Behavioral methods that can test the perceived similarities of different odorants, such as the methods mentioned above, as well as certain others Kay et al. Sign up. Topological defects in flat geometry: the role of density inhomogeneity. In addition to temporal patterns of spiking in individual mitral cells, widespread odorant-evoked oscillatory patterns of a variety of periodicities also have been demonstrated in various olfactory systems Adrian, b ; Freeman and Skarda, ; Freeman and Viana Di Prisco, ; Laurent and Naraghi, ; Gelperin, ; Kay, Rodents probably would have received less benefit from any selective detection of these compounds.
In our experiments, we typically express this relative activity mapa sexta y septima region in Irvine a z score, where the uptake at each location is calculated as the number of standard deviations above or below the mean glomerular layer uptake Johnson et al.
The bars represent the numbers of nipple crystals within different size range bins on the x-axis, with increments of 0. In general, we have found that flexible, straight-chained aliphatic odorants such as valeric acid and methyl valerate are the ones that tend to activate large clusters of glomeruli at high concentrations Figure 3Awhereas odorant molecules with less flexibility fewer rotatable bonds activate fewer glomeruli Johnson et mapa sexta y septima region in Irvine.
Huang, P. It is in the procerebrum where the odor-dependent oscillatory activity of Limax is studied Teyke and Gelperin, ; Gelperin et al. Others using optical imaging methods also have found that different concentrations of an aldehyde can evoke unique relative activity patterns in the dorsal aspect of the bulb Fried et al.
Odorants can differ along many chemical dimensions. Center-surround lateral inhibition can narrow the molecular receptive range of mitral cells within chemotopically arranged glomerular response domains.
These tests would include at least: 1 a search for correlations between similarities in temporal patterns and similarities in perceived odors, and 2 a determination of whether specific interventions with the temporal pattern produce the expected consequences for odor-guided behavior.
Supplementary Information. Although a particular chemical detected in urine activates similar bulbar regions and elicits similar behaviors as urine Lin et al. Early bulbar ablation studies were not guided by a complete knowledge of the activity patterns evoked by the odorants investigated, because these response maps were not available at that time Slotnick et al.
The olfactory system evolved to solve biologically relevant problems under certain constraints, and an all-purpose qualitative analysis of odorant chemistry would not be expected of the system, which is more likely to be focused on sets of odorant chemicals that contribute important information relevant to survival and reproduction.
If the 2DG patterns were relevant to olfactory discrimination, we would predict that a lesion of the differentially activated posterior-ventral glomeruli would decrease the overall pattern differences between the odorants and therefore might make them more difficult to discriminate.