A low-activity cortical network selectively encodes syntax.

Syntax, the abstract structure of language, is a hallmark of human cognition. Despite its importance, its neural underpinnings remain obscured by inherent limitations of non-invasive brain measures and a near total focus on comprehension paradigms. Here, we address these limitations with high-resolution neurosurgical recordings (electrocorticography) and a controlled sentence production experiment. We uncover three syntactic networks that are broadly distributed across traditional language regions, but with focal concentrations in middle and inferior frontal gyri. In contrast to previous findings from comprehension studies, these networks process syntax mostly to the exclusion of words and meaning, supporting a cognitive architecture with a distinct syntactic system. Most strikingly, our data reveal an unexpected property of syntax: it is encoded independent of neural activity levels. We propose that this "low-activity coding" scheme represents a novel mechanism for encoding information, reserved for higher-order cognition more broadly.

Evoking artificial speech perception through invasive brain stimulation for brain-computer interfaces: current challenges and future perspectives.

Encoding artificial perceptions through brain stimulation, especially that of higher cognitive functions such as speech perception, is one of the most formidable challenges in brain-computer interfaces (BCI). Brain stimulation has been used for functional mapping in clinical practices for the last 70 years to treat various disorders affecting the nervous system, including epilepsy, Parkinson's disease, essential tremors, and dystonia. Recently, direct electrical stimulation has been used to evoke various forms of perception in humans, ranging from sensorimotor, auditory, and visual to speech cognition. Successfully evoking and fine-tuning artificial perceptions could revolutionize communication for individuals with speech disorders and significantly enhance the capabilities of brain-computer interface technologies. However, despite the extensive literature on encoding various perceptions and the rising popularity of speech BCIs, inducing artificial speech perception is still largely unexplored, and its potential has yet to be determined. In this paper, we examine the various stimulation techniques used to evoke complex percepts and the target brain areas for the input of speech-like information. Finally, we discuss strategies to address the challenges of speech encoding and discuss the prospects of these approaches.

Consistent spectro-spatial features of human ECoG successfully decode naturalistic behavioral states.

Objective: Understanding the neural correlates of naturalistic behavior is critical for extending and confirming the results obtained from trial-based experiments and designing generalizable brain-computer interfaces that can operate outside laboratory environments. In this study, we aimed to pinpoint consistent spectro-spatial features of neural activity in humans that can discriminate between naturalistic behavioral states. Approach: We analyzed data from five participants using electrocorticography (ECoG) with broad spatial coverage. Spontaneous and naturalistic behaviors such as "Talking" and "Watching TV" were labeled from manually annotated videos. Linear discriminant analysis (LDA) was used to classify the two behavioral states. The parameters learned from the LDA were then used to determine whether the neural signatures driving classification performance are consistent across the participants. Main results: Spectro-spatial feature values were consistently discriminative between the two labeled behavioral states across participants. Mainly, θ, α, and low and high γ in the postcentral gyrus, precentral gyrus, and temporal lobe showed significant classification performance and feature consistency across participants. Subject-specific performance exceeded 70%. Combining neural activity from multiple cortical regions generally does not improve decoding performance, suggesting that information regarding the behavioral state is non-additive as a function of the cortical region. Significance: To the best of our knowledge, this is the first attempt to identify specific spectro-spatial neural correlates that consistently decode naturalistic and active behavioral states. The aim of this work is to serve as an initial starting point for developing brain-computer interfaces that can be generalized in a realistic setting and to further our understanding of the neural correlates of naturalistic behavior in humans.

Dependence of rhythmic activity and oddball effects in the rat cortex on the depth of sedation during dissociative anesthesia.

The reactions to novelty manifesting in mismatch negativity in the rat brain were studied. During dissociative anesthesia, mismatch negativity-like waves were recorded from the somatosensory cortex using an epidural 32-electrode array. Experimental animals: 7 wild-type Wistar rats and 3 transgenic rats. During high-dose anesthesia, deviant 1,500 Hz tones were presented randomly among many standard 1,000 Hz tones in the oddball paradigm. "Deviant minus standard_before_deviant" difference waves were calculated using both the classical method of Naatanen and method of cross-correlation of sub-averages. Both methods gave consistent results: an early phasic component of the N40 and later N100 to 200 (mismatch negativity itself) tonic component. The gamma and delta rhythms power and the frequency of down-states (suppressed activity periods) were assessed. In all rats, the amplitude of tonic component grew with increasing sedation depth. At the same time, a decrease in gamma power with a simultaneous increase in delta power and the frequency of down-states. The earlier phasic frontocentral component is associated with deviance detection, while the later tonic one over the auditory cortex reflects the orienting reaction. Under anesthesia, this slow mismatch negativity-like wave most likely reflects the tendency of the system to respond to any influences with delta waves, K-complexes and down-states, or produce them spontaneously.

