Electrophysiology and the magnetic sense: a guide to best practice

Abstract

Magnetoreception, sensing the Earth’s magnetic field, is used by many species in orientation and navigation. While this is established on the behavioural level, there is a severe lack in knowledge on the underlying neuronal mechanisms of this sense. A powerful technique to study the neuronal processing of magnetic cues is electrophysiology but, thus far, few studies have adopted this technique. Why is this the case? A fundamental problem is the introduction of electromagnetic noise (induction) caused by the magnetic stimuli, within electrophysiological recordings which, if too large, prevents feasible separation of neuronal signals from the induction artefacts. Here, we address the concerns surrounding the use of electromagnetic coils within electrophysiology experiments and assess whether these would prevent viable electrophysiological recordings within a generated magnetic field. We present calculations of the induced voltages in typical experimental situations and compare them against the neuronal signals measured with different electrophysiological techniques. Finally, we provide guidelines that should help limit and account for possible induction artefacts. In conclusion, if great care is taken, viable electrophysiological recordings from magnetoreceptive cells are achievable and promise to provide new insights on the neuronal basis of the magnetic sense.

Integration and evaluation of magnetic stimulation in physiology setups

“…Hence, if instantaneous magnetic stimulus changes are applied in a recording, they will occur transiently with very short latencies in comparison to biological responses and can be excluded from the analyses. On the other hand, if slow magnetic stimuli are applied, the induced artifacts can be expected to be smaller in amplitude because less change of the magnetic field per time will result in smaller artifact induction [42]. Magnetic stimulus transitions might be chosen to be slow enough to fall below the physiological recording's frequency band.…”

“…If possible, the induction artifact should be further minimized e.g. by the arrangement of the cables or the use of twisted-pair cables [42]. If spike sorting with multiple electrodes is possible, the induction artifact is easy to separate from biological signals.…”

Unraveling the Neural Circuits: Techniques, Opportunities and Challenges in Epilepsy Research

“…Afterwards, Erlanger et al began to record bioelectricity using oscilloscopes, marking the beginning of modern electrophysiology (Breathnach and Moynihan 2014 ). After several generations of evolution, electrophysiology has evolved from the early stage of synchronous electrical activities of a large number of cells, to non-invasive microelectrodes at the cellular level (Fenton et al 2022 ; Tomasello and Wlodkowic 2022 ). Calcium ions can be used as markers of neuronal excitability, and their dynamic imaging capabilities within cells have long been a focus of attention (Bonnin et al 2024 ).…”