Language：English   Publisher：Medicine (United States)  

Intraoperative hypotension (IOH) or highly invasive surgery adversely affects postoperative clinical outcomes. It is, however, unclear whether IOH affects postoperative acute kidney injury (AKI) depending on the invasiveness of abdominal surgery. We speculated that IOH in highly invasive abdominal surgery is a significant risk factor for postoperative AKI. We retrospectively reviewed the data of 448 patients who underwent abdominal surgery. Patients were divided into 3 groups: highly (such as pancreaticoduodenectomy and hepatectomy), moderately (open abdominal surgery), and minimally (laparoscopic surgery) invasive surgeries. The association between the time-weighted average (TWA) of mean arterial pressure (MAP) values (≤60 and ≤ 55 mm Hg) and AKI occurrences in each group was assessed. Postoperative AKI occurred after highly, moderately, and minimally invasive surgeries in 33 of 222 (14.9%), 14 of 110 (12.7%), and 12 of 116 (10.3%) cases, respectively (P = .526). The median [interquartile range] of TWA-MAP ≤ 60 mm Hg, as an IOH parameter, was 0.94 [0.33-2.08] mm Hg in highly, 0.54 [0.16-1.46] mm Hg in moderately, and 0.14 [0.03-0.57] mm Hg in minimally invasive surgeries (P < 0001). In addition, there was a significant association between TWA-MAP and AKI in highly invasive surgery, unlike in moderately and minimally invasive surgery, with adjusted odds ratios (95% confidence interval) for TWA-MAP ≤ 60 and ≤ 55 mm Hg associated with AKI of 1.23 [1.00-1.52] (P = .049) and 1.55 [1.02-2.36] (P = .041), respectively. Intraoperative MAP ≤ 60 mm Hg in highly invasive abdominal surgery is associated with postoperative AKI, compared to moderately and minimally invasive surgeries. Additionally, low MAP thresholds in highly invasive surgery increase postoperative AKI risk.

DOI： 10.1097/MD.0000000000036465

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Publisher：克誠堂出版  

DOI： 10.18916/masui.2023130022

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

Prepulse inhibition (PPI) is sensory suppression whose mechanism (i.e., whether PPI originates from specific inhibitory mechanisms) remains unclear. In this study, we applied the combination of short-latency PPI and long-latency paired pulse suppression in 17 healthy subjects using magnetoencephalography to investigate the mechanisms of sensory suppression. Repeats of a 25-ms pure tone without a blank at 800 Hz and 70 dB were used for a total duration of 1600 ms. To elicit change-related cortical responses, the sound pressure of two consecutive tones in this series at 1300 ms was increased to 80 dB (Test). For the conditioning stimuli, the sound pressure was increased to 73 dB at 1250 ms (Pre 1) and 80 dB at 700 ms (Pre 2). Six stimuli were randomly presented as follows: (1) Test alone, (2) Pre 1 alone, (3) Pre 1 + Test, (4) Pre 2 + Test, (5) Pre 2 + Pre 1, and (6) Pre 2 + Pre 1 + Test. The inhibitory effects of the conditioning stimuli were evaluated using N100m/P200m components. The results showed that both Pre 1 and Pre 2 significantly suppressed the Test response. Moreover, the inhibitory effects of Pre 1 and Pre 2 were additive. However, when both prepulses were present, Pre 2 significantly suppressed the Pre 1 response, suggesting that the Pre 1 response amplitude was not a determining factor for the degree of suppression. These results suggested that the suppression originated from a specific inhibitory circuit independent of the excitatory pathway.

DOI： 10.1016/j.neuroscience.2022.11.016

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Language：English   Publishing type：Research paper (scientific journal)  

The 40-Hz auditory steady-state response (ASSR) has received special attention as an index of gamma oscillations owing to its association with various neuropsychiatric disorders including schizophrenia. When a periodic stimulus is presented, oscillatory responses are often elicited not only at the stimulus frequency, but also at its harmonic frequencies. However, little is known about the effect of 40-Hz subharmonic stimuli on the activity of the 40-Hz ASSR. In the present magnetoencephalography study, we focused on the nature of oscillation harmonics and examined oscillations in a wide frequency range using a time-frequency analysis during the 6.67-, 8-, 10-, 13.3-, 20-, and 40-Hz auditory stimuli in 23 healthy subjects. The results suggested that the 40-Hz ASSR represents activation of a specific circuit tuned to this frequency. Particularly, oscillations elicited by 13.3- and 20-Hz stimuli exhibited significant enhancement at 40 Hz without changing those at the stimulus frequency. In addition, it was found that there was a non-linear response to stimulation in the beta band. We also demonstrated that the inhibition of beta to low-gamma oscillations by the 40-Hz circuit contributed to the violation of the rule that harmonic oscillations gradually decrease at higher frequencies. These findings can advance our understanding of oscillatory abnormalities in patients with schizophrenia in the future.

