Electrophysiological connectivity of logical deduction: Early cortical MEG study

Complex human reasoning involves minimal abilities to extract conclusions implied in the available information. These abilities are considered “deductive” because they exemplify certain abstract relations among propositions or probabilities called deductive arguments. However, the electrophysiological dynamics which supports such complex cognitive pro- cesses has not been addressed yet. In this work we consider typically deductive logico- probabilistically valid inferences and aim to verify or refute their electrophysiological functional connectivity differences from invalid inferences with the same content (same relational variables, same stimuli, same relevant and salient features). We recorded the brain electrophysiological activity of 20 participants (age 1⁄4 20.35 ± 3.23) by means of an MEG system during two consecutive reasoning tasks: a search task (invalid condition) without any specific deductive rules to follow, and a logically valid deductive task (valid condition) with explicit deductive rules as instructions. We calculated the functional connectivity (FC) for each condition and conducted a seed-based analysis in a set of cortical regions of interest. Finally, we used a cluster-based permutation test to compare the dif- ferences between logically valid and invalid conditions in terms of FC. As a first novel result we found higher FC for valid condition in beta band between regions of interest and left prefrontal, temporal, parietal, and cingulate structures. FC analysis allows a second novel result which is the definition of a propositional network with operculo-cingular, parietal and medial nodes, specifically including disputed medial deductive “core” areas. The experiment discloses measurable cortical processes which do not depend on content but on truth-functional propositional operators. These experimental novelties may contribute to understand the cortical bases of deductive processes

Source-level EEG and graph theory reveal widespread functional network alterations in focal epilepsy

Objective: The hypersynchronous neuronal activity associated with epilepsy causes widespread functional network disruptions extending beyond the epileptogenic zone. This altered network topology is considered a mediator for non-seizure symptoms, such as cognitive impairment. The aim of this study was to investigate functional network alterations in focal epilepsy patients with good seizure control and high quality of life. Methods: We compared twenty-two focal epilepsy patients and sixteen healthy controls on graph metrics derived from functional connectivity of source-level resting-state EEG. Graph metrics were calculated over a range of network densities in five frequency bands. Results: We observed a significantly increased small world index in patients relative to controls. On the local level, two left-hemisphere regions displayed a shift towards greater alpha band "hubness". The findings were not mediated by age, sex or education, nor by age of epilepsy onset, duration or focus lateralisation. Conclusions: Widespread functional network alterations are evident in focal epilepsy, even in a cohort characterised by successful anti-seizure medication therapy and high quality of life. These findings might support the position that functional network analysis could hold clinical relevance for epilepsy. Significance: Focal epilepsy is accompanied by global and local functional network aberrancies which might be implied in the sustenance of non-seizure symptoms. (c) 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

PENYALAHGUNAAN ASET NEGARA DALAM BENTUK JARINGAN SATELIT UNTUK KEPENTINGAN KORPORASI DIHUBUNGKAN DENGAN UNDANGUNDANG NOMOR 36 TAHUN 1999 TENTANG TELEKOMUNIKASI JO UNDANGUNDANG NOMOR 20 TAHUN 2001 TENTANG TINDAK PIDANA KORUPSI