Increasing serum complement component 1q is associated with worse prognosis in advanced non-small cell lung cancer treated with immune checkpoint inhibitors: a single-center, retrospective study.

Background: There is a lack of readily available clinical markers of non-small cell lung cancer (NSCLC) immunotherapy efficacy. Previous studies have found that overexpressed complement component 1q (C1q) promotes macrophage M2 polarization and an immunosuppressive tumor microenvironment. This study aimed to evaluate the association between serum C1q and the efficacy of immune checkpoint inhibitors (ICIs) in patients with advanced NSCLC. Methods: A total of 168 patients with advanced NSCLC who received ICIs in the Renmin Hospital of Wuhan University were included in this study. Serum C1q levels were collected before and 3 weeks after immunotherapy treatment, together with other data on clinical and demographic characteristics. The primary outcome was overall survival (OS) (months from first dose of ICIs to death, censored at date of last follow-up). Secondary outcome was progression-free survival (PFS) [defined as months from first dose of ICIs to clinical or radiographic progression by Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) or death, censored at date of last follow-up] and objective response rate (ORR) which was defined as rate of complete response (CR) or partial response (PR) at best response by RECIST 1.1. Results: A total of 168 patients were included in this study, including 127 males (75.60%) and 41 females (24.40%). Thirty-nine patients achieved objective response (2 CR, 37 PR), and 111 patients (66.07%) had stable disease (SD) as best response. The ORR was 23.21% and the disease control rate was 89.28%. The upward trends of serum C1q levels between baseline and post-treatment were strongly associated with the shorter PFS [hazard ratio (HR) =1.554, 95% confidence interval (CI): 1.07-2.10, P=0.01] and OS (HR =1.444, 95% CI: 1.01-1.98, P=0.03). Moreover, taking the median OS 18.9 months as the cut-off of prognosis, receiver operating characteristic (ROC) analysis showed that serum baseline C1q yielded an area under the ROC curve of 0.785 (95% CI: 0.711-0.869). The optimal serum baseline C1q cut-off point to predict immunotherapy prognosis was 216.2 mg/L. Conclusions: These findings suggested that elevated serum C1q after ICIs treatment was related to a worse prognosis in NSCLC. Monitoring the baseline and dynamic data of C1q during hospitalization showed the potential to predict the prognosis of NSCLC patients.

Stability of ECoG high gamma signals during speech and implications for a speech BCI system in an individual with ALS: a year-long longitudinal study.

Objective.Speech brain-computer interfaces (BCIs) have the potential to augment communication in individuals with impaired speech due to muscle weakness, for example in amyotrophic lateral sclerosis (ALS) and other neurological disorders. However, to achieve long-term, reliable use of a speech BCI, it is essential for speech-related neural signal changes to be stable over long periods of time. Here we study, for the first time, the stability of speech-related electrocorticographic (ECoG) signals recorded from a chronically implanted ECoG BCI over a 12 month period.Approach.ECoG signals were recorded by an ECoG array implanted over the ventral sensorimotor cortex in a clinical trial participant with ALS. Because ECoG-based speech decoding has most often relied on broadband high gamma (HG) signal changes relative to baseline (non-speech) conditions, we studied longitudinal changes of HG band power at baseline and during speech, and we compared these with residual high frequency noise levels at baseline. Stability was further assessed by longitudinal measurements of signal-to-noise ratio, activation ratio, and peak speech-related HG response magnitude (HG response peaks). Lastly, we analyzed the stability of the event-related HG power changes (HG responses) for individual syllables at each electrode.Main Results.We found that speech-related ECoG signal responses were stable over a range of syllables activating different articulators for the first year after implantation.Significance.Together, our results indicate that ECoG can be a stable recording modality for long-term speech BCI systems for those living with severe paralysis.Clinical Trial Information.ClinicalTrials.gov, registration number NCT03567213.

