Jump to content

Drosophila connectome: Difference between revisions

Add links
From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
→Adult ventral nerve cord: Male nerve cord released in 2023.
Citation bot (talk | contribs)
Bots
5,370,750 edits
Alter: pages, template type. Add: pmc, display-authors, s2cid, doi, authors 1-30. Formatted dashes. | Use this bot. Report bugs. | #UCB_CommandLine
Line 1: Line 1:
The '''Drosophila connectome''' is the complete list of connections between [[neuron]]s (commonly referred to as the "[[connectome]]") in the ''[[Drosophila melanogaster]]'' (fruit fly) nervous system. The ''Drosophila'' connectome has been completed for the female adult brain,<ref name="Dorkenwald_2023">{{cite biorxiv | vauthors = Dorkenwald S, Matsliah A, Sterling AR, Schlegel P, Yu SC, McKellar CE, Lin A, Costa M, Eichler K, Yin Y, Silversmith W, Schneider-Mizell C, Jordan CS, Brittain D, Halageri A, Kuehner K, Ogedengbe O, Morey R, Gager J, Kruk K, Perlman E, Yang R, Deutsch D, Bland D, Sorek M, Lu R, Macrina T, Lee K, Bae JA, Mu S, Nehoran B, Mitchell E, Popovych S, Wu J, Jia Z, Castro M, Kemnitz N, Ih D, Bates AS, Eckstein N, Funke J, Collman F, Bock DD, Jefferis GS, Seung HS, Murthy M | display-authors = 6 | title = Neuronal wiring diagram of an adult brain | date = June 2023 | biorxiv = 10.1101/2023.06.27.546656 }}</ref>{{Unreliable source?|sure=y|reason=Not peer reviewed|date=July 2023}} the male nerve cord,<ref>{{Cite biorxiv | vauthors = Takemura SY, Hayworth KJ, Huang GB, Januszewski M, Lu Z, Marin EC, Preibisch S, Xu CS, Bogovic J, Champion AS, Cheong HS | date = June 2023 | display-authors = 6 |biorxiv = 10.1101/2023.06.05.543757 |title=A Connectome of the Male Drosophila Ventral Nerve Cord}}</ref>{{Unreliable source?|sure=y|reason=Not peer reviewed|date=July 2023}} and the larval stage.<ref name = "Winding_2023" /> The female fruit fly brain contains 127,978 <!-- 135,000 must be old estimate (for male only?). "~130,000 neurons" for the female, is most recent number for the paper, show it or the precise number from the YouTube video from the researchers? Possibly, and likely the number isn't the same for both sexes, nor the same for each individual of either sex? In some species e.g. C. elegans the number is constant, I doubt for a fly, but I don't know if it's known either way. --> [[neuron]]s (for the first adult neuronal wiring diagram), and 3,016 neurons for the larval brain.So the synapse count is available for adults and larvae, and <!-- show here adult count, since it for "chemical synapses", is that a synonym synapses, I want to show comparable numbers, if not skip here? --> for the larvae it's the much lower number of roughly 548,000. The connectome is the most complex full one yet mapped, before mapped for only three other simpler organisms, first the ''[[Caenorhabditis elegans|C. elegans]]''. The connectomes have been obtained by the methods of [[neural circuit reconstruction]]; <!-- "(EM) brain images. In recent years, this approach has been applied to chunks of brains to reconstruct local connectivity maps that are highly informative, yet inadequate for understanding brain function more globally." A stack of EM images of an entire brain exist, suitable for sparse tracing of specific circuits. --> Many of the 76 compartments of the ''Drosophila'' brain had connectomes available before the publication of the full connectome.
The '''Drosophila connectome''' is the complete list of connections between [[neuron]]s (commonly referred to as the "[[connectome]]") in the ''[[Drosophila melanogaster]]'' (fruit fly) nervous system. The ''Drosophila'' connectome has been completed for the female adult brain,<ref name="Dorkenwald_2023">{{cite bioRxiv | vauthors = Dorkenwald S, Matsliah A, Sterling AR, Schlegel P, Yu SC, McKellar CE, Lin A, Costa M, Eichler K, Yin Y, Silversmith W, Schneider-Mizell C, Jordan CS, Brittain D, Halageri A, Kuehner K, Ogedengbe O, Morey R, Gager J, Kruk K, Perlman E, Yang R, Deutsch D, Bland D, Sorek M, Lu R, Macrina T, Lee K, Bae JA, Mu S, Nehoran B, Mitchell E, Popovych S, Wu J, Jia Z, Castro M, Kemnitz N, Ih D, Bates AS, Eckstein N, Funke J, Collman F, Bock DD, Jefferis GS, Seung HS, Murthy M | display-authors = 6 | title = Neuronal wiring diagram of an adult brain | date = June 2023 | biorxiv = 10.1101/2023.06.27.546656 }}</ref>{{Unreliable source?|sure=y|reason=Not peer reviewed|date=July 2023}} the male nerve cord,<ref>{{Cite bioRxiv | vauthors = Takemura SY, Hayworth KJ, Huang GB, Januszewski M, Lu Z, Marin EC, Preibisch S, Xu CS, Bogovic J, Champion AS, Cheong HS | date = June 2023 | display-authors = 6 |biorxiv = 10.1101/2023.06.05.543757 |title=A Connectome of the Male Drosophila Ventral Nerve Cord}}</ref>{{Unreliable source?|sure=y|reason=Not peer reviewed|date=July 2023}} and the larval stage.<ref name = "Winding_2023" /> The female fruit fly brain contains 127,978 <!-- 135,000 must be old estimate (for male only?). "~130,000 neurons" for the female, is most recent number for the paper, show it or the precise number from the YouTube video from the researchers? Possibly, and likely the number isn't the same for both sexes, nor the same for each individual of either sex? In some species e.g. C. elegans the number is constant, I doubt for a fly, but I don't know if it's known either way. --> [[neuron]]s (for the first adult neuronal wiring diagram), and 3,016 neurons for the larval brain.So the synapse count is available for adults and larvae, and <!-- show here adult count, since it for "chemical synapses", is that a synonym synapses, I want to show comparable numbers, if not skip here? --> for the larvae it's the much lower number of roughly 548,000. The connectome is the most complex full one yet mapped, before mapped for only three other simpler organisms, first the ''[[Caenorhabditis elegans|C. elegans]]''. The connectomes have been obtained by the methods of [[neural circuit reconstruction]]; <!-- "(EM) brain images. In recent years, this approach has been applied to chunks of brains to reconstruct local connectivity maps that are highly informative, yet inadequate for understanding brain function more globally." A stack of EM images of an entire brain exist, suitable for sparse tracing of specific circuits. --> Many of the 76 compartments of the ''Drosophila'' brain had connectomes available before the publication of the full connectome.


