Relapse from nicotine abstinence increases the pacemaking frequency of cholinergic habenular neurons

The discovery of genetic variants in the CHRNA5-CHRNA3-CHRNB4 gene cluster associated with heavy smoking and higher relapse risk has led to the identification of the midbrain habenula- interpeduncular axis as a critical relay circuit in the control of nicotine addiction Here we profile the cholinergic neurons of the medial habenula and identify the unique transcirptional features of this population of neurons. For each cell population, three independent TRAP replicates were collected, and total RNA from both the immunoprecipitate and unbound fractions were seperately amplified and hybridized. For each tissue, several representative unnbound fractions are provided to serve as controls. Biological replicates are GCRMA normalized within groups. Following averaging of replicates, we recommend further global normalization between groups, using affymetrix biotinylated controls, to correct for any broad biases in scanning and hybridization. Finally for many analyses, we also recommend filtering to remove those probesets with low IP/UB fold change values from each cell type(see PMID:20962086). Researchers can contact us for spreadsheets where these additional steps have been completed.