Non-invasive visual evoked potentials under sevoflurane versus ketamine-xylazine in rats

Castoldi, Valerio; d’Isa, Raffaele; Marenna, Silvia; Comı, Gıancarlo; Leocani, Letizia

doi:10.1016/j.heliyon.2021.e08360

Cited by 3 publications

(8 citation statements)

References 51 publications

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“…Results of the present study add to this literature by demonstrating that obligatory components of the mouse auditory ERP are also significantly diminished by NMDA receptor disruption. The effects of urethane anesthesia observed on mouse ERPs here are also consistent with general observations of the influence of anesthetics on evoked responses in humans and other animals [7], [8], [13], [19], [55]. Simulated ERPs were generated using state encodings spanning beyond the range of values used during training, allowing a characterization of the dynamics in ERP morphology throughout this continuum of consciousness.…”

Section: Discussionsupporting

confidence: 81%

“…This is precisely the opposite of what would be expected if the differences between groups were principally due to age-related hearing loss [42]. Aside from this, other studies have also considered using different cohorts of animals in treatment groups to be a valid approach [13], [19]. As such, while it would have been preferable to use the same animals in all four conditions, this caveat does not demand a substantial reinterpretation of the results.…”

Section: Discussionmentioning

confidence: 98%

“…It is evident from the synthetic ERP waveforms generated by the model (Figure 3b-c) that these are in close agreement (r 2 > 0.9) with grand-average ERPs from mice in each condition. It is feasible that other anaesthetics could produce different ERP morphology changes [13], [19], [55]. Furthermore, more subtle differences in state of conscious awareness (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…In a comparison between ketamine-xylazine and urethane-xylazine anesthesia in two groups of mice, Lee and Jones [13] concluded that urethane preserved greater physiological functioning. In another comparative study, Castoldi et al [19] found that sevoflurane anesthesia attenuated visual evoked potentials more than ketamine-xylazine anesthesia in two groups of rats. These findings suggest that anesthetic agents can be placed on a spectrum in terms of their effects on sensory neurophysiology.…”

Section: Introductionmentioning

confidence: 97%

“…Given inherent difficulties in ascertaining the underlying neurophysiology reflected by these noninvasive measurements in humans, this research benefits from using experimental animals [13][14][15][16][17][18][19][20][21][22][23]. Preclinical studies accommodate more frequent use of invasive recording technologies and greater degrees of manipulation than are typically possible with human subjects, which ought to help decipher precisely how specific component(s) are influenced by genetic, pharmacological, environmental, and behavioural conditions.…”

Section: Introductionmentioning

confidence: 99%

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Modelling mouse auditory response dynamics along a continuum of consciousness using a deep recurrent neural network

O’Reilly

2022

J. Neural Eng.

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Objective. Understanding neurophysiological changes that accompany transitions between anaesthetized and conscious states is a key objective of anesthesiology and consciousness science. This study aimed to characterize the dynamics of auditory-evoked potential morphology in mice along a continuum of consciousness. Approach. Epidural field potentials were recorded from above the primary auditory cortices of two groups of laboratory mice: urethane-anaesthetized (A, n = 14) and conscious (C, n = 17). Both groups received auditory stimulation in the form of a repeated pure-tone stimulus, before and after receiving 10 mg kg−1 i.p. ketamine (AK and CK). Evoked responses were then ordered by ascending sample entropy into AK, A, CK, and C, considered to reflect physiological correlates of awareness. These data were used to train a recurrent neural network (RNN) with an input parameter encoding state. Model outputs were compared with grand-average event-related potential (ERP) waveforms. Subsequently, the state parameter was varied to simulate changes in the ERP that occur during transitions between states, and relationships with dominant peak amplitudes were quantified. Main results. The RNN synthesized output waveforms that were in close agreement with grand-average ERPs for each group (r 2 > 0.9, p < 0.0001). Varying the input state parameter generated model outputs reflecting changes in ERP morphology predicted to occur between states. Positive peak amplitudes within 25–50 ms, and negative peak amplitudes within 50–75 ms post-stimulus-onset, were found to display a sigmoidal characteristic during the transition from anaesthetized to conscious states. In contrast, negative peak amplitudes within 0–25 ms displayed greater linearity. Significance. This study demonstrates a method for modelling changes in ERP morphology that accompany transitions between states of consciousness using an RNN. In future studies, this approach may be applied to human data to support the clinical use of ERPs to predict transition to consciousness.