DOI： 10.3389/fnins.2023.1127040

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Language：English   Publishing type：Research paper (scientific journal)  

Despite the clinical significance of prepulse inhibition (PPI), the mechanisms are not well understood. Herein, we present our investigation of PPI in the R1 component of electrically induced blink reflexes. The effect of a prepulse was explored with varying prepulse-test intervals (PTIs) of 20-600 ms in 4 females and 12 males. Prepulse-test combinations included: stimulation of the supraorbital nerve (SON)-SON (Exp 1), sound-sound (Exp 2), the axon of the facial nerve-SON (Exp 3), sound-SON (Exp 4), and SON-SON with a long trial-trial interval (Exp 5). Results showed that 1) leading weak SON stimulation reduced SON-induced ipsilateral R1 with a maximum effect at a PTI of 140 ms, 2) the sound-sound paradigm resulted in a U-shaped inhibition time course of the auditory startle reflex (ASR) peaking at 140 ms PTI, 3) facial nerve stimulation showed only a weak effect on R1, 4) a weak sound prepulse facilitated R1 but strongly inhibited SON-induced late blink reflexes (LateR) with a similar U-shaped curve, and 5) LateR in Exp 5 was almost completely absent at PTIs longer than 80 ms. These results indicate that the principal sensory nucleus is responsible for R1 PPI. Inhibition of ASR or LateR occurs at a point in the startle reflex circuit where auditory and somatosensory signals converge. Although the two inhibitions are different in location, their similar time courses suggest similar neural mechanisms. As R1 has a simple circuit and is stable, R1 PPI helps to clarify PPI mechanisms.SIGNIFICANCE STATEMENT:Prepulse inhibition (PPI) is a phenomenon in which the startle response induced by a startle stimulus is suppressed by a preceding non-startle stimulus. This study demonstrated that the R1 component of the trigeminal blink reflex shows clear PPI despite R1 generation within a circuit consisting of the trigeminal and facial nuclei, without startle reflex circuit involvement. Thus, PPI is not specific to the startle reflex. In addition, PPI of R1, the auditory startle reflex, and the trigeminal late blink reflex showed similar time courses in response to the prepulse-test interval, suggesting similar mechanisms regardless of inhibition site. R1 PPI, in conjunction with other paradigms with different prepulse-test combinations, would increase understanding of underlying mechanisms.

DOI： 10.1523/JNEUROSCI.1468-22.2022

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Publisher：克誠堂出版(株)  

DOI： 10.18916/j01397.2023016077

CiNii Research

Language：Japanese   Publisher：The Japanese Society of Intensive Care Medicine  

DOI： 10.3918/jsicm.29_601

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

Gamma oscillations have received considerable attention owing to their association with cognitive function and various neuropsychiatric disorders. However, interactions of gamma oscillations at different frequency bands in humans remain unclear. In the present magnetoencephalographic study, brain oscillations in a wide frequency range were examined using a time-frequency analysis during the 20-, 30-, 40-, and 50-Hz auditory stimuli in 21 healthy subjects. First, dipoles for auditory steady-state response (ASSR) were estimated and interaction among oscillations at 10-60 Hz was examined using the source strength waveforms. Results showed the suppression of ongoing low-gamma oscillations at approximately 30 Hz during stimulation at 40 Hz. Second, multi-dipole analyses suggested that the main dipole for ASSR and dipoles for suppressed low-frequency gamma oscillations were distinct. Third, an all-sensor analysis was performed to clarify the distribution of the 40-Hz ASSR and suppression of low-frequency gamma oscillations. Notably, the area of suppression surrounded the center of the 40-Hz ASSR and showed a trend of extending to the vertex, indicating that different groups of neurons were responsible for these two gamma oscillations and that the 40-Hz oscillation circuit have specific inhibitory innervation to the low-gamma circuit.

DOI： 10.1093/cercor/bhab381

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

i-gel™ is a supraglottic airway device widely used for airway management during general anesthesia as an alternative to tracheal intubation. It sometimes results in a sore throat postoperatively; however, the risk factors for a postoperative sore throat caused by i-gel remain unclear. Here, we clarify the risk factors for a postoperative sore throat associated with i-gel insertion. We retrospectively reviewed the data of 426 adult patients who received general anesthesia with i-gel at our institution from January 2018 to December 2019. The incidence of postoperative sore throat and intraoperative data (size of i-gel, number of insertion attempts, total insertion time, and dose of the neuromuscular blocker and opioid) were evaluated. Logistic regression analysis was performed to identify the risk factors. Postoperative sore throat following i-gel insertion occurred in 24/426 patients (5.6%). The insertion time was significantly associated with the incidence of postoperative sore throat in the univariate analysis, but not in the multivariate analysis (P=0.519). Increased doses of neuromuscular blockers before i-gel insertion (odds ratio [OR], 5.46; 95% confidence interval [CI], 1.50-19.80; P=0.001) and reduced doses of intraoperative fentanyl (OR, 0.51; 95% CI, 0.28-0.93; P=0.028) were risk factors in the univariate and multivariate analyses. In the subgroup that used neuromuscular blockers before i-gel insertion, only an increased dose of neuromuscular blocker (OR, 17.2; 95%, CI 1.06-280; P=0.046) was an associated risk factor in the univariate and multivariate analyses. Overall, increased doses of neuromuscular blockers before i-gel insertion could contribute to the development of postoperative sore throat.

