In summary, the studies by Chen et al. (2012) and van Versendaal et al. (2012) convincingly show that inhibitory synapses in the adult brain display profound structural dynamics

of their own. By means of the tracking of individual postsynaptic inhibitory synaptic scaffolds in vivo they were able to reveal that L2/3 cell ocular dominance plasticity may be initiated by the pruning of predominantly inhibitory spine synapses on apical dendrites. This pruning occurs close to dynamic spines and may regulate plasticity of circuits that preferentially impinge on distal dendrites. These studies firmly establish that inhibitory structural remodeling has its share in visual cortex plasticity and provide a framework for future endeavors to unravel its mechanisms. “
“In the 1998 film The Truman Show, a group of television producers labors with Herculean selleck chemicals passion to manufacture an artificial but believable world for an insurance PI3K Inhibitor Library nmr salesman, Truman Burbank (played by actor Jim Carrey), who unwittingly stars in his own reality show. As each new day dawns, or is meant to dawn, in the town of Seahaven, the order is shouted within the TV control room to “cue the sun!” The well-timed appearance of a heavenly orb—perhaps the most reliable and dependable sensory cue known to roosters and humans alike—signals morning and launches Truman out of bed. Hollywood actors notwithstanding, human and nonhuman animals

of all sorts readily utilize sensory cues to predict events and guide behavior. External cues, typically arriving in visual, olfactory, auditory, or verbal format, may announce a general state-based change in behavior or in the environmental milieu, for example, the sound of a dinner bell signaling that food is imminent. Alternatively, external cues may forecast more specific information about the identity of an upcoming event, enhancing sensory discrimination, response speed, and perceptually based decisions. The roasted smell of coffee in the morning sets up an expectation of coffee flavor that is met upon sipping from your breakfast mug. Not infrequently, an

external cue can be uninformative or misinformative, or absent altogether. Having learned to predict the through presence of something that is actually not there has adverse behavioral consequences, reducing discrimination and response speed, and creating cognitive dissonance. Finding that the same coffee smell leads not to coffee but, unexpectedly, to black tea (sipping from the wrong mug, for example) may result in breakfast dismay. The majority of neuroscientific research on sensory expectation, awareness, and prediction has focused on the visual system (Gilbert and Sigman, 2007, Kouider and Dehaene, 2007 and Summerfield and Egner, 2009), whereas comparable studies of the chemical senses—smell and taste—are, well, to be unexpected. In this issue of Neuron, Samuelsen et al.