Awake State Research Articles

Tracking the effects of propofol, sevoflurane and (S)-ketamine anesthesia using an unscented Kalman filter-based neural mass model

Objective. Neural mass model (NMM) has been widely used to investigate the neurophysiological mechanisms of anesthetic drugs induced general anesthesia (GA). However, whether the parameters of NMM could track the effects of anesthesia still unknown. Approach. We proposed using the cortical NMM (CNMM) to infer the potential neurophysiological mechanism of three different anesthetic drugs (i.e. propofol, sevoflurane, and (S)-ketamine) induced GA, and we employed unscented Kalman filter (UKF) to track any change in raw electroencephalography (rEEG) in frontal area during GA. We did this by estimating the parameters of population gain [i.e. excitatory/inhibitory postsynaptic potential (EPSP/IPSP, i.e. parameter A/B in CNMM) and the time constant rate of EPSP/IPSP (i.e. parameter a/b in CNMM). We compared the rEEG and simulated EEG (sEEG) from the perspective of spectrum, phase-amplitude coupling (PAC), and permutation entropy (PE). Main results. Under three estimated parameters (i.e. A, B, and a for propofol/sevoflurane or b for (S)-ketamine), the rEEG and sEEG had similar waveforms, time-frequency spectra, and PAC patterns during GA for the three drugs. The PE curves derived from rEEG and sEEG had high correlation coefficients (propofol: 0.97 ± 0.03, sevoflurane: 0.96 ± 0.03, (S)-ketamine: 0.98 ± 0.02) and coefficients of determination (R 2) (propofol: 0.86 ± 0.03, sevoflurane: 0.68 ± 0.30, (S)-ketamine: 0.70 ± 0.18). Except for parameter A for sevoflurane, the estimated parameters for each drug in CNMM can differentiate wakefulness and non-wakefulness states. Compared with the simulation of three estimated parameters, the UKF-based CNMM had lower tracking accuracy under the simulation of four estimated parameters (i.e. A, B, a, and b) for three drugs. Significance. The results demonstrate that a combination of CNMM and UKF could track the neural activities during GA. The EPSP/IPSP and their time constant rate can interpret the anesthetic drug’s effect on the brain, and can be used as a new index for depth of anesthesia monitoring.

Sleep fMRI with simultaneous electrophysiology at 9.4 T in male mice

Sleep is ubiquitous and essential, but its mechanisms remain unclear. Studies in animals and humans have provided insights of sleep at vastly different spatiotemporal scales. However, challenges remain to integrate local and global information of sleep. Therefore, we developed sleep fMRI based on simultaneous electrophysiology at 9.4 T in male mice. Optimized un-anesthetized mouse fMRI setup allowed manifestation of NREM and REM sleep, and a large sleep fMRI dataset was collected and openly accessible. State dependent global patterns were revealed, and state transitions were found to be global, asymmetrical and sequential, which can be predicted up to 17.8 s using LSTM models. Importantly, sleep fMRI with hippocampal recording revealed potentiated sharp-wave ripple triggered global patterns during NREM than awake state, potentially attributable to co-occurrence of spindle events. To conclude, we established mouse sleep fMRI with simultaneous electrophysiology, and demonstrated its capability by revealing global dynamics of state transitions and neural events.

Dynamic 3D imaging of cerebral blood flow in awake mice using self-supervised-learning-enhanced optical coherence Doppler tomography