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Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Modelling mouse auditory response dynamics along a continuum of consciousness using a deep recurrent neural network

O’Reilly

2022

J. Neural Eng.

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Modelling mouse auditory response dynamics along a continuum of consciousness using a deep recurrent neural network

O’Reilly

2022

Preprint

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ObjectiveUnderstanding neurophysiological changes that accompany transitions between anaesthetized and conscious states is a key objective of anesthesiology and consciousness science. This study aimed to characterize the dynamics of auditory-evoked potential morphology in mice along a continuum of consciousness.ApproachEpidural field potentials were recorded from above the primary auditory cortices of two groups of laboratory mice: urethane-anaesthetized (A, n = 14) and conscious (C, n = 17). Both groups received auditory stimulation in the form of a repeated pure-tone stimulus, before and after receiving 10 mg/kg i.p. ketamine (AK and CK). Evoked responses were then ordered by ascending sample entropy into AK, A, CK, and C, considered to reflect physiological correlates of awareness. These data were used to train a recurrent neural network (RNN) with an input parameter encoding state. Model outputs were compared with grand-average event-related potential (ERP) waveforms. Subsequently, the state parameter was varied to simulate changes in the ERP that occur during transitions between states, and relationships with dominant peak amplitudes were quantified.Main resultsThe RNN synthesized output waveforms that were in close agreement with grand-average ERPs for each group (r2 > 0.9, p < 0.0001). Varying the input state parameter generated model outputs reflecting changes in ERP morphology predicted to occur between states. Positive peak amplitudes within 25 to 50 ms, and negative peak amplitudes within 50 to 75 ms post-stimulus-onset, were found to display a sigmoidal characteristic during the transition from anaesthetized to conscious states. In contrast, negative peak amplitudes within 0 to 25 ms displayed greater linearity.SignificanceThis study demonstrates a method for modelling changes in ERP morphology that accompany transitions between states of consciousness using a RNN. In future studies, this approach may be applied to human data to support the clinical use of ERPs to predict transition to consciousness.

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Application of remimazolam-0.6% sevoflurane anesthesia for flash visual evoked potential monitoring during pituitary adenoma resection: a non-inferiority randomized controlled trial

Shi,

Tang,

et al. 2024

BMC Anesthesiol

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Background Flash visual evoked potential (FVEP) is a critical method for monitoring intraoperative visual function during neurosurgery. A new benzodiazepine drug called remimazolam has recently been used for general anesthesia. However, the impact of remimazolam on FVEP remains unclear. Therefore, we aimed to investigate how remimazolam, in comparison to propofol, when combined with 0.6% sevoflurane anesthesia, affects the FVEP waveform during pituitary adenoma resection. Methods Overall, 36 patients undergoing pituitary adenoma resection under general anesthesia were randomly assigned to either the remimazolam group (Group R) or the propofol group (Group P) in a prospective, randomized, controlled, non-inferiority trial. For anesthesia induction, a bolus of 0.2 mg/kg remimazolam or 2 mg/kg propofol was intravenously infused for approximately one minute. The anesthesia was maintained by continuous infusion of either remimazolam (0.7-1.0 mg/kg/h) or propofol (4–6 mg/kg/h), in combination with 0.6% sevoflurane, aimed at sustaining the bispectral index (BIS) within the range of 40–60. The primary outcome was the N75-P100 amplitude of FVEP recorded at approximately 20 min after intubation (T0). 10% of the amplitude at T0 in group P was defined as the non-inferiority margin (δ). Confidence interval testing was used to evaluate the non-inferiority hypothesis. The secondary outcomes covered the P100 latency of FVEP, electroretinogram (ERG) b wave amplitude, demographic characteristics, hemodynamics, and occurrence of adverse events. Results The BIS index during anesthesia was comparable between the groups at the same measured time points (P > 0.05). The N75-P100 amplitude at T0 in group R was 7.64 ± 1.36 µV, while it was 6.96 ± 0.95 µV in group P (P = 0.09), with a mean difference of 0.68 µV (95% CI, -0.11 µV to 1.48 µV). The δ was set at 0.7 and the lower limit of the 95% CI exceeded the -δ. Both remimazolam and propofol had little effect on ERG b-wave amplitudes. At the designated time points, FVEP amplitude and P100 latency displayed no appreciable variation between the two groups (P > 0.05). Furthermore, there were no significant differences in the incidence of adverse events related to anesthesia, needle electrodes, or surgery between the two groups (P > 0.05). Conclusion Our findings suggest that remimazolam-0.6% sevoflurane is non-inferior to propofol-0.6% sevoflurane for general anesthesia, based on the FVEP N75-P100 amplitude. The electrophysiological data obtained in both groups indicate that reproducible and stable FVEP and ERG waveforms can be acquired at set time points. Therefore, for reliable FVEP monitoring, remimazolam-0.6% sevoflurane appears to be a safe and effective protocol in general anesthesia. Trials registration This study was registered on chictr.org.cn (ChiCTR2200056803, 17/02/2022).

show abstract

Non-invasive visual evoked potentials under sevoflurane versus ketamine-xylazine in rats

Cited by 3 publications

References 51 publications

Modelling mouse auditory response dynamics along a continuum of consciousness using a deep recurrent neural network

Modelling mouse auditory response dynamics along a continuum of consciousness using a deep recurrent neural network

Modelling mouse auditory response dynamics along a continuum of consciousness using a deep recurrent neural network

Application of remimazolam-0.6% sevoflurane anesthesia for flash visual evoked potential monitoring during pituitary adenoma resection: a non-inferiority randomized controlled trial

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