Zebrafish and medaka offer insights into the neurobehavioral correlates of vertebrate magnetoreception

Abstract

An impediment to a mechanistic understanding of how some species sense the geomagnetic field (“magnetoreception”) is the lack of vertebrate genetic models that exhibit well-characterized magnetoreceptive behavior and are amenable to whole-brain analysis. We investigated the genetic model organisms zebrafish and medaka, whose young stages are transparent and optically accessible. In an unfamiliar environment, adult fish orient according to the directional change of a magnetic field even in darkness. To enable experiments also in juveniles, we applied slowly oscillating magnetic fields, aimed at generating conflicting sensory inputs during exploratory behavior. Medaka (but not zebrafish) increase their locomotor activity in this assay. Complementary brain activity mapping reveals neuronal activation in the lateral hindbrain during magnetic stimulation. These comparative data support magnetoreception in teleosts, provide evidence for a light-independent mechanism, and demonstrate the usefulness of zebrafish and medaka as genetic vertebrate models for studying the biophysical and neuronal mechanisms underlying magnetoreception.

Nuclear magnetic resonance affects the circadian clock and hypoxia-inducible factor isoforms in zebrafish

“…Cry1 protein was repeatedly reported to be responsible for the light-dependent magnetosensitivity of animals which are able to perceive the MF of the earth, among them also the zebrafish (Takebe et al 2012;Osipova et al 2016). Only recently, a light-independent magnetoreception was found in zebrafish and medaka (Myklatun et al 2018). The NMR therapy-induced effects on the circadian clock in the present study were generated without prior blue or UV light exposition and might consequently be limited to fish, although the study on the entrainment capacity of electromagnetic fields on the circadian clock of human fibroblast cells (Manzella et al 2015) strongly argues against this presumption.…”

Near absence of differential gene expression in the retina of rainbow trout after exposure to a magnetic pulse: implications for magnetoreception

“…A dual-mechanism magnetoreception system, in which retinal cryptochromes function in a magnetic compass and magnetite-based receptors function in a magnetic map, has been proposed in birds [1] and cannot be ruled out in fish. Nevertheless, dissimilarities between the light-dependent compasses of birds and the light-independent compasses of teleosts suggest the possibility that the two are based on different underlying mechanisms [1,15]. The single gene affected by the pulse was g-crystallin M3like (crygm3).…”

Electronic skins with a global attraction

“…Only few animals can derive positional information just from the Earth's magnetic field. For example, organisms such as zebrafish and medaka 7 possess an internal compass that allows them to orient themselves and maintain a consistent direction of travel.…”