Cerebral blood flow (CBF) is widely used to assess brain function. However, most preclinical CBF studies have been performed under anesthesia, which confounds findings. High spatiotemporal-resolution CBF imaging of awake animals is challenging due to motion artifacts and background noise, particularly for Doppler-based flow imaging. Here, we report ultrahigh-resolution optical coherence Doppler tomography (µODT) for 3D imaging of CBF velocity (CBFv) dynamics in awake mice by developing self-supervised deep-learning for effective image denoising and motion-artifact removal. We compare cortical CBFv in awake vs. anesthetized mice and their dynamic responses in arteriolar, venular and capillary networks to acute cocaine (1 mg/kg, i.v.), a highly addictive drug associated with neurovascular toxicity. Compared with awake, isoflurane (2-2.5%) induces vasodilation and increases CBFv within 2-4 min, whereas dexmedetomidine (0.025 mg/kg, i.p.) does not change vessel diameters nor flow. Acute cocaine decreases CBFv to the same extent in dexmedetomidine and awake states, whereas decreases are larger under isoflurane, suggesting that isoflurane-induced vasodilation might have facilitated detection of cocaine-induced vasoconstriction. Awake mice after chronic cocaine show severe vasoconstriction, CBFv decreases and vascular adaptations with extended diving arteriolar/venular vessels that prioritize blood supply to deeper cortical capillaries. The 3D imaging platform we present provides a powerful tool to study dynamic changes in vessel diameters and morphology alongside CBFv networks in the brain of awake animals that can advance our understanding of the effects of drugs and disease conditions (ischemia, tumors, wound healing).

Locus coeruleus noradrenergic neurons phase-lock to prefrontal and hippocampal infra-slow rhythms that synchronize to behavioral events.

The locus coeruleus (LC) is the primary source of noradrenergic projections to the forebrain, and, in prefrontal cortex, is implicated in decision-making and executive function. LC neurons phase-lock to cortical infra-slow wave oscillations during sleep. Such infra-slow rhythms are rarely reported in awake states, despite their interest, since they correspond to the time scale of behavior. Thus, we investigated LC neuronal synchrony with infra-slow rhythms in awake rats performing an attentional set-shifting task. Local field potential (LFP) oscillation cycles in prefrontal cortex and hippocampus on the order of 0.4 Hz phase-locked to task events at crucial maze locations. Indeed, successive cycles of the infra-slow rhythms showed different wavelengths, as if they are periodic oscillations that can reset phase relative to salient events. Simultaneously recorded infra-slow rhythms in prefrontal cortex and hippocampus could show different cycle durations as well, suggesting independent control. Most LC neurons (including optogenetically identified noradrenergic neurons) recorded here were phase-locked to these infra-slow rhythms, as were hippocampal and prefrontal units recorded on the LFP probes. The infra-slow oscillations also phase-modulated gamma amplitude, linking these rhythms at the time scale of behavior to those coordinating neuronal synchrony. This would provide a potential mechanism where noradrenaline, released by LC neurons in concert with the infra-slow rhythm, would facilitate synchronization or reset of these brain networks, underlying behavioral adaptation.

A comparison of resting-state eyes-closed and dark-room alpha-band activity in children.

In a relaxed and awake state with the eyes closed, 8-12 Hz neural oscillations are the dominant rhythm, most prominent in parietal-occipital regions. Resting-state (RS) alpha is associated with processing speed and is also thought to be central to how networks process information. Unfortunately, the RS eyes-closed (EC) exam can only be used with individuals who can remain awake with their eyes closed for an extended period. As such, infants, toddlers, and individuals with intellectual disabilities are usually excluded from RS alpha studies. Previous research suggests obtaining RS alpha measures in a dark room with the eyes open as a viable alternative to the traditional RS EC exam. To further explore this, RS EC and RS dark room (DR) eyes-open alpha activity was recorded using magnetoencephalography in children with typical development (TD; N = 37) and children with autism spectrum disorder (ASD; N = 30) 6.9-12.6 years old. Findings showed good reliability for the RS EC and DR peak alpha frequency (frequency with strongest alpha power; interclass correlation (ICC) = 0.83). ICCs for posterior alpha power were slightly lower (ICCs in the 0.70 s), with an ~ 5% reduction in posterior alpha power in the DR than EC condition. No differences in the EC and DR associations were observed between the TD and ASD groups. Finally, age was associated with both EC and DR peak alpha frequency. Findings thus indicate the DR exam as a viable way to obtain RS alpha measures in populations frequently excluded from electrophysiology RS studies.