DOI： 10.18999/nagjms.84.2.319

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PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Paired pulse suppression is an electrophysiological method used to evaluate sensory suppression and often applied to patients with psychiatric disorders. However, it remains unclear whether the suppression comes from specific inhibitory mechanisms, refractoriness, or fatigue. In the present study, to investigate mechanisms of suppression induced by an auditory paired pulse paradigm in 19 healthy subjects, magnetoencephalography was employed. The control stimulus was a train of 25-ms pure tones of 65 dB SPL for 2500 ms. In order to evoke a test response, the sound pressure of two consecutive tones at 2200 ms in the control sound was increased to 80 dB (Test stimulus). Similar sound pressure changes were also inserted at 1000 (CS2) and 1600 (CS1) ms as conditioning stimuli. Four stimulus conditions were used; (1) Test alone, (2) Test + CS1, (3) Test + CS1 + CS2, and (4) Test + CS2, with the four sound stimuli randomly presented and cortical responses averaged at least 100 times for each condition. The baseline-to-peak and peak-to-peak amplitudes of the P50m, N100m, and P200m components of the test response were compared among the four conditions. In addition, the response to CS1 was compared between conditions (2) and (3). The results showed significant test response suppression by CS1. While the response to CS1 was significantly suppressed when CS2 was present, it did not affect suppression of the test response by CS1. It was thus suggested that the amplitude of the response to a conditioning stimulus is not a factor to determine the inhibitory effects of the test response, indicating that suppression is due to an external influence on the excitatory pathway.

DOI： 10.1007/s10548-021-00878-6

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

Language：Japanese   Publisher：(公社)日本精神神経学会  

Language：English   Publishing type：Research paper (scientific journal)  

Although conditioned pain modulation (CPM) is considered to represent descending pain inhibitory mechanisms triggered by noxious stimuli applied to a remote area, there have been no previous studies comparing CPM between pain and tactile systems. In this study, we compared CPM between the two systems objectively using blink reflexes. Intra-epidermal electrical stimulation (IES) and transcutaneous electrical stimulation (TS) were applied to the right skin area over the supraorbital foramen to evoke a nociceptive or a non-nociceptive blink reflex, respectively, in 15 healthy males. In the test session, IES or TS were applied six times and subjects reported the intensity of each stimulus on a numerical rating scale (NRS). Blink reflexes were measured using electromyography (R2). The first and second sessions were control sessions, while in the third session, the left hand was immersed in cold water at 10 °C as a conditioning stimulus. The magnitude of the R2 blink and NRS scores were compared among the sessions by 2-way ANOVA. Both the NRS score and nociceptive R2 were significantly decreased in the third session for IES, with a significant correlation between the two variables; whereas, TS-induced non-nociceptive R2 did not change among the sessions. Although the conditioning stimulus decreased the NRS score for TS, the CPM effect was significantly smaller than that for IES (p = 0.002). The present findings suggest the presence of a pain-specific CPM effect to a heterotopic noxious stimulus.

DOI： 10.1016/j.neuroscience.2021.06.019

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Language：English   Publishing type：Research paper (scientific journal)  

Sensory processing is disrupted in several psychiatric disorders, including schizophrenia, bipolar disorder, and autism spectrum disorder. In this review, we focus on the electrophysiological auditory steady-state response (ASSR) driven by high-frequency stimulus trains as an index for disease-associated sensory processing deficits. The ASSR amplitude is suppressed within the gamma band (≥30 Hz) among these patients, suggesting an imbalance between GABAergic and N-methyl-D-aspartate (NMDA) receptor-mediated neurotransmission. The reduced power and synchronization of the 40-Hz ASSR are robust in patients with schizophrenia. In recent years, similar ASSR deficits at gamma frequencies have also been reported in patients with bipolar disorder and autism spectrum disorder. We summarize ASSR abnormalities in each of these psychiatric disorders and suggest that the observed commonalities reflect shared pathophysiological mechanisms. We reviewed studies on phase resetting in which a salient sensory stimulus affects ASSR. Phase resetting induces the reduction of both the amplitude and phase of ASSR. Moreover, phase resetting is also affected by rare auditory stimulus patterns or superimposed stimuli of other modalities. Thus, sensory memory and multisensory integration can be investigated using phase resetting of ASSR. Here, we propose that ASSR amplitude, phase, and resetting responses are sensitive indices for investigating sensory processing dysfunction in psychiatric disorders.

DOI： 10.3389/fpsyt.2021.644541

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Language：Japanese   Publisher：(一社)日本臨床神経生理学会  

J-GLOBAL

J-GLOBAL

Language：Japanese   Publisher：(一社)日本心臓血管麻酔学会