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SUMMARY:Mushroom body output neurons encode the valence and guide memory-b
 ased action selection in Drosophila. - Dr Yoshi Aso\, HHMI Janelia Farm
DTSTART:20150703T090000Z
DTEND:20150703T100000Z
UID:TALK60014@talks.cam.ac.uk
CONTACT:Robert Jones
DESCRIPTION:The mushroom body is a center for associative memory in insect
  brains. Sparse activity in the ~2\,000 mushroom body (MB) intrinsic neuro
 ns\, the Kenyon cells\, is thought to represent the identity of environmen
 tal cues such as odors. Distinct dopaminergic neurons innervating the MB c
 onvey information about reward or punishment. The convergence of these inp
 uts allows the MB to adaptively assign valence to sensory stimuli\, permit
 ting an individual fly to appropriately adjust its behavioral response whe
 n it later encounters the same stimulus. MB output neurons (MBONs) are tho
 ught to read and translate the activity of Kenyon cells to bias selection 
 of behavioral responses\, but little is know about how they accomplish thi
 s task. \nWe have described the detailed projection patterns of the 21 typ
 es of MBONs and 20 types of dopaminergic and other modulatory neurons. Eac
 h of the 21 MBON type elaborates segregated dendritic arbors in the MB lob
 es\, forming 15 compartments that collectively tile the lobes. Using inter
 sectional split-GAL4 drivers that allow manipulation of individual cell ty
 pes\, we have begun the process of determining the nature of the informati
 on conveyed by MBONs. We show that optogenetic activation of MBONs can\, d
 epending on the specific cell type\, either repel or attract untrained fli
 es by biasing directional turning. The effects of different MBONs are addi
 tive\, implying that activities of MBONs representing opposing valence are
  balanced in untrained flies. We propose that the ensemble of the MBONs co
 llectively encodes overall valence and changing the balance between MBONs 
 by dopamine modulation biases behavioral responses. Based on this initial 
 work\, we are performing further anatomical and behavioral analyses with t
 he goal of understanding the circuit principles for a system of memory-bas
 ed valuation and action selection. I will present examples from our recent
  unpublished work.
LOCATION:MRC LMB: Klug Seminar Room 2A180
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