Bellmunt risk score as a survival predictor in patients with metastatic castration-resistant prostate cancer.

BACKGROUND: The prognosis of metastatic castration-resistant prostate cancer (mCRPC) is influenced by numerous individual factors. Despite various proposed prognostic models, the clinical application of these remains limited, probably due to complexity. Our study aimed to evaluate the predictive value of the Bellmunt risk score, which is well-known for urothelial carcinoma and easily assessed, in mCRPC patients. METHODS: The Bellmunt risk score was calculated from three risk factors (Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≥1, serum hemoglobin <10 g/dL, presence of liver metastases) in 125 patients who received first-line mCRPC treatment between 2005 and 2023. In addition, a modified score was established (one point each for hemoglobin <10 g/dL and the presence of liver metastases added to the ECOG PS). Associations with overall survival (OS) under first- and second-line therapy were tested using Cox regression analyzes, log-rank tests, concordance index (C-index) and time-dependent receiver operating characteristic. RESULTS: There is a significant correlation between the level of the Bellmunt risk score and shorter OS (hazard ratio: 3.23, 95% confidence interval: 2.06-5.05; log-rank p < 0.001; C-index: 0.724). The semi-quantitative modified risk score showed even better prognostic discrimination (log-rank p < 0.001, C-index: 0.764). The score and its dynamics were also predictive in the second-line setting (log-rank p < 0.001 and = 0.01; C-index: 0.742 and 0.595). CONCLUSIONS: The Bellmunt risk score is easy to assess and provides useful prognostic information in mCRPC, and can support physicians in their treatment decisions.

Simulation-Informed Power Budget Estimate of a Fully-Implantable Brain-Computer Interface.

This study aims to estimate the maximum power consumption that guarantees a thermally safe operation for a titanium-enclosed chest wall unit (CWU) subcutaneously implanted in the pre-pectoral area. This unit is a central piece of an envisioned fully-implantable bi-directional brain-computer interface (BD-BCI). To this end, we created a thermal simulation model using the finite element method implemented in COMSOL. We also performed a sensitivity analysis to ensure that our predictions were robust against the natural variation of physiological and environmental parameters. Based on this analysis, we predict that the CWU can consume between 378 and 538 mW of power without raising the surrounding tissue's temperature above the thermal safety threshold of 2  ∘ C. This power budget should be sufficient to power all of the CWU's basic functionalities, which include training the decoder, online decoding, wireless data transmission, and cortical stimulation. This power budget assessment provides an important specification for the design of a CWU-an integral part of a fully-implantable BD-BCI system.

The neurophysiological effect of mild hypothermia in gyrencephalic brains submitted to ischemic stroke and spreading depolarizations.

Objective: Characterize the neurophysiological effects of mild hypothermia on stroke and spreading depolarizations (SDs) in gyrencephalic brains. Methods: Left middle cerebral arteries (MCAs) of six hypothermic and six normothermic pigs were permanently occluded (MCAo). Hypothermia began 1 h after MCAo and continued throughout the experiment. ECoG signals from both frontoparietal cortices were recorded. Five-minute ECoG epochs were collected 5 min before, at 5 min, 4, 8, 12, and 16 h after MCAo, and before, during, and after SDs. Power spectra were decomposed into fast (alpha, beta, and gamma) and slow (delta and theta) frequency bands. Results: In the vascular insulted hemisphere under normothermia, electrodes near the ischemic core exhibited power decay across all frequency bands at 5 min and the 4th hour after MCAo. The same pattern was registered in the two furthest electrodes at the 12th and 16th hour. When mild hypothermia was applied in the vascular insulted hemispheres, the power decay was generalized and seen even in electrodes with uncompromised blood flow. During SD analysis, hypothermia maintained increased delta and beta power during the three phases of SDs in the furthest electrode from the ischemic core, followed by the second furthest and third electrode in the beta band during preSD and postSD segments. However, in hypothermic conditions, the third electrode showed lower delta, theta, and alpha power. Conclusion: Mild hypothermia attenuates all frequency bands in the vascularly compromised hemisphere, irrespective of the cortical location. During SD formation, it preserves power spectra more significantly in electrodes further from the ischemic core.

Prevalence and co-incidence of geriatric syndromes according to the ECOG performance status in older cancer patients.