== Why ''Drosophila'' ==
== Why ''Drosophila'' ==
Line 5: Line 5:
* The brain contains about 135,000 neurons,<ref>
* The brain contains about 135,000 neurons,<ref>
{{cite journal | vauthors = Alivisatos AP, Chun M, Church GM, Greenspan RJ, Roukes ML, Yuste R | title = The brain activity map project and the challenge of functional connectomics | journal = Neuron | volume = 74 | issue = 6 | pages = 970–974 | date = June 2012 | pmid = 22726828 | pmc = 3597383 | doi = 10.1016/j.neuron.2012.06.006 }}</ref> small enough to be currently reconstructed .<ref>
{{cite journal | vauthors = Alivisatos AP, Chun M, Church GM, Greenspan RJ, Roukes ML, Yuste R | title = The brain activity map project and the challenge of functional connectomics | journal = Neuron | volume = 74 | issue = 6 | pages = 970–974 | date = June 2012 | pmid = 22726828 | pmc = 3597383 | doi = 10.1016/j.neuron.2012.06.006 }}</ref> small enough to be currently reconstructed .<ref>
{{cite journal | vauthors = DeWeerdt S | title = How to map the brain | journal = Nature | volume = 571 | issue = 7766 | pages = S6-S8 | date = July 2019 | pmid = 31341309 | doi = 10.1038/d41586-019-02208-0 | doi-access = free | bibcode = 2019Natur.571S...6D }}</ref>
{{cite journal | vauthors = DeWeerdt S | title = How to map the brain | journal = Nature | volume = 571 | issue = 7766 | pages = S6–S8 | date = July 2019 | pmid = 31341309 | doi = 10.1038/d41586-019-02208-0 | doi-access = free | bibcode = 2019Natur.571S...6D }}</ref>
* The fruit fly exhibits many complex behaviors. Hundreds of different behaviors (feeding, grooming, flying, mating, learning, and so on) have been qualitatively and quantitatively studied over the years.
* The fruit fly exhibits many complex behaviors. Hundreds of different behaviors (feeding, grooming, flying, mating, learning, and so on) have been qualitatively and quantitatively studied over the years.
* The [[Drosophila genome|genetics of the fruit fly]] are well understood, and many (tens of thousands) of genetic variants are available.
* The [[Drosophila genome|genetics of the fruit fly]] are well understood, and many (tens of thousands) of genetic variants are available.
Line 30: Line 30:


