, 2012). Briefly, adult male (>P60) C57BL/6Crl mice were anesthetized with isoflurane,

a craniotomy (∼2 mm in diameter) made over left barrel cortex, and the dura left intact. The genetically encoded Ca2+ indicator GCaMP3 expressed under the human synapsin-1 promoter following infection with recombinant adenoassociated virus (serotype 2/1; produced by the University of Pennsylvania Gene Therapy Program Vector Core) was injected stereotaxically to deep layers of the primary vibrissae barrel somatosensory neocortex. The craniotomy was covered with a half-moon-shaped double-layered glass coverslip, a small portion (∼0.7 mm in diameter) of the craniotomy was left open and filled with high throughput screening compounds silicon gel to allow pharmacological manipulation. A titanium head-post was attached to the skull. Fourteen days after virus injection and window implantation, mice began training on the go/no-go tactile detection task (Xu et al., 2012). Briefly, a vertical pole (the target object) was presented to the right side of the mouse face either within reach by the whiskers in “go” trials (licking leads to water reward) or out of reach in “no-go” trials (licking leads to timeout without water). Selleck Bcl 2 inhibitor Mice determined the location of the object using active whisking and object contact in order to respond with lick in go trials and hold licking

in no-go trials. The behavioral apparatus was mounted under a custom two-photon

microscope equipped with a high-speed whisker imaging system. Apical dendritic tuft activity was imaged from GCaMP3-positive apical dendrites of layer five second pyramidal neurons at depths of 20–400 μm (Xu et al., 2012). Image analysis was performed as described (Xu et al., 2012). To estimate the amplitude and frequency of individual Ca2+ transients, we measured the peak ΔF/F of detected Ca2+ events. Event detection was based on combined thresholding of the amplitude (>4 SD, estimated using median absolute deviation) and rising slope (computed from a span of three frames) of ΔF/F time series from all trials of a given ROI. We thank A. Milstein and M. Roberts for help in creating analysis tools. This work was supported by the Australian Research Council (FT100100502), the National Health and Medical Research Council (APP1004575), and the Howard Hughes Medical Institute. “
“Tobacco (nicotine) and alcohol are the two most abused and costly drugs to society. Epidemiological studies consistently find a positive correlation between nicotine and alcohol use, with alcoholism approximately ten times more prevalent in smokers than in nonsmokers (DiFranza and Guerrera, 1990, Harrison et al., 2008, McKee et al., 2007, Schorling et al., 1994 and Weitzman and Chen, 2005). Several studies also show that nicotine exposure increases alcohol self-administration (Barrett et al., 2006, Lê et al., 2003 and Smith et al.