Control of Escape Behavior by Descending Neurons in Drosophila Melanogaster /

Saved in:
Bibliographic Details
Author / Creator:Peek, Martin Y., author.
Imprint:2018.
Ann Arbor : ProQuest Dissertations & Theses, 2018
Description:1 electronic resource (144 pages)
Language:English
Format: E-Resource Dissertations
Local Note:School code: 0330
URL for this record:http://pi.lib.uchicago.edu/1001/cat/bib/11781892
Hidden Bibliographic Details
Other authors / contributors:University of Chicago. degree granting institution.
ISBN:9780438756861
Notes:Advisors: Gwyneth M. Card Committee members: Melina Hale; Ellie Heckscher; Daniel Margoliash.
Dissertation Abstracts International, Volume: 80-05(E), Section: B.
English
Summary:To avoid predation, nervous systems detect looming motion cues from a predator's approach to generate evasive responses . Looming-sensitive visual neurons and escape-evoking giant neurons have been identified in mobile species across the animal kingdom (Eaton, 1984). In flies, escape is composed of a sequence of movements to initiate flight: freezing, postural adjustment, wing elevation and wing depression with leg extension. These sub-behaviors determine critical properties of the escape. Postural shifts determine escape direction (Card, 2008b). The giant fiber (GF) neuron's role in leg extension and wing depression for rapid takeoff has been well-characterized (Vonreyn, 2014), indicating that additional, unknown descending neurons must contribute to the control of the other sub-behaviors in the sequence. In this study, we characterize a group of eight descending neurons (LC4DNs) which may control escape by serving as parallel signaling pathways, connecting the same regions in the brain and ventral nerve cord (VNC) as the GF. Specifically, this group of neurons extends dendrites to an optic glomerulus formed by the axon terminals of a looming-sensitive (Vonreyn, 2017) visual projection neuron cell type called lobula columnar type 4 (LC4) (Namiki, 2018). In behavioral experiments, optogenetic activation of cell type-specific lines shows that select LC4DNs can evoke long-mode escapes, distinct from the GF-driven short-mode escapes. Whole-cell patch clamp recordings a subset of LC4DNs demonstrates similar looming-sensitivity and speed tuning, as would be expected from a common looming-sensitive input, like LC4. Finer analysis of LC4DN-activation reveals induced postural shifts that control escape direction, comparable to looming-evoked behavior. DNp11 activation generated forward jumps, whereas DNp02 and DNp04 co-activation induced backwards jumps. To determine a sensory input basis for directionality, we analyzed synaptic connectivity in an electron microscopy dataset (Zheng, 2018) to find inequalities in the number of synaptic connections between LC4 neurons and LC4DNs. Visualization of the LC4 dendrites reveals spatial gradients that are in opposite polarity to the activation-induced jump direction. These findings suggest a rapid feed-forward control mechanism by LC4DNs in which looming features are encoded by LC4 neurons and then filtered through a synaptic gradient that determines spatial selectivity of those features in specific DNs such that the fly generates postural shifts for escape away from the looming location.
LEADER 04602ntm a22003973i 4500
001 11781892
005 20190205151407.5
007 cr un|---|||||
008 190205s2018 miu|||||om |||||||eng d
003 ICU
020 |a 9780438756861 
035 |a (MiAaPQD)AAI10977993 
035 |a (MiAaPQD)uchicago:14623 
040 |a MiAaPQD  |b eng  |c MiAaPQD  |e rda 
100 1 |a Peek, Martin Y.,  |e author. 
245 1 0 |a Control of Escape Behavior by Descending Neurons in Drosophila Melanogaster /  |c Martin Y Peek. 
260 |c 2018. 
264 1 |a Ann Arbor :   |b ProQuest Dissertations & Theses,   |c 2018 
300 |a 1 electronic resource (144 pages) 
336 |a text  |b txt  |2 rdacontent  |0 http://id.loc.gov/vocabulary/contentTypes/txt 
337 |a computer  |b c  |2 rdamedia  |0 http://id.loc.gov/vocabulary/mediaTypes/c 
338 |a online resource  |b cr  |2 rdacarrier  |0 http://id.loc.gov/vocabulary/carriers/cr 
500 |a Advisors: Gwyneth M. Card Committee members: Melina Hale; Ellie Heckscher; Daniel Margoliash. 
502 |b Ph.D.  |c University of Chicago, Division of the Biological Sciences, Department of Organismal Biology and Anatomy  |d 2018. 
510 4 |a Dissertation Abstracts International,   |c Volume: 80-05(E), Section: B. 
520 |a To avoid predation, nervous systems detect looming motion cues from a predator's approach to generate evasive responses . Looming-sensitive visual neurons and escape-evoking giant neurons have been identified in mobile species across the animal kingdom (Eaton, 1984). In flies, escape is composed of a sequence of movements to initiate flight: freezing, postural adjustment, wing elevation and wing depression with leg extension. These sub-behaviors determine critical properties of the escape. Postural shifts determine escape direction (Card, 2008b). The giant fiber (GF) neuron's role in leg extension and wing depression for rapid takeoff has been well-characterized (Vonreyn, 2014), indicating that additional, unknown descending neurons must contribute to the control of the other sub-behaviors in the sequence. In this study, we characterize a group of eight descending neurons (LC4DNs) which may control escape by serving as parallel signaling pathways, connecting the same regions in the brain and ventral nerve cord (VNC) as the GF. Specifically, this group of neurons extends dendrites to an optic glomerulus formed by the axon terminals of a looming-sensitive (Vonreyn, 2017) visual projection neuron cell type called lobula columnar type 4 (LC4) (Namiki, 2018). In behavioral experiments, optogenetic activation of cell type-specific lines shows that select LC4DNs can evoke long-mode escapes, distinct from the GF-driven short-mode escapes. Whole-cell patch clamp recordings a subset of LC4DNs demonstrates similar looming-sensitivity and speed tuning, as would be expected from a common looming-sensitive input, like LC4. Finer analysis of LC4DN-activation reveals induced postural shifts that control escape direction, comparable to looming-evoked behavior. DNp11 activation generated forward jumps, whereas DNp02 and DNp04 co-activation induced backwards jumps. To determine a sensory input basis for directionality, we analyzed synaptic connectivity in an electron microscopy dataset (Zheng, 2018) to find inequalities in the number of synaptic connections between LC4 neurons and LC4DNs. Visualization of the LC4 dendrites reveals spatial gradients that are in opposite polarity to the activation-induced jump direction. These findings suggest a rapid feed-forward control mechanism by LC4DNs in which looming features are encoded by LC4 neurons and then filtered through a synaptic gradient that determines spatial selectivity of those features in specific DNs such that the fly generates postural shifts for escape away from the looming location. 
546 |a English 
590 |a School code: 0330 
690 |a Neurosciences. 
710 2 |a University of Chicago.  |e degree granting institution.  |0 http://id.loc.gov/authorities/names/n79058404 
720 1 |a Gwyneth M. Card  |e degree supervisor. 
856 4 0 |u http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqm&rft_dat=xri:pqdiss:10977993  |y ProQuest 
903 |a HeVa 
929 |a eresource 
999 f f |i 42a37dc2-d72a-5811-81a4-1823f4647578  |s 3b0b1b39-4d2e-56e6-a0ab-8d376df5698d 
928 |t Library of Congress classification  |l Online  |c UC-FullText  |u http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqm&rft_dat=xri:pqdiss:10977993  |z ProQuest  |g ebooks  |i 11234146