Dynamic changes in rhythmic and arrhythmic neural signatures in the subthalamic nucleus induced by anaesthesia and tracheal intubation

Abstract

Background: Subcortical structures, including the basal ganglia, have been proposed to be crucial for arousal, consciousness, and behavioural responsiveness. How the basal ganglia contribute to the loss and recovery of consciousness during anaesthesia has, however, not yet been well characterised. Methods: Twelve patients with advanced Parkinson's disease, who were undergoing deep brain stimulation (DBS) electrode implantation in the subthalamic nucleus (STN), were included in this study. Local field potentials (LFPs) were recorded from the DBS electrodes and EEG was recorded from the scalp during induction of general anaesthesia (with propofol and sufentanil) and during tracheal intubation. Neural signatures of loss of consciousness and of the expected arousal during intubation were sought in the STN and EEG recordings. Results: Propofolesufentanil anaesthesia resulted in power increases in delta, theta, and alpha frequencies, and broadband power decreases in higher frequencies in both STN and frontal cortical areas. This was accompanied by increased STNefrontal cortical coherence only in the alpha frequency band (119 [68]%; P¼0.0049). We observed temporal activity changes in STN after tracheal intubation, including power increases in high-beta (22e40 Hz) frequency (98 [123]%; P¼0.0064) and changes in the power-law exponent in the power spectra at lower frequencies (2e80 Hz), which were not observed in the frontal cortex. During anaesthesia, the dynamic changes in the high-gamma power in STN LFPs correlated with the power-law exponent in the power spectra at lower frequencies (2e80 Hz). Conclusions: Apart from similar activity changes in both STN and cortex associated with anaesthesia-induced unresponsiveness, we observed specific neuronal activity changes in the STN in response to the anaesthesia and tracheal intubation. We also show that the power-law exponent in the power spectra in the STN was modulated by tracheal intubation in anaesthesia. Our results support the hypothesis that subcortical nuclei may play an important role in the loss and return of responsiveness.

Clinical applications of EEG power spectra aperiodic component analysis: A mini-review

“…Several and relevant points related to 1/f should be discussed and properly considered when interpreting any pathological changes. In particular, we would like to emphasize that 1/f may flatten as an effect of aging (Dave et al, 2018; or may steepen in pharmacological induced unconsciousness (Colombo et al, 2019;Gao et al, 2017;Huang et al, 2020) or may discriminate between different states of consciousness (present/reduced or abolished) (Colombo et al, 2019). Moreover, 1/f slope has been shown to be a marker of states of reduced arousal, including sleep stages as well as anesthesia (Lendner et al, 2020;Miskovic et al, 2019;Muthukumaraswamy and Liley, 2018;Pereda et al, 1998;Shen et al, 2003).…”

The aperiodic exponent of subthalamic field potentials reflects excitation/inhibition balance in Parkinsonism: a cross-species study in vivo

“…The latter is supported by multiple studies showing that aperiodic exponents in non-invasive EEG and invasive LFP measurements were modulated by sleep and anaesthesia, with lower exponents, corresponding to slower decay of power with increasing frequencies, during the conscious state, which is linked with increased excitation. Inversely, higher aperiodic exponents, corresponding to faster decay of power with increasing frequencies, were observed during the unconscious state (NREM sleep, anaesthesia), which is linked with more inhibition (Colombo et al, 2019; Huang et al, 2020; Lendner et al, 2020; Miskovic et al, 2019; Niethard et al, 2016; Waschke et al, 2021). In addition, Gao and colleagues found that theta cycle-modulated E/I changes in the rat hippocampus are reflected in the per-cycle PSD exponent of hippocampal LFPs calculated at different theta phases (peaks or troughs) confirming the E/I hypothesis for LFPs (Gao et al, 2017).…”

Nucleus accumbens neurons expressing dopamine D1 receptors modulate states of consciousness in sevoflurane anesthesia

“…[10][11][12][13] However, whether the NAc participates in regulating states of consciousness in GA remains largely unknown. Notably, a few recent laboratory and clinical studies have begun to highlight the importance of the basal ganglia and limbic system in the mechanisms of action of GA; 3,14,15 interestingly, the NAc acts as an important interface between these two systems. 16,17 Recent neuroimaging evidence has also suggested that the NAc may be essential for modulating anesthetic-induced unconsciousness.…”