Journal article
Beyond spikes: Multiscale computational analysis of in vivo long-term recordings in the cockroach circadian clock



Publication Details
Authors:
Garcia, M.; Rojas, P.
Publisher:
MIT PRESS
Publication year:
2019
Journal:
NETWORK NEUROSCIENCE
Pages range:
944-968
Volume number:
3
Issue number:
4
Start page:
944
End page:
968
Number of pages:
25
ISSN:
2472-1751

Abstract
The circadian clock of the nocturnal Madeira cockroach is located in the accessory medulla, a small nonretinotopic neuropil in the brain's visual system. The clock comprises about 240 neurons that control rhythms in physiology and behavior such as sleep-wake cycles. The clock neurons contain an abundant number of partly colocalized neuropeptides, among them pigment-dispersing factor (PDF), the insects' most important circadian coupling signal that controls sleep-wake rhythms. We performed long-term loose-patch clamp recordings under 12:12-hr light-dark cycles in the cockroach clock in vivo. A wide range of timescales, from milliseconds to seconds, were found in spike and field potential patterns. We developed a framework of wavelet transform-based methods to detect these multiscale electrical events. We analyzed frequencies and patterns of events with interesting dynamic features, such as mixed-mode oscillations reminiscent of sharp-wave ripples. Oscillations in the beta/gamma frequency range (20-40 Hz) were observed to rise at dawn, when PDF is released, peaking just before the onset of locomotor activity of the nocturnal cockroach. We expect that in vivo electrophysiological recordings combined with neuropeptide/antagonist applications and behavioral analysis will determine whether specific patterns of electrical activity recorded in the network of the cockroach circadian clock are causally related to neuropeptide-dependent control of behavior. Author SummaryWe seek to understand how the neuronal network of the cockroach circadian clock controls temporal rhythms in physiology and behavior. Circadian clocks in mammals and insects alike employ neuropeptides for information processing that bypass synaptic information transfer. Neuropeptides appear to work as coupling factors synchronizing and binding neuronal circuits on multiple timescales, employing schemes of temporal encoding. Expanding known techniques with novel approaches, we describe oscillations of electrical events on multiple timescales in long-term in vivo electrophysiological recordings. In future studies, we will combine experimental approaches with the construction of minimal oscillator networks to examine how the cockroach brain controls sleep-wake cycles based on neuropeptide signaling.


Keywords
Circadian and ultradian rhythms, event detection, neuropeptides, Wavelet


Authors/Editors

Last updated on 2019-01-11 at 17:03