FIGURE 1

FIGURE 1

Organization of the olfactory bulb network. Odorants are detected in the olfactory epithelium by three types of sensory neurons (microvillous, ciliated, and crypt cells) that project to different glomeruli located in different areas of the olfactory bulb. Ciliated cells mainly project to the dorsal and medial olfactory bulb; microvillous cells project to the lateral olfactory bulb (Sato et al., 2005, 2007). Crypt cells project to a dorsomedial domain in zebrafish and to a ventral domain in carp (Hamdani el and Doving, 2006; Gayoso et al., 2012). In each glomerulus, olfactory sensory neuron axons contact dendrites of mitral cells, the output cells of the olfactory bulb. Inhibitory interneurons called granules cells are located in the deepest layer of the bulb and modulate the activity of mitral cells. Solid lines represent connections described in zebrafish. Dotted lines represent connections described in other fish species. OE: olfactory epithelium, OB: olfactory bulb, ON: olfactory nerve, POFL: primary olfactory fiber layer, GL: glomerular layer, ECL: external cell layer, ICL: internal cell layer.