=== Adult ventral nerve cord ===
=== Adult ventral nerve cord ===
In 2022, a group of scientists mapped the motor control circuits of the ventral nerve cord of a female fruit fly using electron microscopy.<ref>{{cite journal | vauthors = Phelps JS, Hildebrand DG, Graham BJ, Kuan AT, Thomas LA, Nguyen TM, Buhmann J, Azevedo AW, Sustar A, Agrawal S, Liu M, Shanny BL, Funke J, Tuthill JC, Lee WA | display-authors = 6 | title = Reconstruction of motor control circuits in adult Drosophila using automated transmission electron microscopy | language = English | journal = Cell | volume = 184 | issue = 3 | pages = 759–774.e18 | date = February 2021 | pmid = 33400916 | pmc = 8312698 | doi = 10.1016/j.cell.2020.12.013 }}</ref> In 2023, a dense reconstruction of the male fly ventral nerve chord was released<ref>{{cite web |url=https://www.biorxiv.org/content/10.1101/2023.06.05.543757v1 |title=A Connectome of the Male Drosophila Ventral Nerve Cord |date=5 Jun 2023 |publisher=bioRxiv}}</ref>.
In 2022, a group of scientists mapped the motor control circuits of the ventral nerve cord of a female fruit fly using electron microscopy.<ref>{{cite journal | vauthors = Phelps JS, Hildebrand DG, Graham BJ, Kuan AT, Thomas LA, Nguyen TM, Buhmann J, Azevedo AW, Sustar A, Agrawal S, Liu M, Shanny BL, Funke J, Tuthill JC, Lee WA | display-authors = 6 | title = Reconstruction of motor control circuits in adult Drosophila using automated transmission electron microscopy | language = English | journal = Cell | volume = 184 | issue = 3 | pages = 759–774.e18 | date = February 2021 | pmid = 33400916 | pmc = 8312698 | doi = 10.1016/j.cell.2020.12.013 }}</ref> In 2023, a dense reconstruction of the male fly ventral nerve chord was released<ref>{{cite journal |url=https://www.biorxiv.org/content/10.1101/2023.06.05.543757v1 |title=A Connectome of the Male Drosophila Ventral Nerve Cord |date=5 Jun 2023 |publisher=bioRxiv|doi=10.1101/2023.06.05.543757 |last1=Takemura |first1=Shin-ya |last2=Hayworth |first2=Kenneth J. |last3=Huang |first3=Gary B. |last4=Januszewski |first4=Michal |last5=Lu |first5=Zhiyuan |last6=Marin |first6=Elizabeth C. |last7=Preibisch |first7=Stephan |last8=Xu |first8=C Shan |last9=Bogovic |first9=John |last10=Champion |first10=Andrew S. |last11=Cheong |first11=Han SJ |last12=Costa |first12=Marta |last13=Eichler |first13=Katharina |last14=Katz |first14=William |last15=Knecht |first15=Christopher |last16=Li |first16=Feng |last17=Morris |first17=Billy J. |last18=Ordish |first18=Christopher |last19=Rivlin |first19=Patricia K. |last20=Schlegel |first20=Philipp |last21=Shinomiya |first21=Kazunori |last22=Stürner |first22=Tomke |last23=Zhao |first23=Ting |last24=Badalamente |first24=Griffin |last25=Bailey |first25=Dennis |last26=Brooks |first26=Paul |last27=Canino |first27=Brandon S. |last28=Clements |first28=Jody |last29=Cook |first29=Michael |last30=Duclos |first30=Octave |s2cid=259120564 |display-authors=1 }}</ref>.


