Temperature effects on neuronal firing rates and tonic-to-bursting transitions

Burek, Manuela; Follmann, Rosangela; Rosa, Epaminondas

doi:10.1016/j.biosystems.2019.03.003

Cited by 18 publications

(6 citation statements)

References 29 publications

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“…Notice that a Q 15 temperature coefficient of 2.4 (from 22° to 37 °C) is in good agreement with the Q 10 = 2.7 observed for the repetitive firing frequency of squid axon [ 33 ] and the Q 10 = 2.3–2.8 for the rate constants of Nav channel activation of squid axon [ 45 ] and node of Ranvier [ 14 ]. As clarified by [ 37 ] and others [ 4 , 22 , 41 ], an increased rate of activation of Na + and K + channels shorten the AP duration and speed up the ion channel recovery that support the next AP within shorter times allowing the cell to generate higher firing rates.…”

Section: Discussionmentioning

confidence: 99%

“…The second regards the reason why the intermittent firing is more frequently observed at higher temperature. A possibility is that temperature changes favor the switch from continuous to intermittent firing, as observed in several neurons with increasing [ 4 , 11 , 18 , 19 , 21 , 39 , 40 , 68 ] or lowering the temperature [ 34 , 35 ]. The switch is likely induced by the increased rate constants of Na + and K + channels activation that generate repetitive firing in neurons and whose frequency accelerates with temperature [ 21 , 40 ].…”

Section: Discussionmentioning

confidence: 99%

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Two firing modes and well-resolved Na+, K+, and Ca2+ currents at the cell-microelectrode junction of spontaneously active rat chromaffin cell on MEAs

Marcantoni

Chiantia

Tomagra

et al. 2022

Pflugers Arch - Eur J Physiol

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We recorded spontaneous extracellular action potentials (eAPs) from rat chromaffin cells (CCs) at 37 °C using microelectrode arrays (MEAs) and compared them with intracellularly recorded APs (iAPs) through conventional patch clamp recordings at 22 °C. We show the existence of two distinct firing modes on MEAs: a ~ 4 Hz irregular continuous firing and a frequent intermittent firing mode where periods of high-intraburst frequency (~ 8 Hz) of ~ 7 s duration are interrupted by silent periods of ~ 12 s. eAPs occurred either as negative- or positive-going signals depending on the contact between cell and microelectrode: either predominantly controlled by junction-membrane ion channels (negative-going) or capacitive/ohmic coupling (positive-going). Negative-going eAPs were found to represent the trajectory of the Na+, Ca2+, and K+ currents passing through the cell area in tight contact with the microelectrode during an AP (point-contact junction). The inward Nav component of eAPs was blocked by TTX in a dose-dependent manner (IC50 ~ 10 nM) while the outward component was strongly attenuated by the BK channel blocker paxilline (200 nM) or TEA (5 mM). The SK channel blocker apamin (200 nM) had no effect on eAPs. Inward Nav and Cav currents were well-resolved after block of Kv and BK channels or in cells showing no evident outward K+ currents. Unexpectedly, on the same type of cells, we could also resolve inward L-type currents after adding nifedipine (3 μM). In conclusion, MEAs provide a direct way to record different firing modes of rat CCs and to estimate the Na+, Ca2+, and K+ currents that sustain cell firing and spontaneous catecholamines secretion.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Two firing modes and well-resolved Na+, K+, and Ca2+ currents at the cell-microelectrode junction of spontaneously active rat chromaffin cell on MEAs

Marcantoni

Chiantia

Tomagra

et al. 2022

Pflugers Arch - Eur J Physiol

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“…The electrical properties of the coil could change due to the increased temperature of the windings, which might partly explain the drop of coil current at higher rTMS frequency. A temperature control or cooling system might be required when the current is further increased, since heating of the coil would potentially lead to a local brain temperature change that might influence neural excitability [78][79][80]. Moreover, the coil generated light vibrations and sounds during stimulation.…”