Background: Geriatric syndromes may be more common in older cancer patients than in those without cancer. Geriatric syndromes can cause poor clinical outcomes. The Eastern Cooperative Oncology Group Performance Status (ECOG-PS) is often used as a clinically reported functional status score in oncology practice. Methods: Our study was designed as a cross-sectional study and included 218 older cancer patients. This study aimed to determine the prevalence and relationship of geriatric syndromes according to the ECOG-PS in older cancer patients. Results: The mean age of 218 participants was 73.0 ± 5.6 years, with 47.7% being women and 52.3% men in our study. ECOG-PS 0, 1, and 2 groups contained 51, 39, and 10% of the patients, respectively. The mean number of geriatric syndromes in the ECOG 0, 1, and 2 groups was 2.3 ± 2.2, 4.3 ± 2.4, and 5.7 ± 2.1, respectively (p < 0.001). After adjusting for age and sex, it was determined that dynapenia was 2.9 times, probable sarcopenia was 3.5 times, frailty was 4.2 times, depression was 2.6 times, malnutrition was 3.3 times, insomnia 2 was.2 times, falls was 2.5 times, and the risk of falling (TUG) was 2.4 times more likely in those with ECOG-PS 1 compared to those with ECOG-PS 0. In addition, it was found that dynapenia was 6 times, probable sarcopenia was 6.8 times, frailty was 10.8 times, depression was 3.3 times, malnutrition was 6.3 times, the risk of falling (Tinnetti Balance) was 28 times, and the risk of falling (TUG) was 13.6 times more likely in those with ECOG-PS 2 compared to those with ECOG-PS 0. Conclusion: Our study found that the prevalence of geriatric syndromes increased as the ECOG-PS increased. Geriatric syndromes and their co-incidence were common in older cancer patients, even in normal performance status. Oncologists should incorporate geriatric syndromes into the decision-making process of cancer treatment to maximize the impact on clinical outcomes in older patients with cancer.

Relationship between fear of progression and symptom burden, disease factors and social/family factors in patients with stage-IV breast cancer in Shandong, China.

OBJECTIVE: To assess fear of progression (FoP)'s relationship with symptom burden and disease and social/family factors, as well as, determine the status of FoP in women with stage-IV breast cancer in Shandong, China. METHODS: Two hundred and sixteen women were recruited from the department of breast cancer internal medicine, Shandong Cancer Hospital and Institute. Data for this observational study were collected between October 2020 and January 2021 using the MD Anderson Symptom Inventory, the Fear of Progression Questionnaire-Short Form (FoP-Q-SF) and a participant information scale. SPSS 23.0 was used for statistical analysis. RESULTS: After excluding invalid responses, the data of 200 participants were analysed. The average total FoP-Q-SF score was 29.39 ± 9.39 (95% confidence interval, 21.81-27.64). The FoP level among the participants was relatively low. For disease and social/family factors, FoP statistically significantly differed by satisfaction with family emotional support and the Eastern Cooperative Oncology Group (ECOG) score. The ECOG score was positively correlated with FoP. Furthermore, symptom burden was positively correlated with FoP. CONCLUSIONS: Among patients with stage-IV breast cancer, satisfaction with family emotional support, ECOG score and symptom burden play key roles in FoP. Interventions, including providing appropriate emotional support from family, improving physical fitness and relieving symptom burden, must be considered in future studies, which may improve patients' overall physical and mental status and provide a supportive therapeutic environment.

Integrating Patient-Reported Outcomes Into Prognostication in Gastroesophageal Cancer: Results of a Population-Based Retrospective Cohort Analysis.

