RT Journal Article
SR Electronic
T1 Functional and Anatomical Specificity in a Higher Olfactory Centre
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 336982
DO 10.1101/336982
A1 Shahar Frechter
A1 Alexander S. Bates
A1 Sina Tootoonian
A1 Michael-John Dolan
A1 James D. Manton
A1 Arian Jamasb
A1 Johannes Kohl
A1 Davi Bock
A1 Gregory S. X. E. Jefferis
YR 2018
UL http://biorxiv.org/content/early/2018/12/21/336982.abstract
AB Most sensory systems are organized into parallel neuronal pathways that process distinct aspects of incoming stimuli. For example, in insects, second order olfactory projection neurons target both the mushroom body, which is required for learning, and the lateral horn (LH), which has been proposed to mediate innate olfactory behavior. Mushroom body neurons encode odors in a sparse population code, which does not appear stereotyped across animals. In contrast the functional principles of odor coding in the LH remain poorly understood. We have carried out a comprehensive anatomical analysis of the Drosophila LH, counting ~1400 neurons; combining genetic driver lines, anatomical and functional criteria, we identify 165 LHN cell types. We then show that genetically labeled LHNs have stereotyped odor responses across animals for 33 of these cell types. LHN tuning can be ultra-sparse (1/40 odors tested), but on average single LHNs respond to three times more odors than single projection neurons. This difference can be rationalized by our observation that LHNs are better odor categorizers, likely due to pooling of input projection neurons responding to different odors of the same category. Our results reveal some of the principles by which a higher sensory processing area can extract innate behavioral significance from sensory stimuli.