=== Larval brain ===
=== Larval brain ===
In 2023, Michael Winding et al. published a complete larval brain connectome.<ref>{{cite web | vauthors = Leffer L |title=First Complete Map of a Fly Brain Has Uncanny Similarities to AI Neural Networks |url=https://gizmodo.com/first-complete-map-fly-brain-neuroscience-1850206820 |access-date=10 March 2023 |website=Gizmodo}}</ref><ref name = "Winding_2023">{{cite journal | vauthors = Winding M, Pedigo BD, Barnes CL, Patsolic HG, Park Y, Kazimiers T, Fushiki A, Andrade IV, Khandelwal A, Valdes-Aleman J, Li F, Randel N, Barsotti E, Correia A, Fetter RD, Hartenstein V, Priebe CE, Vogelstein JT, Cardona A, Zlatic M | display-authors = 6 | title = The connectome of an insect brain | journal = Science | volume = 379 | issue = 6636 | pages = eadd9330 | date = March 2023 | pmid = 36893230 | doi = 10.1126/science.add9330 }}</ref> This connectome was mapped by annotating the previously collected electron microscopy volume.<ref>{{cite journal | vauthors = Ohyama T, Schneider-Mizell CM, Fetter RD, Aleman JV, Franconville R, Rivera-Alba M, Mensh BD, Branson KM, Simpson JH, Truman JW, Cardona A, Zlatic M | display-authors = 6 | title = A multilevel multimodal circuit enhances action selection in Drosophila | journal = Nature | volume = 520 | issue = 7549 | pages = 633–639 | date = April 2015 | pmid = 25896325 | doi = 10.1038/nature14297 }}</ref> They found that the larval brain was composed of 3,016 neurons and 548,000 synapses. 93% of brain neurons had a homolog in the opposite hemisphere. Of the synapses, 66.6% were axo-dendritic, 25.8% were axo-axonic, 5.8% were dendro-dendritic, and 1.8% were dendro-axonic.
In 2023, Michael Winding et al. published a complete larval brain connectome.<ref>{{cite web | vauthors = Leffer L |title=First Complete Map of a Fly Brain Has Uncanny Similarities to AI Neural Networks |url=https://gizmodo.com/first-complete-map-fly-brain-neuroscience-1850206820 |access-date=10 March 2023 |website=Gizmodo}}</ref><ref name = "Winding_2023">{{cite journal | vauthors = Winding M, Pedigo BD, Barnes CL, Patsolic HG, Park Y, Kazimiers T, Fushiki A, Andrade IV, Khandelwal A, Valdes-Aleman J, Li F, Randel N, Barsotti E, Correia A, Fetter RD, Hartenstein V, Priebe CE, Vogelstein JT, Cardona A, Zlatic M | display-authors = 6 | title = The connectome of an insect brain | journal = Science | volume = 379 | issue = 6636 | pages = eadd9330 | date = March 2023 | pmid = 36893230 | doi = 10.1126/science.add9330 | pmc = 7614541 }}</ref> This connectome was mapped by annotating the previously collected electron microscopy volume.<ref>{{cite journal | vauthors = Ohyama T, Schneider-Mizell CM, Fetter RD, Aleman JV, Franconville R, Rivera-Alba M, Mensh BD, Branson KM, Simpson JH, Truman JW, Cardona A, Zlatic M | display-authors = 6 | title = A multilevel multimodal circuit enhances action selection in Drosophila | journal = Nature | volume = 520 | issue = 7549 | pages = 633–639 | date = April 2015 | pmid = 25896325 | doi = 10.1038/nature14297 | s2cid = 4464547 }}</ref> They found that the larval brain was composed of 3,016 neurons and 548,000 synapses. 93% of brain neurons had a homolog in the opposite hemisphere. Of the synapses, 66.6% were axo-dendritic, 25.8% were axo-axonic, 5.8% were dendro-dendritic, and 1.8% were dendro-axonic.