Cerebral cortex and hippocampus neural interaction during vagus nerve stimulation under in vivo large-scale imaging

The purpose of this study was to study mechanisms of VNS modulation from a single neuron perspective utilizing a practical observation platform with single neuron resolution and widefield, real-time imaging coupled with an animal model simultaneously exposing the cerebral cortex and the hippocampus. We utilized the observation platform characterized of widefield of view, real-time imaging, and high spatiotemporal resolution to obtain the neuronal activities in the cerebral cortex and the hippocampus during VNS in awake states and under anesthesia. Some neurons in the hippocampus were tightly related to VNS modulation, and varied types of neurons showed distinct responses to VNS modulation. We utilized such an observation platform coupled with a novel animal model to obtain more information on neuron activities in the cerebral cortex and the hippocampus, providing an effective method to further study the mechanisms of therapeutic effects modulated by VNS.

Bio-inspired wake tracking and phase matching of two diagonal flapping swimmers

Wake interaction provides hydrodynamic gain and flow-aided navigation in fish schools. The lateral spacing Ly and phase angle Φ relative to upstream wake are two important states for downstream swimmers. In this paper, the lateral wake tracking and phase matching of two diagonal flapping swimmers are studied through experiments. Bio-inspired differential pressure (DP) sensing on the downstream swimmer is adopted to capture the wake interaction features. Two DP sensing strategies, the symmetrical differential pressure (SDP) and leading edge differential pressure (LDP), are employed to capture the wake interaction features. SDP measures the pressure difference of two symmetrical ports on the two sides of the downstream swimmer, and LDP measures the pressure difference of leading edge port against the two side ports. One-dimensional convolutional neural networks (1D CNN) with a parallel structure are trained to decode wake interaction states (Ly and Φ) based on DP signals. The 1D CNN model is trained and tested offline and is used to estimate the wake interaction states online. Three demonstrations of online lateral wake tracking and phase matching control are carried out. Compared with SDP, LDP predicts Ly and Φ more accurately. It is found that the downstream wakes are more compact after control, which is consistent with high propulsive efficiency mode.

EEG Correlates of suicidal intentions in depressive patients who survived and have not been ill with COVID-19

IntroductionThe COVID-19 pandemic has caused an increase in suicidal intentions and attempts. One of the ways to prevent suicides is the timely detection of suicidal intentions. In this regard, it seems relevant to search for objective markers of suicidal intentions.ObjectivesThe aim of the study is to identify EEG correlates of suicidal intentions in depressive patients who survived and not have been ill with COVID-19.MethodsThe study included 30 female patients aged 16-25 years with depressive disorders (F31.3-4, F21.3-4 + F34.0, according to ICD-10), who had previously a mild or asymptomatic coronavirus infection (group “COVID”), and 40 depressive patients, matched by sex, age, syndrome and the pre-treatment severity of depression (according to the total score of the Hamilton HDRS-17 scale), but not sick with COVID-19 (“non-COVID” group, The severity of suicidal intentions was quantified by the number of points of item 3 of the HDRS-17 scale. All patients underwent pre-treatment registration of the background EEG in a state of quiet wakefulness with eyes closed in 16 monopolar leads: F7, F3, F4, F8, T3, C3, Cz, C4, T4, T5, P3, Pz, P4, T6, O1 and O2. The analysis of the absolute EEG spectral power (SP) was carried out in 8 narrow frequency sub-bands. Statistical processing of the data obtained was carried out using the methods of descriptive statistics, comparison of means and correlation analysis of the IBM SPSS Statistics, v.22 software package.ResultsIn the “COVID” group, the mean number of points of item 3 of the HDRS-17 scale was slightly higher than in the “non-COVID” group (2.1 ± 1.5 and 1.8 ± 1.6, respectively), but these differences did not reach the level of statistical significance (p> 0.05). However, the structure of correlations between the values of this indicator of the severity of suicidal intentions and EEG parameters in the two groups turned out to be different. In the “COVID” group, the largest number of significantly (p<0.05) positive correlation coefficients was noted between the number of points of item 3 of the HDRS-17 scale and the SP values of slow-wave EEG components, e.g. theta2 sub-band (6-8 Hz) in leads F7, F3, F4, F8, T4, C3, C4, P3 and P4, as well as the delta sub-band (2-4 Hz) in leads F7 and P4. In the “non-COVID” group, the number of points of item 3 of the HDRS-17 scale positively correlated with the SP values of the alpha2 sub-band (9-11 Hz) in leads F7, F8, F4, C3, C4, T4, P4 and O2, as well as with SP values of the delta sub-band (2-4 Hz) in leads F7, F3 and C3.ConclusionsIn depressive patients who underwent COVID-19, the severity of suicidal intentions is associated with EEG signs of a more reduced functional state of the cerebral cortex, including the anterior regions, than in patients who did not have coronavirus infection.The study supported by the RSF grant No. 21-18-00129.Disclosure of InterestNone Declared

