Morphology of visual projection neurons supplying premotor area in the brain of the silkmoth Bombyx mori

Abstract Insect olfaction is a suitable model to investigate sensory processing in the brain. Olfactory information is first processed in the antennal lobe and is then conveyed to two second-order centres—the mushroom body calyx and the lateral protocerebrum. Projection neurons processing sex pheromones and plant odours supply the delta area of the inferior lateral protocerebrum (∆ILPC) and lateral horn (LH), respectively. Here, we investigated the neurons arising from these regions in the brain of the silkmoth, Bombyx mori, using mass staining and intracellular recording with a sharp glass microelectrode. The output neurons from the ∆ILPC projected to the superior medial protocerebrum, whereas those from the LH projected to the superior lateral protocerebrum. The dendritic innervations of output neurons from the ∆ILPC formed a subdivision in the ∆ILPC. We discuss pathways for odour processing in higher order centres.

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Two brain pathways initiate distinct forward walking programs in Drosophila

10.1101/798439 ◽

2019 ◽

Cited By ~ 3

Author(s):

Salil S. Bidaye ◽

Meghan Laturney ◽

Amy K. Chang ◽

Yuejiang Liu ◽

Till Bockemühl ◽

...

Keyword(s):

High Velocity ◽

Projection Neurons ◽

Descending Neurons ◽

Specific Manner ◽

Visual Projection ◽

Brain Pathways ◽

Walking Programs ◽

Context Specific ◽

The Brain ◽

Insight Into

SummaryAn animal at rest or engaged in stationary behaviors can instantaneously initiate goal-directed walking. How descending brain inputs trigger rapid transitions from a non-walking state to an appropriate walking state is unclear. Here, we identify two specific neuronal classes in the Drosophila brain that drive two distinct forward walking programs in a context-specific manner. The first class, named P9, consists of descending neurons that drive forward walking with ipsilateral turning. P9 receives inputs from central courtship-promoting neurons and visual projection neurons and is necessary for a male to track a female during courtship. The second class comprises novel, higher order neurons, named BPN, that drives straight, forward walking. BPN is required for high velocity walking and is active during long, fast, straight walking bouts. Thus, this study reveals separate brain pathways for object-directed steering and fast straight walking, providing insight into how the brain initiates different walking programs.

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In vitro eclosion hormone synthesis and secretion in the brain-retrocerebral complexes of the silkworm, Bombyx mori

Journal of Insect Physiology ◽

10.1016/0022-1910(90)90099-2 ◽

1990 ◽

Vol 36 (7) ◽

pp. 489-493 ◽

Cited By ~ 3

Author(s):

Mika Sakakibara ◽

Hajime Fugo

Keyword(s):

Bombyx Mori ◽

Hormone Synthesis ◽

Eclosion Hormone ◽

The Brain ◽

Silkworm Bombyx Mori

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Differential Involvement of Projection Neurons During Emergence of Spontaneous Activity in the Developing Avian Hindbrain

Journal of Neurophysiology ◽

10.1152/jn.90835.2008 ◽

2009 ◽

Vol 101 (2) ◽

pp. 591-602 ◽

Cited By ~ 4

Author(s):

Hiraku Mochida ◽

Gilles Fortin ◽

Jean Champagnat ◽

Joel C. Glover

Keyword(s):

Spontaneous Activity ◽

Projection Neuron ◽

Projection Neurons ◽

Charge Coupled Device ◽

Neuron Populations ◽

Motor Nerves ◽

Differential Involvement ◽

A Charge ◽

The Brain ◽

Calcium Green

To better characterize the emergence of spontaneous neuronal activity in the developing hindbrain, spontaneous activity was recorded optically from defined projection neuron populations in isolated preparations of the brain stem of the chicken embryo. Ipsilaterally projecting reticulospinal (RS) neurons and several groups of vestibuloocular (VO) neurons were labeled retrogradely with Calcium Green-1 dextran amine and spontaneous calcium transients were recorded using a charge-coupled-device camera mounted on a fluorescence microscope. Simultaneous extracellular recordings were made from one of the trigeminal motor nerves (nV) to register the occurrence of spontaneous synchronous bursts of activity. Two types of spontaneous activity were observed: synchronous events (SEs), which occurred in register with spontaneous bursts in nV once every few minutes and were tetrodotoxin (TTX) dependent, and asynchronous events (AEs), which occurred in the intervals between SEs and were TTX resistant. AEs occurred developmentally before SEs and were in general smaller and more variable in amplitude than SEs. SEs appeared at the same stage as nV bursts early on embryonic day 4, first in RS neurons and then in VO neurons. All RS neurons participated equally in SEs from the outset, whereas different subpopulations of VO neurons participated differentially, both in terms of the proportion of neurons that exhibited SEs, the fidelity with which the SEs in individual neurons followed the nV bursts, and the developmental stage at which SEs appeared and matured. The results show that spontaneous activity is expressed heterogeneously among hindbrain projection neuron populations, suggesting its differential involvement in the formation of different functional neuronal circuits.

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