To study the connectome, they treated it as a directed graph with the neurons forming nodes and the synapses forming the edges. Using this representation, Winding et al found that the larval brain neurons could be clustered into 93 different types, based on connectivity alone. These types aligned with the known neural groups including [[Sensory neuron|sensory neurons]] (visual, olfactory, gustatory, thermal, etc), [[Descending neuron|descending neurons]], and [[ascending neurons]].
To study the connectome, they treated it as a directed graph with the neurons forming nodes and the synapses forming the edges. Using this representation, Winding et al found that the larval brain neurons could be clustered into 93 different types, based on connectivity alone. These types aligned with the known neural groups including [[Sensory neuron|sensory neurons]] (visual, olfactory, gustatory, thermal, etc), [[Descending neuron|descending neurons]], and [[ascending neurons]].
Line 40: Line 40:


== Structure and behavior ==
== Structure and behavior ==
A natural question is whether the connectome will allow simulation of the fly's behavior. However, the connectome alone is not sufficient. Additional information needed includes [[gap junction]] varieties and locations, identities of [[neurotransmitters]], [[Receptor (biochemistry) | receptor]] types and locations, [[neuromodulators]] and [[hormones]] (with sources and receptors), the role of [[glial cells]], [[Synapse#Role_in_memory | time evolution rules]] for synapses, and more.<ref>{{cite web |url= http://www.bionet.ee.columbia.edu/workshops/bcmc/2019 | title = Columbia Workshop on Brain Circuits, Memory and Computation | work = Center for Neural Engineering and Computation | publisher = Columbia University | location = New York, NY | date = March 2019 }}</ref><ref>{{cite journal | vauthors = Scheffer LK, Meinertzhagen IA | title = A connectome is not enough - what is still needed to understand the brain of Drosophila? | journal = The Journal of Experimental Biology | volume = 224 | issue = 21 | pages = jeb242740 | date = November 2021 | pmid = 34695211 | doi = 10.1242/jeb.242740 }}</ref>
A natural question is whether the connectome will allow simulation of the fly's behavior. However, the connectome alone is not sufficient. Additional information needed includes [[gap junction]] varieties and locations, identities of [[neurotransmitters]], [[Receptor (biochemistry) | receptor]] types and locations, [[neuromodulators]] and [[hormones]] (with sources and receptors), the role of [[glial cells]], [[Synapse#Role_in_memory | time evolution rules]] for synapses, and more.<ref>{{cite web |url= http://www.bionet.ee.columbia.edu/workshops/bcmc/2019 | title = Columbia Workshop on Brain Circuits, Memory and Computation | work = Center for Neural Engineering and Computation | publisher = Columbia University | location = New York, NY | date = March 2019 }}</ref><ref>{{cite journal | vauthors = Scheffer LK, Meinertzhagen IA | title = A connectome is not enough - what is still needed to understand the brain of Drosophila? | journal = The Journal of Experimental Biology | volume = 224 | issue = 21 | pages = jeb242740 | date = November 2021 | pmid = 34695211 | doi = 10.1242/jeb.242740 | s2cid = 239887246 }}</ref>


The fruit fly connectome has been used to identify an area of the fruit fly brain that is involved in odor detection and tracking. Flies choose a direction in turbulent conditions by combining information about the direction of air flow and the movement of odor packets. Based on the fly connectome, processing must occur in the “fan-shaped body” where wind-sensing neurons and olfactory direction-sensing neurons cross.<ref name="Mackenzie_2023">{{cite journal | vauthors = Mackenzie D |title=How animals follow their nose |journal=Knowable Magazine |publisher=Annual Reviews |date=6 March 2023 |doi=10.1146/knowable-030623-4 |doi-access=free |url=https://knowablemagazine.org/article/living-world/2023/how-animals-follow-their-nose |access-date=13 March 2023 |language=en}}</ref><ref name="Matheson_2022">{{cite journal | vauthors = Matheson AM, Lanz AJ, Medina AM, Licata AM, Currier TA, Syed MH, Nagel KI | title = A neural circuit for wind-guided olfactory navigation | journal = Nature Communications | volume = 13 | issue = 1 | pages = 4613 | date = August 2022 | pmid = 35941114 | doi = 10.1038/s41467-022-32247-7 }}</ref>
The fruit fly connectome has been used to identify an area of the fruit fly brain that is involved in odor detection and tracking. Flies choose a direction in turbulent conditions by combining information about the direction of air flow and the movement of odor packets. Based on the fly connectome, processing must occur in the “fan-shaped body” where wind-sensing neurons and olfactory direction-sensing neurons cross.<ref name="Mackenzie_2023">{{cite journal | vauthors = Mackenzie D |title=How animals follow their nose |journal=Knowable Magazine |publisher=Annual Reviews |date=6 March 2023 |doi=10.1146/knowable-030623-4 |doi-access=free |url=https://knowablemagazine.org/article/living-world/2023/how-animals-follow-their-nose |access-date=13 March 2023 |language=en}}</ref><ref name="Matheson_2022">{{cite journal | vauthors = Matheson AM, Lanz AJ, Medina AM, Licata AM, Currier TA, Syed MH, Nagel KI | title = A neural circuit for wind-guided olfactory navigation | journal = Nature Communications | volume = 13 | issue = 1 | pages = 4613 | date = August 2022 | pmid = 35941114 | doi = 10.1038/s41467-022-32247-7 | pmc = 9360402 }}</ref>