BACKGROUND: Patient-reported outcomes measures (PROM) are self-reflections of an individual's physical functioning and emotional well-being. The Edmonton Symptom Assessment Scale (ESAS) is a simple and validated PRO tool of 10 common symptoms and a patient-reported functional status (PRFS) measure. The prognostic value of this tool is unknown in patients with gastroesophageal cancer (GEC). In this study, we examined the association between the ESAS score and overall survival (OS) in patients with GEC, the prognostication difference between ESAS and Eastern Cooperative Oncology Group (ECOG), and assessed the correlation between PRFS and the physician-reported ECOG performance status (PS). METHODS: The study was a retrospective cohort study of 211 patients with GEC with localized (stages I-III) and metastatic disease who completed at least one baseline ESAS prior to treatment. Patients were grouped into 3 cohorts based on ESAS score. OS was assessed using the Kaplan-Meier method, and the concordance index (c-index) was calculated for ESAS and physician-reported ECOG. The agreement between PRFS and physician-ECOG was also assessed. RESULTS: In total, 211 patients were included. The median age was 60.8 years; 90% of patients were ECOG PS 0-1; 38% of patients were stages I-III, while 62% were de novo metastatic patients. Median OS in low, moderate, high symptom burden (SB) patients' cohorts was 19.17 m, 16.39 mm, and 12.68 m, respectively (P < .04). The ability to predict death was similar between physician-ECOG and ESAS (c-index 0.56 and 0.5753, respectively) and PRFS and physician-ECOG (c-index of 0.5615 and 0.5545, respectively). The PS agreement between patients and physicians was 50% with a weighted Kappa of 0.27 (95% CI: 0.17-0.38). CONCLUSION: Patient's SB seems to carry a prognostic significance. ESAS and physician-reported ECOG exhibit comparable prognostic values. Physicians and patients can frequently have divergent opinions on PS. ESAS takes a patient-centered approach and should be encouraged in practice among patients with GEC as an additional tool for prognostication.

Auditory prediction errors in sound frequency and duration generated different cortical activation patterns in the human brain: an ECoG study.

Sound frequency and duration are essential auditory components. The brain perceives deviations from the preceding sound context as prediction errors, allowing efficient reactions to the environment. Additionally, prediction error response to duration change is reduced in the initial stages of psychotic disorders. To compare the spatiotemporal profiles of responses to prediction errors, we conducted a human electrocorticography study with special attention to high gamma power in 13 participants who completed both frequency and duration oddball tasks. Remarkable activation in the bilateral superior temporal gyri in both the frequency and duration oddball tasks were observed, suggesting their association with prediction errors. However, the response to deviant stimuli in duration oddball task exhibited a second peak, which resulted in a bimodal response. Furthermore, deviant stimuli in frequency oddball task elicited a significant response in the inferior frontal gyrus that was not observed in duration oddball task. These spatiotemporal differences within the Parasylvian cortical network could account for our efficient reactions to changes in sound properties. The findings of this study may contribute to unveiling auditory processing and elucidating the pathophysiology of psychiatric disorders.

Clinical predictors of response to single­agent immune checkpoint inhibitors in chemotherapy­pretreated non­small cell lung cancer.

Single-agent immune checkpoint inhibitors (ICIs) are the standard option for chemotherapy-pretreated metastatic non-small cell lung cancer (NSCLC), however only a subset of patients responds to this treatment. The present study aimed at the development of a tool for personalized prediction of the efficacy of ICIs. The study included 181 epidermal growth factor receptor/anaplastic lymphoma kinase-negative patients with metastatic NSCLC receiving single-agent ICI in the second or later line of therapy. For the comparison, a total of 63 metastatic patients with NSCLC treated by chemotherapy were also analyzed. Multivariate analysis revealed that Eastern Cooperative Oncology Group performance status (ECOG PS) ≥2, never-smoking status and the baseline neutrophil-to-lymphocyte ratio (NLR) ≥4.3 were associated with reduced progression-free survival (PFS) and overall survival (OS) [ECOG PS: Hazard ratio (HR)=2.09; P=0.028 and HR=2.02; P=0.035, respectively; never-smoking: HR=3.53; P=0.007 and HR=1.80; P=0.004, respectively; NLR ≥4.3: HR=4.34; P<0.0001 and HR=4.89; P<0.0001 respectively]. Patients with an NLR <4.3, who had a favorable ECOG PS (0-1) and smoking history in the past, derived the utmost benefit from ICI [n=77; objective response rate (ORR)=35%; PFS and OS: 17.1 and 33.7 months, respectively]. The worst efficacy of ICI was observed in patients who had an NLR ≥4.3 coupled with poor ECOG PS and/or never-smoking status (n=38; ORR=8%; PFS=3.2 months and OS=7.2 months). The remaining patients belonged to the group with intermediate outcomes (n=66; ORR=17%; PFS and OS: 4.3 and 12.2 months, respectively). While combination of these factors was highly predictive for ICIs, it was not associated with outcomes of chemotherapy treatment. Easily available characteristics of the patients allow for highly accurate predictions of outcomes of single-agent ICI therapy in chemotherapy-pretreated NSCLC.