Comparison of flow characteristics behind squareback bluff-bodies with and without wheels

The wake dynamics of two referenced variations of the squareback Windsor model with and without wheels is numerically studied by performing improved delayed detached eddy simulation. Numerical assessments are validated against publicly available experimental data. The focus of this study is on the wake states influenced by the wheels and the thick oncoming floor boundary layer. Results show that the addition of the wheels significantly changes the aerodynamic forces, the underbody flow, and the wake topology. The wake bi-stability is also enhanced with wheels in place due to the increased curvature of lateral shear layers in the near wake. However, the bi-stable behavior is largely suppressed when immersed in a thick boundary layer. These alterations depend on the degree of interaction between the wake recirculation and the bottom flow, and such degree is strongly affected by the underbody flow momentum. The evolution of low-order flow organizations and complementary spectral analysis highlight the differences in the coherent dynamics of the wake. The finding of this present work suggests that the wake bi-stability behind the squareback body can exist not only for a simplified geometry but also for a more realistic car with wheels in real-world upstream conditions.

A Focus on Subtle Signs and Motor Behavior to Unveil Awareness in Unresponsive Brain-Impaired Patients: The Importance of Being Clinical.

Brain-injured patients in a state of cognitive motor dissociation (CMD) exhibit a lack of command following using conventional neurobehavioral examination tools but a high level of awareness and language processing when assessed using advanced imaging and electrophysiology techniques. Because of their behavioral unresponsiveness, patients with CMD may seem clinically indistinguishable from those with a true disorder of consciousness that affects awareness on a substantial level (coma, vegetative state/unresponsive wakefulness state, or minimally conscious state minus). Yet, by expanding the range of motor testing across limb, facial, and ocular motricity, we may detect subtle, purposeful movements even in the subset of patients classified as vegetative state/unresponsive wakefulness state. We propose the term of clinical CMD to describe patients showing these slight but determined motor responses and exhibiting a characteristic akinetic motor behavior as opposed to a pyramidal motor system behavior. These patients may harbor hidden cognitive capabilities and significant potential for a good long-term outcome. Indeed, we envision CMD as ranging from complete (no motor response) to partial (subtle clinical motor response) forms, falling within a spectrum of progressively better motor output in patients with considerable cognitive capabilities. In addition to providing a decisional flowchart, we present this novel approach to classification as a graphical model that illustrates the range of clinical manifestations and recovery trajectories fundamentally differentiating true disorders of consciousness from the spectrum of CMD.

Parabrachial tachykinin1-expressing neurons involved in state-dependent breathing control

Breathing is regulated automatically by neural circuits in the medulla to maintain homeostasis, but breathing is also modified by behavior and emotion. Mice have rapid breathing patterns that are unique to the awake state and distinct from those driven by automatic reflexes. Activation of medullary neurons that control automatic breathing does not reproduce these rapid breathing patterns. By manipulating transcriptionally defined neurons in the parabrachial nucleus, we identify a subset of neurons that express the Tac1, but not Calca, gene that exerts potent and precise conditional control of breathing in the awake, but not anesthetized, state via projections to the ventral intermediate reticular zone of the medulla. Activating these neurons drives breathing to frequencies that match the physiological maximum through mechanisms that differ from those that underlie the automatic control of breathing. We postulate that this circuit is important for the integration of breathing with state-dependent behaviors and emotions.

