This suggests that the piriform cortical ensembles completed the slightly degraded input, and responded as if the entire odor object was present. As more components were removed or novel contaminants added, piriform cortical ensembles decorrelated the mixtures even more strongly than the olfactory bulb (Barnes et al., 2008). Behavioral discrimination performance in a two-alternative choice task mirrored the cortical ensemble decorrelation—mixtures not decorrelated by the cortex were difficult for the animals to discriminate (Barnes et al., this website 2008). These results suggest that, as originally hypothesized (Haberly, 2001), the piriform

cortex can perform pattern completion which contributes to perceptual stability. Interestingly, new data suggest that the boundary between cortical

pattern completion and separation is experience dependent. Cortical pattern completion can be enhanced in tasks requiring odor generalization and pattern separation can be enhanced in tasks requiring fine odor acuity (J. Chapuis and D.A. Wilson, 2010, Soc. Neurosci., abstract). These changes in olfactory cortical processing lead to changes in perceptual acuity in both rodents (J. Chapuis and D.A. Wilson, 2010, Soc. Neurosci., abstract; Chen et al., 2011 and Fletcher and Wilson, 2002) and humans (Li et al., 2008 and Li et al., 2006). An autoexcitatory cortical network such as the piriform www.selleckchem.com/products/z-vad-fmk.html cortex Mephenoxalone is susceptible to run-away excitation and seizure activity. Thus, synaptic inhibition plays an important role in maintaining circuit function within manageable extremes. However, inhibition can also play important roles

in shaping receptive fields of individual neurons, and imposing temporal structure in pyramidal spike trains and circuit oscillations. These factors have been assumed in past cortical models but were never fully developed (Haberly, 2001). We now know that there are a large variety of inhibitory interneurons in piriform cortex falling into perhaps five different classes based on morphology, location, and physiological properties (Suzuki and Bekkers, 2010a, Suzuki and Bekkers, 2010b, Young and Sun, 2009 and Zhang et al., 2006), and these new data suggest unique roles for different cell classes. Interneurons have somata in all three layers of the piriform, and connections that can either remain within the same layer or spread to other layers. In addition to interlaminar connections, the connectivity and function of inhibitory interneurons may also vary over the anterior-posterior extent of the piriform cortex. For example, pyramidal cells in anterior piriform cortex appear to be under stronger inhibitory control from interneurons more caudal to them than interneurons more rostral (Luna and Pettit, 2010).