== See also ==
== See also ==

Revision as of 00:51, 25 July 2023

The Drosophila connectome is the complete list of connections between neurons (commonly referred to as the "connectome") in the Drosophila melanogaster (fruit fly) nervous system. The Drosophila connectome has been completed for the female adult brain,[1][unreliable source] the male nerve cord,[2][unreliable source] and the larval stage.[3] The female fruit fly brain contains 127,978 neurons (for the first adult neuronal wiring diagram), and 3,016 neurons for the larval brain.So the synapse count is available for adults and larvae, and for the larvae it's the much lower number of roughly 548,000. The connectome is the most complex full one yet mapped, before mapped for only three other simpler organisms, first the C. elegans. The connectomes have been obtained by the methods of neural circuit reconstruction; Many of the 76 compartments of the Drosophila brain had connectomes available before the publication of the full connectome.

Why Drosophila

Connectome research (connectomics) has a number of competing objectives. On the one hand, investigators prefer an organism small enough that the connectome can be obtained in a reasonable amount of time. This argues for a small creature. On the other hand, one of the main uses of a connectome is to relate structure and behavior, so an animal with a large behavioral repertoire is desirable. It's also very helpful to use an animal with a large existing community of experimentalists, and many available genetic tools. Drosophila looks very good on these counts:

  • The brain contains about 135,000 neurons,[4] small enough to be currently reconstructed .[5]
  • The fruit fly exhibits many complex behaviors. Hundreds of different behaviors (feeding, grooming, flying, mating, learning, and so on) have been qualitatively and quantitatively studied over the years.
  • The genetics of the fruit fly are well understood, and many (tens of thousands) of genetic variants are available.
  • There are many electrophysiological, calcium imaging, and other studies ongoing with Drosophila.

Structure of the fly connectome

Adult brain

In 2023, the full connectome (for a female) was published: "we present the first neuronal wiring diagram of a whole adult brain, containing 5x10^7 chemical synapses between ~130,000 neurons reconstructed from a female Drosophila melanogaster. [..] The technologies and open ecosystem of the FlyWire Consortium set the stage for future large-scale connectome projects in other species."[1] A projectome, a map of projections between regions, can be derived from the connectome.

Before in 2011, a high-level connectome, at the level of brain compartments and interconnecting tracts of neurons, for the full fly brain was published.[6] A version of this is available online.[7]

Detailed circuit-level connectomes exist for the lamina[8][9] and a medulla[10] column, both in the visual system of the fruit fly, and the alpha lobe of the mushroom body.[11]

In May of 2017 a paper published in bioRxiv presented an electron microscopy image stack of the whole adult female brain at synaptic resolution. The volume is available for sparse tracing of selected circuits.[12][13]

In 2020, a dense connectome of half the central brain of Drosophila was released,[14] along with a web site that allows queries and exploration of this data.[15] The methods used in reconstruction and initial analysis of the connectome followed.[16]

Adult ventral nerve cord

In 2022, a group of scientists mapped the motor control circuits of the ventral nerve cord of a female fruit fly using electron microscopy.[17] In 2023, a dense reconstruction of the male fly ventral nerve chord was released[18].

Larval brain

In 2023, Michael Winding et al. published a complete larval brain connectome.[19][3] This connectome was mapped by annotating the previously collected electron microscopy volume.[20] They found that the larval brain was composed of 3,016 neurons and 548,000 synapses. 93% of brain neurons had a homolog in the opposite hemisphere. Of the synapses, 66.6% were axo-dendritic, 25.8% were axo-axonic, 5.8% were dendro-dendritic, and 1.8% were dendro-axonic.

