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Neuron hemilineages provide the functional ground plan for the Drosophila ventral nervous system.

Harris RM, Pfeiffer BD, Rubin GM, Truman JW - Elife (2015)

Bottom Line: The next level was hemilineages of similar projection cells that drove intersegmentally coordinated behaviors such as walking.The highest level involved hemilineages whose activation elicited complex behaviors such as takeoff.These activation phenotypes indicate that the hemilineages vary in their behavioral roles with some contributing to local networks for sensorimotor processing and others having higher order functions of coordinating these local networks into complex behavior.

View Article: PubMed Central - PubMed

Affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.

ABSTRACT
Drosophila central neurons arise from neuroblasts that generate neurons in a pair-wise fashion, with the two daughters providing the basis for distinct A and B hemilineage groups. 33 postembryonically-born hemilineages contribute over 90% of the neurons in each thoracic hemisegment. We devised genetic approaches to define the anatomy of most of these hemilineages and to assessed their functional roles using the heat-sensitive channel dTRPA1. The simplest hemilineages contained local interneurons and their activation caused tonic or phasic leg movements lacking interlimb coordination. The next level was hemilineages of similar projection cells that drove intersegmentally coordinated behaviors such as walking. The highest level involved hemilineages whose activation elicited complex behaviors such as takeoff. These activation phenotypes indicate that the hemilineages vary in their behavioral roles with some contributing to local networks for sensorimotor processing and others having higher order functions of coordinating these local networks into complex behavior.

No MeSH data available.


Related in: MedlinePlus

Dorsal (A) and transverse (B) view of the T2 region of the adult VNS showing a lineage 19 MARCM clone.The 19A siblings project ventrally into the ipsilateral leg neuropil while the 19B siblings project across the posterior commissure (white arrowhead). (C, D) Z-projections of ventral (C) and dorsal (D) regions of the clone that captures most of the arbors of the 19A and 19B hemilineages, respectively. The 19A cells have primarily arbor in their leg neuropil but they also have a prominent projection to the midline. The 19B cells have strong lateral anterior projections (lat) that are both ipsilateral and contralateral as well as weaker, symmetrical medial projections (med).DOI:http://dx.doi.org/10.7554/eLife.04493.029
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fig7s1: Dorsal (A) and transverse (B) view of the T2 region of the adult VNS showing a lineage 19 MARCM clone.The 19A siblings project ventrally into the ipsilateral leg neuropil while the 19B siblings project across the posterior commissure (white arrowhead). (C, D) Z-projections of ventral (C) and dorsal (D) regions of the clone that captures most of the arbors of the 19A and 19B hemilineages, respectively. The 19A cells have primarily arbor in their leg neuropil but they also have a prominent projection to the midline. The 19B cells have strong lateral anterior projections (lat) that are both ipsilateral and contralateral as well as weaker, symmetrical medial projections (med).DOI:http://dx.doi.org/10.7554/eLife.04493.029

Mentions: In the larva, the lineage 19 cluster is situated dorsolaterally at the posterior border of each thoracic neuromere. The 19A neurons descend into the ipsilateral leg neuropil, while the 19B neurons project across the iP commissure and turn anteriorly. The adult morphology is similar. The 19A and 19B cell clusters remain in the posteriodorsal region of each segment. The 19A neurons project into the ipsilateral leg neuropil, where they form a major projection extending through lateral and ventral leg neuropil and a medial projection that extends to the midline. The medial projections in T1 and T2 converge on the midline in T2 (Figure 7F,G). nSyt::GFP localizes to the most medial (distal) part of the medial projection (Figure 7H). The hemilineage 19B cluster in T1 is greatly reduced in the larva, and after metamorphosis the 19B cluster in T3 is also very small, presumably through cell death during metamorphosis. The adult T2 neurons make a robust projection across the iP commissure and arborize dorsally in the tectulum neuropil. The 19B neurons have both medial and lateral arbors that project anteriorly (Figure 7J,K; Figure 7—figure supplement 1).


