Extracting Behaviorally Relevant Traits from Natural Stimuli: Benefits of Combinatorial Representations at the Accessory Olfactory Bulb
Fig 1
A. The experimental preparation. Stimuli are presented to the VNO through the nostril, and then the sympathetic nerve trunk is stimulated with a cuff electrode to induce VNO suction. Extracellular multi-site probes (32 channels) were targeted to the external cell layer of the AOB. Inset shows a 20μm sagittal section including the main and accessory olfactory bulbs. One tract made by a probe dipped in DiI (red) prior to insertion can be seen. Blue: DAPI nuclear stain. B. Illustration of stimulus sources (secretions) used. C. Datasets used in this study. L,M,H represent stimuli of low, medium and high concentrations (for vaginal secretions: L = 9x dilution, M = 3x, H = 1x, for urine: L = 300x, M = 100x, H = 33x). In stimulus set 3, stimuli were not diluted following collection. D. Outline of the classification approach. Single-trial responses (see rasters for five trials, one of which is highlighted in red) for each unit were defined as the mean firing rate change following stimulus presentation (indicated by bar). Response vectors of all units are then used to train and test specific classifiers. The cartoon networks on the right show classifiers with hypothetical downstream units (blue) receiving inputs from AOB units (gray). The cartoons illustrate that different classifiers may assign different weights to each of the units.