To study the connectome, they treated it as a directed graph with the neurons forming nodes and the synapses forming the edges. Using this representation, Winding et al found that the larval brain neurons could be clustered into 93 different types, based on connectivity alone. These types aligned with the known neural groups including sensory neurons (visual, olfactory, gustatory, thermal, etc), descending neurons, and ascending neurons.

The authors ordered these neuron types based on proximity to brain inputs vs brain outputs. Using this ordering, they could quantify the proportion of recurrent connections, as the set of connections going from neurons closer to outputs towards inputs. They found that 41% of all brain neurons formed a recurrent connection. The neuron types with the most recurrent connections were the dopaminergic neurons (57%), mushroom body feedback neurons (51%), mushroom body output neurons (45%), and convergence neurons (42%) (receiving input from mushroom body and lateral horn regions). These neurons, implicated in learning, memory, and action-selection, form a set of recurrent loops.

Structure and behavior

A natural question is whether the connectome will allow simulation of the fly's behavior. However, the connectome alone is not sufficient. Additional information needed includes gap junction varieties and locations, identities of neurotransmitters, receptor types and locations, neuromodulators and hormones (with sources and receptors), the role of glial cells, time evolution rules for synapses, and more.[21][22]

The fruit fly connectome has been used to identify an area of the fruit fly brain that is involved in odor detection and tracking. Flies choose a direction in turbulent conditions by combining information about the direction of air flow and the movement of odor packets. Based on the fly connectome, processing must occur in the “fan-shaped body” where wind-sensing neurons and olfactory direction-sensing neurons cross.[23][24]