Immunotherapy use in older adults with cancer with frailty: A young SIOG review paper.

Immune checkpoint inhibitors (ICIs) became a treatment option in most tumor types and improved survival in patients with cancer in the last decade. Older patients with cancer are underrepresented in the pivotal clinical trials with ICIs. Older patients with cancer often have significant comorbidities and geriatric syndromes like frailty, which can complicate cancer care and treatment decisions. Frailty is among the most prevalent geriatric syndromes in patients with cancer and could lead to inferior survival and a higher risk of complications in patients treated with chemotherapy. However, the effect of frailty on the efficacy and safety of ICIs is understudied. This review focuses on the available evidence regarding the association between frailty and ICI efficacy and safety. Although the survival benefits of ICIs have generally been shown to be independent of age, the available real-world data has generally suggested higher rates of immune-related adverse events (irAEs) and treatment discontinuation in older patients. While international organizations recommend conducting a comprehensive geriatric assessment CGA to assess and address frailty before the start of anti-cancer therapies, an Eastern Cooperative Oncology Group (ECOG) performance status of 2 or higher is frequently used in clinical practice as synonymous with frailty, albeit with significant limitations. The available data has generally demonstrated diminished ICI efficacy in patients with an ECOG 2 or higher compared to patients with better performance status, while the incidence of high-grade irAEs were similar. Whilst evidence regarding outcomes with ICI in older patients and in those with sub-optimal performance status is growing, there is very limited data specifically evaluating the role of frailty with ICIs. These studies found a shortened overall survival, yet no evidence of a lower response rate to ICIs. These patients experienced more AEs, but they did not necessarily have a higher incidence of irAEs.

The value of performance status in predicting venous thromboembolism in lung cancer patients treated with immune checkpoint inhibitors.

INTRODUCTION: The incidence of venous thromboembolism (VTE) is notably high in lung cancer patients, particularly among those treated with immune checkpoint inhibitors (ICIs). Previous studies have focused on the relationship between Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) and VTE risk in immune checkpoint inhibitor therapy, but available evidence is inconsistent. METHODS: The clinical data of lung cancer patients treated with ICIs were collected and analyzed from West China Hospital between January 2018 and March 2022. ECOG PS score was measured on admission. The primary outcome was the incidence of VTE, encompassing both deep vein thrombosis (DVT) and pulmonary embolism (PE). Multivariate logistic regression analysis was conducted to calculate the odds ratio (OR) and 95% confidence interval (95% CI). RESULTS: A total of 1115 lung cancer patients receiving ICIs were eligible for this study, VTE developed in 105 (9.4%) during the 12-month follow-up, of which 95 (8.5%) had DVT,14 (1.3%) had definite PE. Poor ECOG PS (PS ≥ 2) was associated with an increased risk for VTE (OR = 5.405, 95% CI = 3.067-9.525, P < 0.001), DVT (OR = 4.669, 95% CI = 2.588-8.427, P < 0.001) and PE (OR = 8.413, 95% CI = 2.565-27.600, P < 0.001) after multivariable adjustment in the study cohort. CONCLUSION: VTE occurred in 9.4% of lung cancer patients treated with ICIs, and poor performance status was associated with an increased risk of VTE.

Irregularity of instantaneous gamma frequency in the motor control network characterize visuomotor and proprioceptive information processing.