Section: Discussionmentioning

confidence: 99%

A C-shaped miniaturized coil for transcranial magnetic stimulation in rodents

et al. 2023

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Objective. Transcranial magnetic stimulation (TMS) is a non-invasive technique widely used for neuromodulation. Animal models are essential for investigating the underlying mechanisms of TMS. However, the lack of miniaturized coils hinders the TMS studies in small animals, since most commercial coils are designed for humans and thus incapable of focal stimulation in small animals. Furthermore, it is difficult to perform electrophysiological recordings at the TMS focal point using conventional coils. Approach. We designed, fabricated, and tested a novel miniaturized TMS coil (4-by-7 mm) that consisted of a C-shaped iron powder core and insulated copper wires (30 turns). The resulting magnetic and electric fields were characterized with experimental measurements and finite element modeling. The efficacy of this coil in neuromodulation was validated with electrophysiological recordings of single-unit activities (SUAs), somatosensory evoked potentials (SSEPs), and motor evoked potentials (MEPs) in rats (n=32) following repetitive TMS (rTMS; 3 min, 10 Hz). Main results. This coil could generate a maximum magnetic field of 460 mT and an electric field of 7.2 V/m in the rat brain according to our simulations. With subthreshold rTMS focally delivered over the sensorimotor cortex, mean firing rates of primary somatosensory and motor cortical neurons significantly increased (154±5% and 160±9% from the baseline level, respectively); MEP and SSEP amplitude significantly increased (136±9%) and decreased (74±4%), respectively. Significance. This miniaturized C-shaped coil enabled focal TMS and simultaneous electrophysiological recording/stimulation at the TMS focal point. It provided a useful tool to investigate the neural responses and underlying mechanisms of TMS in small animal models. Using this paradigm, we for the first time observed distinct modulatory effects on SUAs, SSEPs, and MEPs with the same rTMS protocol in anesthetized rats. These results suggested that multiple neurobiological mechanisms in the sensorimotor pathways were differentially modulated by rTMS.

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“…Temperature is recognized as one of the most significant environmental factors affecting animal physiology 21 . Despite being understudied, thermal influences on neuronal activity play a vital role, leading to alterations in the frequency of neuron action potentials [21][22][23][24] . Temperature variations impact the activation and inactivation of various ion channels, such as the voltagedependent K + , Na + , and Ca 2+ channels, ultimately influencing the generation of action potentials 25,26 .…”

Section: Introductionmentioning

confidence: 99%

Thermal effects and ephaptic entrainment in Hodgkin-Huxley model

Sousa,

Cunha,

Corso

et al. 2024

Preprint

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The brain is understood as an intricate biological system composed of multiple elements. It is susceptible to diverse physical and chemical influences, including temperature. The literature widely explores the conditions that affect synapses in the context of cellular communications. However, the understanding of how brain global physical conditions can modulate ephaptic communication remains limited, because the still poorly understood nature of ephapticity. This study proposes an adaptation of the Hodgkin and Huxley model, HH-E, to investigate the effects of ephaptic entrainment in response to thermal changes. The analysis focus on two distinct neuronal regimes: subthreshold and suprathreshold. In the subthreshold regime, the circular statistic is used to show the phase differences dependence on temperature. In the suprathreshold regime, the Population Vector and the Inter-Spike Interval are used to estimate phase preferences and changes in the spiking pattern. Temperature affects positively the HH-E model spiking frequency. At high temperatures the HH-E model collapses and no more spiking are observed. Moreover, temperature difference improves the anti-phase between spikes and the ephaptic external signal. In the suprathreshold regime, the ephaptic entrainment is influenced by temperature, specially at low frequencies. Finally, this study reveals the susceptibility of ephaptic entrainment to temperature variations in both subthreshold and suprathreshold regimes and discusses the importance of ephaptic communication in pathological contexts in which temperature play an important role in neural physiology, such as inflammatory processes, fever and epileptic seizures.

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Temperature effects on neuronal firing rates and tonic-to-bursting transitions

Cited by 18 publications

References 29 publications

Two firing modes and well-resolved Na+, K+, and Ca2+ currents at the cell-microelectrode junction of spontaneously active rat chromaffin cell on MEAs

Two firing modes and well-resolved Na+, K+, and Ca2+ currents at the cell-microelectrode junction of spontaneously active rat chromaffin cell on MEAs

A C-shaped miniaturized coil for transcranial magnetic stimulation in rodents

Thermal effects and ephaptic entrainment in Hodgkin-Huxley model

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