Citation

Dewell RB, Gabbiani F. J. Neurophysiol. 2018; 120(4): 1753-1764.

Affiliation

Neuroscience, Baylor College of Medicine, United States.

Copyright

(Copyright © 2018, American Physiological Society)

DOI

10.1152/jn.00363.2018

PMID

30044671

Abstract

All animals must detect impending collisions to escape and reliably discriminate them from non-threatening stimuli thus preventing false alarms. Therefore, it is no surprise that animals have evolved highly selective and sensitive neurons dedicated to such tasks. We examined a well-studied collision detection neuron in the grasshopper Schistocerca americana using in vivo electrophysiology, pharmacology, and computational modeling. This lobula giant movement detector (LGMD) neuron is excitable by inputs originating from each ommatidia of the compound eye. It possesses many intrinsic properties that increase its selectivity to objects approaching on a collision course, including switching between burst and non-burst firing. Here, we demonstrate that the LGMD neuron exhibits a large M current, generated by non-inactivating K⁺ channels, that shortens the temporal window of dendritic integration, regulates a firing mode switch between burst and isolated spiking, increases the precision of spike timing, and increases the reliability of spike propagation to downstream motor centers. By revealing how the M current increases the LGMD's ability to detect impending collisions our results suggest that similar channels may play an analogous role in other collision detection circuits.

Language: en

Keywords

M current; burst firing; collision avoidance; lobula giant movement detector; spike timing