Objective.The study aims to characterize movements with different sensory goals, by contrasting the neural activity involved in processing proprioceptive and visuo-motor information. To accomplish this, we have developed a new methodology that utilizes the irregularity of the instantaneous gamma frequency parameter for characterization.Approach.In this study, eight essential tremor patients undergoing an awake deep brain stimulation implantation surgery repetitively touched the clinician's finger (forward visually-guided/FV movement) and then one's own chin (backward proprioceptively-guided/BP movement). Neural electrocorticographic recordings from the motor (M1), somatosensory (S1), and posterior parietal cortex (PPC) were obtained and band-pass filtered in the gamma range (30-80 Hz). The irregularity of the inter-event intervals (IEI; inverse of instantaneous gamma frequency) were examined as: (1) auto-information of the IEI time series and (2) correlation between the amplitude and its proceeding IEI. We further explored the network connectivity after segmenting the FV and BP movements by periods of accelerating and decelerating forces, and applying the IEI parameter to transfer entropy methods.Main results.Conceptualizing that the irregularity in IEI reflects active new information processing, we found the highest irregularity in M1 during BP movement, highest in PPC during FV movement, and the lowest during rest at all sites. Also, connectivity was the strongest from S1 to M1 and from S1 to PPC during FV movement with accelerating force and weakest during rest.Significance. We introduce a novel methodology that utilize the instantaneous gamma frequency (i.e. IEI) parameter in characterizing goal-oriented movements with different sensory goals, and demonstrate its use to inform the directional connectivity within the motor cortical network. This method successfully characterizes different movement types, while providing interpretations to the sensory-motor integration processes.

Tumour-infiltrated cortex participates in large-scale cognitive circuits.

The extent to which tumour-infiltrated brain tissue contributes to cognitive function remains unclear. We tested the hypothesis that cortical tissue infiltrated by diffuse gliomas participates in large-scale cognitive circuits using a unique combination of intracranial electrocorticography (ECoG) and resting-state functional magnetic resonance (fMRI) imaging in four patients. We also assessed the relationship between functional connectivity with tumour-infiltrated tissue and long-term cognitive outcomes in a larger, overlapping cohort of 17 patients. We observed significant task-related high gamma (70-250 Hz) power modulations in tumour-infiltrated cortex in response to increased cognitive effort (i.e., switch counting compared to simple counting), implying preserved functionality of neoplastic tissue for complex tasks probing executive function. We found that tumour locations corresponding to task-responsive electrodes exhibited functional connectivity patterns that significantly co-localised with canonical brain networks implicated in executive function. Specifically, we discovered that tumour-infiltrated cortex with larger task-related high gamma power modulations tended to be more functionally connected to the dorsal attention network (DAN). Finally, we demonstrated that tumour-DAN connectivity is evident across a larger cohort of patients with gliomas and that it relates to long-term postsurgical outcomes in goal-directed attention. Overall, this study contributes convergent fMRI-ECoG evidence that tumour-infiltrated cortex participates in large-scale neurocognitive circuits that support executive function in health. These findings underscore the potential clinical utility of mapping large-scale connectivity of tumour-infiltrated tissue in the care of patients with diffuse gliomas.

Click SP/AP Area Ratio Vesrus Tone Burst SP Amplitude to Diagnose Ménière's Disease Using Electrocochleography.

OBJECTIVES: To evaluate the sensitivity and the specificity of summating potential (SP)/action potential (AP) area under the curve (AUC) ratio by a transtympanic electrode and a click stimulus (TT-CS), SP/AP AUC ratio by an extratympanic electrode and a click stimulus (ET-CS) and SP amplitude value by a transtympanic electrode and tone burst stimulus (TT-TBS) in regard of Ménière's disease (MD) diagnosis. This is the first study that compares SP amplitude value performed by a TT-TBS and the SP/AP AUC ratio performed by a TT-CS. STUDY DESIGN: Retrospective comparative study. SETTINGS: Ninety-five patients met the inclusion criteria for electrocochleography (ECochG) testing in a tertiary care center. METHODS: The sensitivity and specificity of our different ECochG protocols were calculated in regard of the diagnosis of MD. RESULTS: The patients' mean age was 54 years old (female predominance). The sensitivity and the specificity of SP/AP area ratio by a TT-CS were 88.5% and 70.0%, respectively. On the other hand, the sensitivity and specificity for the SP amplitude value by a TT-TBS were 60.0% and 55.6%, respectively. SP/AP area ratio by TT-CS was statistically better than SP amplitude value by TT-TBS to detect MD disease (P = .016). However, no difference was identified between SP/AP area ratio by ET-CS and SP amplitude value by a TT-TBS (P = .573). CONCLUSION: SP/AP area ratio by click stimulation has higher sensitivity and specificity to detect MD compared to SP amplitude value by tone burst stimulation. ECochG would be extremely useful in the diagnosis of MD if we use the SP/AP area ratio (sensitivity: 88.5%); therefore, it changes the bad reputation of ECochG sensitivity using SP/AP amplitude ratio (sensitivity: 51.7%) for the diagnosis of MD.