs decreased FSI firing rates in the presence of α-flu. *p<0.05; **p<0.01. NA shell, shell region of the NAc; N.S., not significant.