Question

Question 2. Consider the following olfactory learning experiment performed in Drosophila Phase 1: A fly is presented sequentially with 2 odors, odor A and odor B Phase 2: Odor A is presented again along with sugar, while odor B is presented alone Phase 3: Odors A and B are sequentially presented again You conduct this experiment while recording the activity of mushroom body output neurons (MBONs) or dopamine neurons (DANs) from two different mushroom body compartments. Compartment 1 has an MBON that promotes attraction (MBON 1). Compartment 2 has an MBON that promotes aversion (MBON 2). The compartments are innervated by separate DANs, called DAN 1 (innervating compartment 1) or DAN 2 (innervating compartment 2) a. During this experiment, when are DAN 1 and DAN 2 activated (if at all)? b. During Phase 1 of the experiment, which odor(s) do MBON 1 and MBON 2 respond to? For each odor, how do the MBON responses compare (does one MBON respond more strongly than the other)? c. During Phase 3 of the experiment, which odor(s) do MBON 1 and MBON 2 respond to? For each odor, how do the MBON responses compare (does one MBON respond more strongly than the other)? Which responses have changed relative to the responses in Phase 1? Next, you repeat the same experiment while monitoring the activity (depolarization) of the cell bodies of Kenyon cells (KCs). During Phase 1 of the experiment, you observe that some KC cell bodies respond to odor A and others respond to odor B, and their responses have the same magnitude d. If you observe the same cell bodies during Phase 3 of the experiment, how have their odor responses changed from Phase 1 (if at all)? Why? (Suggested: 1-2 sentences)

Answer 1

Eight different kinds of dopamine innervate by the mushroom body. Dopamine responds to the odor and pairing of the odor.

MBON respond to the odor and the rewards associated to it.

a) yes, in this experiment, DAN 1 and DAN 2 will be activated in response to the odor. When MBON gets activated, then its modulatory DAN will also get activated.

b) During phase one, the MBON 1 and 2 both gets activated depending upon the like or dislike of the odor. since odor is new and not learned earlier, both the MBON shows the reading. If each odor is liked by fly then MBON1 strongly respond and iF each odor is disliked, then MBON2 is strongly responded.

c) In phase 3, MBON 1 is strongly responded to odour 1. This is because odor 1 is along with the reward of sugar. While MBON 2 is responded to odour 2 as it has no reward. This happens because in third phase, they are have learned the odor.