See also

References

  1. ^ a b Dorkenwald S, Matsliah A, Sterling AR, Schlegel P, Yu SC, McKellar CE, et al. (June 2023). "Neuronal wiring diagram of an adult brain". bioRxiv 10.1101/2023.06.27.546656.
  2. ^ Takemura SY, Hayworth KJ, Huang GB, Januszewski M, Lu Z, Marin EC, et al. (June 2023). "A Connectome of the Male Drosophila Ventral Nerve Cord". bioRxiv 10.1101/2023.06.05.543757.
  3. ^ a b Winding M, Pedigo BD, Barnes CL, Patsolic HG, Park Y, Kazimiers T, et al. (March 2023). "The connectome of an insect brain". Science. 379 (6636): eadd9330. doi:10.1126/science.add9330. PMC 7614541. PMID 36893230.
  4. ^ Alivisatos AP, Chun M, Church GM, Greenspan RJ, Roukes ML, Yuste R (June 2012). "The brain activity map project and the challenge of functional connectomics". Neuron. 74 (6): 970–974. doi:10.1016/j.neuron.2012.06.006. PMC 3597383. PMID 22726828.
  5. ^ DeWeerdt S (July 2019). "How to map the brain". Nature. 571 (7766): S6–S8. Bibcode:2019Natur.571S...6D. doi:10.1038/d41586-019-02208-0. PMID 31341309.
  6. ^ Chiang AS, Lin CY, Chuang CC, Chang HM, Hsieh CH, Yeh CW, et al. (January 2011). "Three-dimensional reconstruction of brain-wide wiring networks in Drosophila at single-cell resolution". Current Biology. 21 (1): 1–11. doi:10.1016/j.cub.2010.11.056. PMID 21129968. S2CID 17155338.
  7. ^ "FlyCircuit - A Database of Drosophila Brain Neurons". National Center for High-Performance Computing (NCHC). Retrieved 30 Aug 2013.
  8. ^ Meinertzhagen IA, O'Neil SD (March 1991). "Synaptic organization of columnar elements in the lamina of the wild type in Drosophila melanogaster". The Journal of Comparative Neurology. 305 (2): 232–263. doi:10.1002/cne.903050206. PMID 1902848. S2CID 35301798.
  9. ^ Rivera-Alba M, Vitaladevuni SN, Mishchenko Y, Lu Z, Takemura SY, Scheffer L, et al. (December 2011). "Wiring economy and volume exclusion determine neuronal placement in the Drosophila brain". Current Biology. 21 (23): 2000–2005. doi:10.1016/j.cub.2011.10.022. PMC 3244492. PMID 22119527.
  10. ^ Takemura SY, Bharioke A, Lu Z, Nern A, Vitaladevuni S, Rivlin PK, et al. (August 2013). "A visual motion detection circuit suggested by Drosophila connectomics". Nature. 500 (7461): 175–181. Bibcode:2013Natur.500..175T. doi:10.1038/nature12450. PMC 3799980. PMID 23925240.
  11. ^ Takemura SY, Aso Y, Hige T, Wong A, Lu Z, Xu CS, et al. (July 2017). "A connectome of a learning and memory center in the adult Drosophila brain". eLife. 6: e26975. doi:10.7554/eLife.26975. PMC 5550281. PMID 28718765.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  12. ^ Yeager A (31 May 2017). "Entire Fruit Fly Brain Imaged with Electron Microscopy". The Scientist Magazine. Retrieved 2018-07-15.
  13. ^ Zheng Z, Lauritzen JS, Perlman E, Robinson CG, Nichols M, Milkie D, et al. (July 2018). "A Complete Electron Microscopy Volume of the Brain of Adult Drosophila melanogaster". Cell. 174 (3): 730–743.e22. doi:10.1016/j.cell.2018.06.019. PMC 6063995. PMID 30033368.
  14. ^ Xu CS, Januszewski M, Lu Z, Takemura SY, Hayworth KJ, Huang G, et al. (2020). "A connectome of the adult Drosophila central brain". bioRxiv 10.1101/2020.01.21.911859.
  15. ^ "Analysis tools for connectomics". Howard Hughes Medical Institute (HHMI).
  16. ^ Scheffer LK, Xu CS, Januszewski M, Lu Z, Takemura SY, Hayworth KJ, et al. (September 2020). "A connectome and analysis of the adult Drosophila central brain". eLife. 9. doi:10.7554/eLife.57443. PMC 7546738. PMID 32880371.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  17. ^ Phelps JS, Hildebrand DG, Graham BJ, Kuan AT, Thomas LA, Nguyen TM, et al. (February 2021). "Reconstruction of motor control circuits in adult Drosophila using automated transmission electron microscopy". Cell. 184 (3): 759–774.e18. doi:10.1016/j.cell.2020.12.013. PMC 8312698. PMID 33400916.
  18. ^ Takemura, Shin-ya; et al. (5 Jun 2023). "A Connectome of the Male Drosophila Ventral Nerve Cord". bioRxiv. doi:10.1101/2023.06.05.543757. S2CID 259120564. {{cite journal}}: Cite journal requires |journal= (help)
  19. ^ Leffer L. "First Complete Map of a Fly Brain Has Uncanny Similarities to AI Neural Networks". Gizmodo. Retrieved 10 March 2023.
  20. ^ Ohyama T, Schneider-Mizell CM, Fetter RD, Aleman JV, Franconville R, Rivera-Alba M, et al. (April 2015). "A multilevel multimodal circuit enhances action selection in Drosophila". Nature. 520 (7549): 633–639. doi:10.1038/nature14297. PMID 25896325. S2CID 4464547.
  21. ^ "Columbia Workshop on Brain Circuits, Memory and Computation". Center for Neural Engineering and Computation. New York, NY: Columbia University. March 2019.
  22. ^ Scheffer LK, Meinertzhagen IA (November 2021). "A connectome is not enough - what is still needed to understand the brain of Drosophila?". The Journal of Experimental Biology. 224 (21): jeb242740. doi:10.1242/jeb.242740. PMID 34695211. S2CID 239887246.
  23. ^ Mackenzie D (6 March 2023). "How animals follow their nose". Knowable Magazine. Annual Reviews. doi:10.1146/knowable-030623-4. Retrieved 13 March 2023.
  24. ^ Matheson AM, Lanz AJ, Medina AM, Licata AM, Currier TA, Syed MH, Nagel KI (August 2022). "A neural circuit for wind-guided olfactory navigation". Nature Communications. 13 (1): 4613. doi:10.1038/s41467-022-32247-7. PMC 9360402. PMID 35941114.

Further reading

Retrieved from "https://en.wikipedia.org/w/index.php?title=Drosophila_connectome&oldid=1166984672"