Fig. 1
From: Functional architecture of reward learning in mushroom body extrinsic neurons of larval Drosophila
Overview of anatomical relationships, and of the requirement of MBINs and MBONs across behavioral tasks. a Body plan of stage 3 Drosophila larvae102 (modified with permission from ref. 102); brain refers to the ventral nerve cord plus the two brain hemispheres toward the left. Also see Supplementary Movies 1-5. b Simplified diagram of the olfactory and gustatory pathways, and of the organization of innate and learned olfactory behavior, as well as of innate gustatory behavior in the larva. AL antennal lobe, KC Kenyon cells of the mushroom body, LH lateral horn, MBIN mushroom body input neurons, MBON mushroom body output neurons, OSN olfactory sensory neurons, PN olfactory projection neurons. The red triangles indicate KC output synapses that are modulated by the joint presentation of odor and fructose; gray and black triangles indicate silent and active synapses, respectively. The gray boxes indicate mushroom body compartments. The integral sign implies that learned odor valence can be based on an integration of MBON activity from multiple compartments. Circuitry within the AL and the APL neuron are not displayed. Also, circuit motifs newly discovered7, namely KC-KC connections as well as KC > DAN and MBIN > MBON connections, are not included. c Schematic of the location and orientation of the mushroom body within the larval nervous system. The mushroom body is only shown in one hemisphere. A anterior, D dorsal, P posterior, L lateral, M medial, V ventral. d Organization of the larval mushroom body in 11 compartments. CX calyx; IP and LP intermediate and lower peduncle; LA lateral appendix; UVL, IVL, and LVL upper, intermediate, and lower vertical lobe; SHA, UT, IT, LT shaft as well as upper, intermediate, and lower toe of the medial lobe. Single-letter synonyms of compartment names are given as “a–k”; these letters are used to indicate compartment innervation by the MBEs in Fig. 2. e Summary of the requirement of MBINs, MBONs, and of the APL neuron across behavioral tasks, based on the data shown in Figs. 2–4, and Supplementary Table 1