Reynolds number effect on the bistable dynamic of a blunt-base bluff body.

A three-dimensional blunt-base bluff body in a uniform flow is subjected to long-time stochastic dynamics of switching between two opposite wake states. This dynamic is investigated experimentally within the Reynolds number range Re ≃10^{4}-10^{5}. Long-time statistics coupled to a sensitivity analysis to the body attitude (defined as the pitch angle of the body with respect to the incoming flow) show that the wake switching rate decreases as Re increases. Equipping the body with passive roughness elements (turbulators) modifies the boundary layers before separation, seen as the inlet condition for the wake dynamic. Depending on their location and Re, the viscous sublayer length scale and the turbulent layer thickness can be modified independently. This sensitivity analysis to the inlet condition shows that a decrease of the viscous sublayer length scale at a given turbulent layer thickness leads to a decrease in the switching rate, whereas the modification of the turbulent layer thickness has almost no effect on the switching rate.

Propofol anesthesia-induced spatiotemporal changes in cortical activity with loss of external and internal awareness: An electrocorticography study

ObjectiveTo understand the underlying mechanism of consciousness, investigating spatiotemporal changes in the cortical activity during the induction phase of unconsciousness is important. Loss of consciousness induced by general anesthesia is not necessarily accompanied by a uniform inhibition of all cortical activities. We hypothesized that cortical regions involved in internal awareness would be suppressed after disruption of cortical regions involved in external awareness. Thus, we investigated temporal changes in cortex during induction of unconsciousness. MethodsWe recorded electrocorticography data of 16 epilepsy patients and investigated power spectral changes during induction phase from awake state to unconsciousness. Temporal changes were assessed at 1) the start point and 2) the interval of normalized time between start and end of power change (Δ tnormalized). ResultsWe found that the power increased at frequencies < 46 Hz, and decreased in range of 62–150 Hz, in global channels. In temporal changes of power change, superior parietal lobule and dorsolateral prefrontal cortex started to change early, but the changes were completed over a prolonged interval, whereas angular gyrus and associative visual cortex showed a delayed change and rapid completion. ConclusionsLoss of consciousness induced by general anesthesia results first from disrupted communication between self and external world, followed by disrupted communication within self, with decreased activities of superior parietal lobule and dorsolateral prefrontal cortex, and later, attenuated activities of angular gyrus. SignificanceOur findings provided neurophysiological evidence for the temporal changes in consciousness components induced by general anesthesia.

EEG Entropy in REM Sleep as a Physiologic Biomarker in Early Clinical Stages of Alzheimer's Disease.

Alzheimer's disease (AD) is associated with EEG changes across the sleep-wake cycle. As the brain is a non-linear system, non-linear EEG features across behavioral states may provide an informative physiologic biomarker of AD. Multiscale fluctuation dispersion entropy (MFDE) provides a sensitive non-linear measure of EEG information content across a range of biologically relevant time-scales. To evaluate MFDE in awake and sleep EEGs as a potential biomarker for AD. We analyzed overnight scalp EEGs from 35 cognitively normal healthy controls, 23 participants with mild cognitive impairment (MCI), and 19 participants with mild dementia due to AD. We examined measures of entropy in wake and sleep states, including a slow-to-fast-activity ratio of entropy (SFAR-entropy). We compared SFAR-entropy to linear EEG measures including a slow-to-fast-activity ratio of power spectral density (SFAR-PSD) and relative alpha power, as well as to cognitive function. SFAR-entropy differentiated dementia from MCI and controls. This effect was greatest in REM sleep, a state associated with high cholinergic activity. Differentiation was evident in the whole brain EEG and was most prominent in temporal and occipital regions. Five minutes of REM sleep was sufficient to distinguish dementia from MCI and controls. Higher SFAR-entropy during REM sleep was associated with worse performance on the Montreal Cognitive Assessment. Classifiers based on REM sleep SFAR-entropy distinguished dementia from MCI and controls with high accuracy, and outperformed classifiers based on SFAR-PSD and relative alpha power. SFAR-entropy measured in REM sleep robustly discriminates dementia in AD from MCI and healthy controls.