Neuron hemilineages provide the functional ground plan for the Drosophila ventral nervous system.

Harris RM, Pfeiffer BD, Rubin GM, Truman JW - Elife (2015)

Dorsal (A) and transverse (B) view of the T2 region of the adult VNS showing a lineage 19 MARCM clone.The 19A siblings project ventrally into the ipsilateral leg neuropil while the 19B siblings project across the posterior commissure (white arrowhead). (C, D) Z-projections of ventral (C) and dorsal (D) regions of the clone that captures most of the arbors of the 19A and 19B hemilineages, respectively. The 19A cells have primarily arbor in their leg neuropil but they also have a prominent projection to the midline. The 19B cells have strong lateral anterior projections (lat) that are both ipsilateral and contralateral as well as weaker, symmetrical medial projections (med).DOI:http://dx.doi.org/10.7554/eLife.04493.029
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Related In: Results  -  Collection

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fig7s1: Dorsal (A) and transverse (B) view of the T2 region of the adult VNS showing a lineage 19 MARCM clone.The 19A siblings project ventrally into the ipsilateral leg neuropil while the 19B siblings project across the posterior commissure (white arrowhead). (C, D) Z-projections of ventral (C) and dorsal (D) regions of the clone that captures most of the arbors of the 19A and 19B hemilineages, respectively. The 19A cells have primarily arbor in their leg neuropil but they also have a prominent projection to the midline. The 19B cells have strong lateral anterior projections (lat) that are both ipsilateral and contralateral as well as weaker, symmetrical medial projections (med).DOI:http://dx.doi.org/10.7554/eLife.04493.029
Mentions: In the larva, the lineage 19 cluster is situated dorsolaterally at the posterior border of each thoracic neuromere. The 19A neurons descend into the ipsilateral leg neuropil, while the 19B neurons project across the iP commissure and turn anteriorly. The adult morphology is similar. The 19A and 19B cell clusters remain in the posteriodorsal region of each segment. The 19A neurons project into the ipsilateral leg neuropil, where they form a major projection extending through lateral and ventral leg neuropil and a medial projection that extends to the midline. The medial projections in T1 and T2 converge on the midline in T2 (Figure 7F,G). nSyt::GFP localizes to the most medial (distal) part of the medial projection (Figure 7H). The hemilineage 19B cluster in T1 is greatly reduced in the larva, and after metamorphosis the 19B cluster in T3 is also very small, presumably through cell death during metamorphosis. The adult T2 neurons make a robust projection across the iP commissure and arborize dorsally in the tectulum neuropil. The 19B neurons have both medial and lateral arbors that project anteriorly (Figure 7J,K; Figure 7—figure supplement 1).

Bottom Line: The next level was hemilineages of similar projection cells that drove intersegmentally coordinated behaviors such as walking.The highest level involved hemilineages whose activation elicited complex behaviors such as takeoff.These activation phenotypes indicate that the hemilineages vary in their behavioral roles with some contributing to local networks for sensorimotor processing and others having higher order functions of coordinating these local networks into complex behavior.

View Article: PubMed Central - PubMed

Affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.

ABSTRACT
Drosophila central neurons arise from neuroblasts that generate neurons in a pair-wise fashion, with the two daughters providing the basis for distinct A and B hemilineage groups. 33 postembryonically-born hemilineages contribute over 90% of the neurons in each thoracic hemisegment. We devised genetic approaches to define the anatomy of most of these hemilineages and to assessed their functional roles using the heat-sensitive channel dTRPA1. The simplest hemilineages contained local interneurons and their activation caused tonic or phasic leg movements lacking interlimb coordination. The next level was hemilineages of similar projection cells that drove intersegmentally coordinated behaviors such as walking. The highest level involved hemilineages whose activation elicited complex behaviors such as takeoff. These activation phenotypes indicate that the hemilineages vary in their behavioral roles with some contributing to local networks for sensorimotor processing and others having higher order functions of coordinating these local networks into complex behavior.

No MeSH data available.


Related in: MedlinePlus