title: Dendrites are dispensable for basic motoneuron function but essential for fine tuning of behavior.
abstract: Dendrites are highly complex 3D structures that define neuronal morphology and connectivity and are the predominant sites for synaptic input. Defects in dendritic structure are highly consistent correlates of brain diseases. However, the precise consequences of dendritic structure defects for neuronal function and behavioral performance remain unknown. Here we probe dendritic function by using genetic tools to selectively abolish dendrites in identified Drosophila wing motoneurons without affecting other neuronal properties. We find that these motoneuron dendrites are unexpectedly dispensable for synaptic targeting, qualitatively normal neuronal activity patterns during behavior, and basic behavioral performance. However, significant performance deficits in sophisticated motor behaviors, such as flight altitude control and switching between discrete courtship song elements, scale with the degree of dendritic defect. To our knowledge, our observations provide the first direct evidence that complex dendrite architecture is critically required for fine-tuning and adaptability within robust, evolutionarily constrained behavioral programs that are vital for mating success and survival. We speculate that the observed scaling of performance deficits with the degree of structural defect is consistent with gradual increases in intellectual disability during continuously advancing structural deficiencies in progressive neurological disorders.
authors.affiliation: Institute of Neurobiology, Johannes Gutenberg University of Mainz, 55099 Mainz, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Ryglewski
authors.affiliation: Institute of Neurobiology, Johannes Gutenberg University of Mainz, 55099 Mainz, Germany.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Kadas
authors.affiliation: Institute of Neurobiology, Johannes Gutenberg University of Mainz, 55099 Mainz, Germany.
authors.forename: Katie
authors.initials: K
authors.lastname: Hutchinson
authors.affiliation: Institute of Neurobiology, Johannes Gutenberg University of Mainz, 55099 Mainz, Germany.
authors.forename: Natalie
authors.initials: N
authors.lastname: Schuetzler
authors.affiliation: Institute of Neurobiology, Johannes Gutenberg University of Mainz, 55099 Mainz, Germany.
authors.forename: Fernando
authors.initials: F
authors.lastname: Vonhoff
authors.affiliation: Institute of Neurobiology, Johannes Gutenberg University of Mainz, 55099 Mainz, Germany cduch@uni-mainz.de.
authors.forename: Carsten
authors.initials: C
authors.lastname: Duch
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D003712:Dendrites / Q000502:physiology*; D004331:Drosophila melanogaster / Q000502:physiology*; D005426:Flight, Animal / Q000502:physiology; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D009046:Motor Neurons / Q000166:cytology* / Q000502:physiology*; D018408:Patch-Clamp Techniques; D018709:Statistics, Nonparametric; D014921:Wings, Animal / Q000294:innervation
keywords: Drosophila; courtship; dendrite; motor behavior; synapse