The gestational age significantly affects peripheral perfusion index value in low-altitude areas.

The gestational age significantly affects peripheral perfusion index value in low-altitude areas.

Remodeling in the AV block dog is essential for tolerating moderate treadmill activity.

A preclinical model standardized at different remodeling stages after AV block induction in awake state is suitable for the evaluation of improved cardiac devices. We studied exercise-induced cardiorespiratory parameters at three different timepoints after inducing AV block in dogs. Mongrel dogs (n=12) were placed on a treadmill with a 10% incline and performed a moderate exercise protocol (10-minute run at 6km/h). Dogs ran at sinus rhythm (SR), at two days (AVB2d, initiation of remodeling), three weeks (CAVB3) and six weeks (CAVB6, completed remodeling) after AV block. All dogs completed the exercise protocol at SR, CAVB3 and CAVB6, while 6/12 dogs at AVB2d failed to complete the exercise protocol. The atrial rate was higher at all AV block timepoints (126±20 to 141±19bpm at rest and 221±10 to 231±13bpm during exercise) compared to SR (100±29bpm at rest and 162±28bpm during exercise, p<0.05). Upon exercise, stroke volume increased from 66±15ml at SR, to 96±21ml at AVB2d (p<0.05), 91±13ml at CAVB3 (p<0.05) and 85±24ml at CAVB6 but failed to compensate for the AV block-induced bradycardia. Therefore, cardiac output was lower after AV block compared to SR. Exercising dogs at AVB2d showed most arrhythmic events, lowest VO2, and signs of desaturation and acidification in venous blood. Dogs with limited remodeling after AV block have a reduced exercise tolerance, which is reflected in changes in cardiorespiratory parameters.

Collective Behavior in Neuronal Networks with Electrical and Hybrid Synapses: Frequency Responses of Oscillations

We study synchronization through the combination of electrical synapse and hybrid synapse, and analyse frequency responses in a network constituted of two subnetworks (layers). We prove the onset of synchronization for two coupled nondelayed neurons when we set properly the coupling strength of electrical and chemical synapses, and neurotransmitter parameters of chemical synapse with constant initial conditions. The chemical synapse takes into consideration inhibitory and excitatory behaviors of the neuron. We further prove that for random initial conditions of few sets of identical nodes which constitute a network with two layers, global synchronization is possible for specific values of coupling strength and inner matrix configuration. To ensure great accuracy of the global synchronization, we add a controller and for all settings of electrical and chemical parameters, we always observe global synchronization in both layers and then, the associated network. Five different network topologies were used for the analysis. We finally verify the robustness of the global synchronization by using an external sinusoidal stimuli and observe that the control action is very powerful to maintain the global synchronization dynamic of the network. We observe equally that the instantaneous frequency can toggle between delta oscillations, awake state of the brain, up to gamma oscillations which are the frequencies of intensive activities of the brain.

Reynolds number effects on the bistable flows over a wavy circular cylinder

The wake of wavy cylinder has been shown to exhibit bistability. Depending on the initial condition, the final state of the wake can either develop into steady flow (state I), or periodic shedding (state II). In this paper, we perform numerical simulations to reveal the Reynolds number effects (Re=30 – 300) on these two wake states. With increasing Reynolds number, the steady vortical structures in state I wake sways back and forth in the spanwise direction, resulting in low-frequency fluctuations in drag forces, but not in lift. For state II, the increase in Reynolds number is associated with the emergence of another spectral peak in the lift coefficient. The secondary frequency is associated with highly three-dimensional vortical structures in the wake. For both states, the wakes transition to turbulent flows at higher Reynolds numbers, with the development of small-scale vortices. We further study the streamwise gust flows over the wavy cylinder. The time-varying inflow velocity results in a wide range of instantaneous Reynolds number spanning from the absolutely unstable flow regime to the bistable regime. Depending on the period of the inflow velocity variation, the wake perturbations grown at the absolutely unstable flow regime can be damped out in state I wake, or grow large enough to trigger the transition to state II, resulting in loss of flow control efficacy. The above analyses reveal novel flow physics of the bistable states at unexplored Reynolds numbers, and showcase the complex transition behavior between the two states in unsteady flows. The insights gained from this study improve the understanding of the wake dynamics of the wavy cylinder.

