, 2011 and von Philipsborn et al., 2011). Male courtship behavior is influenced by a range of sensory inputs (Krstic et al., 2009 and Koganezawa et al., 2010), especially the olfactory system (Billeter et al., 2009). Photoactivatable GFP

has been used to trace connectivity from the olfactory receptors that detect female flies through the antennal lobe to second order projections (Datta et al., 2008 and Ruta et al., 2010). Anatomical analysis suggests a compartment-level convergence of FruM neurons (Yu et al., 2010) and expression of dendritic Ruxolitinib order and synaptic reporters in candidate partners suggests connectivity (von Philipsborn et al., 2011). New understandings of the neural basis for courtship behavior have been reviewed (Manoli et al., 2006, Dickson, 2008 and Benton,

2011). The courtship circuit has several advantages: a single gene (or isoform) expressed in many neural components, sexually dimorphic anatomy and behavior, some known sensory inputs, and corroborative historical data from gynandromorphs and feminization screens (Hall, 1979, Ferveur et al., 1995 and Broughton et al., 2004), but the astute use of genetic tools to manipulate neurons has led to our current understanding of the neural circuit driving male courtship behavior. Recent work has demonstrated functional imaging of FruM neurons during a facsimile of courtship behavior (Kohatsu et al., 2011), which will allow interrogation of how neurons within the circuit respond to specific sensory stimuli and how their activity correlates with behavioral output. Dasatinib molecular weight The same experimental setup could be used to deliver specific activity patterns with light-stimulated channelrhodopsin to determine how these neurons affect behavioral outcomes. Although

there is still much work to be done to connect the identified components of a courtship circuit and find the not missing links, the potential to understand how a neural circuit actually works to drive this complex behavior is unmatched. Similar smart use of the powerful tools described here should enable mapping of circuits driving a range of different behaviors. This will permit circuit comparisons, identification of neurons that participate in several circuits, and the investigation of the way decisions between behavioral programs are made. To understand how the nervous system of an animal controls a particular behavior, one needs to identify the neurons involved, determine how their activity influences the behavior, and explore how they connect to other participating neurons. The abundance of tools for spatially and temporally targeting gene expression to specific neurons, manipulating or observing their activity, and assaying behavioral consequences makes Drosophila a premier system for exploring the principles guiding the development and function of neural circuits.