Construction and analysis of functional network of hemi-brain in patients with brain tumors before and after anesthesia based on resting-state functional magnetic resonance imaging

Objective: To construct and analyze the functional network changes of hemi-brain in patients with brain tumor before and after anesthesia by using resting state functional magnetic resonance imaging (rs-fMRI). Methods: A total of 18 right-handed patients were prospectively included (6 males and 12 females). The patients underwent glioma resection in Peking University International Hospital from December 2018 to December 2021, and age ranged from 20 to 65 (45.1±13.6) years, with American Society of Anesthesiologists (ASA) grade of Ⅰ-Ⅱ. MRI scans were performed while the patient was awake and at the depth of surgical anesthesia. The functional network of healthy lateral brain was constructed and analyzed by means of graph theory, and its global and local topological properties were calculated. Global topology attributes included global efficiency (Eg), local efficiency (Eloc), clustering parameters (Cp), length parameter of shortest path (Lp), and small world (SW). Topology attributes of nodes included node degree (ND), node efficiency (NE) and between centrality (BC). The global and nodal topological properties of the hemi-brain network were compared between patients with different hemispherical space occupying under wakefulness and anesthesia. Results: At the awake state, Eloc and Cp in the global topological attributes of hemi-brain network were 0.259±0.007 and 0.197±0.010, respectively, and decreased to 0.242±0.013 and 0.177±0.021, respectively after anesthesia, with statistically significant differences (all P<0.01). The topological attributes of the nodes in hemi-side brain showed that ND, NE and BC were increased in the default mode network-related brain regions, while NE and BC were decreased in the limbic system and subcortical structures. Eloc and Cp were 0.258±0.008 and 0.198±0.008 respectively in the patients with left hemisphere space occupying, and decreased to 0.241±0.011 and 0.177±0.015 respectively after anesthesia, with statistically significant differences (all P<0.01). However, only Eloc decreased in patients with right hemisphere space occupying after anesthesia, and Eloc was 0.260±0.006 and 0.243±0.016 respectively when awake and after anesthesia, with statistically significant differences (P<0.05). The topological attributes of nodes in patients with space occupying in different cerebral hemispheres showed bidirectional changes after anesthesia, and patients with space occupying in the left cerebral hemisphere were more likely to be widely affected after anesthesia. The effects of anesthetic drugs may show hemispheric laterality. If the tumor was in the dominant hemisphere, the compensatory function of the dominant side was more likely to be damaged. Conclusions: During anesthesia-induced loss of consciousness in patients with brain tumors, both the ability to integrate information and the functional connections between local regions are weakened, and some brain regions have functional connection reorganization. The changes of brain network after anesthesia are bidirectional regulation.

Inhibition is a prevalent mode of activity in the neocortex around awake hippocampal ripples in mice.

Coordinated peri-ripple activity in the hippocampal-neocortical network is essential for mnemonic information processing in the brain. Hippocampal ripples likely serve different functions in sleep and awake states. Thus, the corresponding neocortical activity patterns may differ in important ways. We addressed this possibility by conducting voltage and glutamate wide-field imaging of the neocortex with concurrent hippocampal electrophysiology in awake mice. Contrary to our previously published sleep results, deactivation and activation were dominant in post-ripple neocortical voltage and glutamate activity, respectively, especially in the agranular retrosplenial cortex (aRSC). Additionally, the spiking activity of aRSC neurons, estimated by two-photon calcium imaging, revealed the existence of two subpopulations of excitatory neurons with opposite peri-ripple modulation patterns: one increases and the other decreases firing rate. These differences in peri-ripple spatiotemporal patterns of neocortical activity in sleep versus awake states might underlie the reported differences in the function of sleep versus awake ripples.