telekomunikasi sebagaimana dilakukan oleh IM2. IM2 telah menyalahgunakan pita frekuensi 2.1 Ghz, dan secara melawan hukum beroperasi pada jaringan tersebut sehingga menimbulkan kerugian negara. Berdasarkan hal tersebut maka penulis tertarik meneliti, bagaimana Undang-Undang Telekomunikasi jo Peraturan Menteri Komunikasi dan Informatika dan Undang-Undang Tindak Pidana Korupsi mengatur mekanisme pemanfaatan aset negara berupa jaringan satelit, mengapa aset negara berupa jaringan satelit kerap kali disalahgunakan didalam pemanfaatannya oleh korporasi, serta bagaimana upaya yang dapat dilakukan untuk melindungi aset negara dalam bentuk jaringan satelit terhadap penyalahgunaan yang dilakukan oleh korporasi. Penelitian ini menggunakan spesifikasi penelitian yang bersifat deskriftif analitis dengan pendekatan yuridis normatif dibantu yuridis empiris, data yang diperlukan dalam penelitian ini dikumpulkan melalui studi kepustakaan dan studi lapangan, kemudian dianalisis menggunakan teknik analisis data berupa yuridis kualitatif. Pemanfaatan aset negara berupa jaringan satelit melalui pita frekuensi merupakan salah satu hak yang dalam pemanfaatannya diatur oleh peraturan perundang-undangan agar tercipta keadilan, kepastian dan ketertiban, keamanan, keseimbangan, perlindungan dan pemeliharaan dalam pemanfataannya. Jaringan satelit yang merupakan jaringan satelit aset negara pemanfaatannya mensyaratkan izin dan pembayaran tarif tertentu, sehingga konsekuensinya ketika terjadi penyalahgunaan pemanfaatan jaringan satelit, negara akan mengalami kerugian. Aset negara berupa jaringan satelit kerap kali disalahgunakan didalam pemanfaatannya oleh korporasi disebabkan beberapa faktor diantaranya faktor hukum itu sendiri dalam hal ini peraturan perundang-undangannya, faktor penegak hukum, faktor sarana atau fasilitas yang mendukung pengawasan dan penegakan hukum itu sendiri, faktor masyarakat, yakni lingkungan dimana hukum tersebut berlaku atau diterapkan, dalam hal ini yaitu lingkungan korporasi, faktor kebudayaan yakni kurangnya kesadaran hukum korporasi dalam upaya pemanfaatan aset negara secara berkeadilan dan tertib sesuai peraturan perundang-undangan yang berlaku, dimana pemanfaatan yang tidak secara berkeadilan akan membawa negara menuju kepada kehancuran. Upaya yang dapat dilakukan untuk melindungi aset negara dalam bentuk jaringan satelit terhadap penyalahgunaan yang dilakukan oleh korporasi harus berangkat dari beberapa faktor yang menjadi penyebab penyalahgunaan pemanfaatan jaringan satelit diantaranya yaitu melalui upaya preventif berupa revisi perunang-undangan, pengawasan, sosialisasi sert upaya represif berupa penegakan hukum. Penegakan hukum harus dilaksanakan tanpa pandang bulu, sebagai bentuk keyakinan atas doktrin hukum, bahwa setiap orang mempunyai kedudukan yang sama di depan hukum. Kata Kunci: Penyalahgunaan Aset Negara, Jaringan Sateli

Alpha band disruption in the AD-continuum starts in the subjective cognitive decline stage: a MEG study

The consideration of Subjective Cognitive Decline (SCD) as a preclinical stage of AD remains still a matter of debate. Alpha band alterations represent one of the most significant changes in the electrophysiological profile of AD. In particular, AD patients exhibit reduced alpha relative power and frequency. We used alpha band activity measured with MEG to study whether SCD and MCI elders present these electrophysiological changes characteristic of AD, and to determine the evolution of the observed alterations across AD spectrum. The total sample consisted of 131 participants: 39 elders without SCD, 41 elders with SCD and 51 MCI patients. All of them underwent MEG and MRI scans and neuropsychological assessment. SCD and MCI patients exhibited a similar reduction in alpha band activity compared with the no SCD group. However, only MCI patients showed a slowing in their alpha peak frequency compared with both SCD and no SCD. These changes in alpha band were related to worse cognition. Our results suggest that AD-related alterations may start in the SCD stage, with a reduction in alpha relative power. It is later, in the MCI stage, where the slowing of the spectral profile takes place, giving rise to objective deficits in cognitive functioning.This study was supported by two projects from the Spanish Ministry of Economy and Competitiveness, PSI2009-14415-C03-01 and PSI2012-38375-C03-01, a predoctoral fellowship from the Ministry of Economy and Competitiveness to DLS (PSI2012-38375-C03-01), and three predoctoral fellowships from the Ministry of Education to RB,NS,ICRR (FPU13/06009, FPU14/07164, FPU13/02064)

Scopolamine effects on functional brain connectivity : a pharmacological model of Alzheimer's disease

Scopolamine administration may be considered as a psychopharmacological model of Alzheimer's disease (AD). Here, we studied a group of healthy elderly under scopolamine to test whether it elicits similar changes in brain connectivity as those observed in AD, thereby verifying a possible model of AD impairment. We did it by testing healthy elderly subjects in two experimental conditions: glycopyrrolate (placebo) and scopolamine administration. We then analyzed magnetoencephalographic (MEG) data corresponding to both conditions in resting-state with eyes closed. This analysis was performed in source space by combining a nonlinear frequency band-specific measure of functional connectivity (phase locking value, PLV) with network analysis methods. Under scopolamine, functional connectivity between several brain areas was significantly reduced as compared to placebo, in most frequency bands analyzed. Besides, regarding the two complex network indices studied (clustering and shortest path length), clustering significantly decreased in the alpha band while shortest path length significantly increased also in alpha band both after scopolamine administration. Overall our findings indicate that both PLV and graph analysis are suitable tools to measure brain connectivity changes induced by scopolamine, which causes alterations in brain connectivity apparently similar to those reported in AD.Peer reviewe

Four patients with a history of acute exacerbations of COPD: implementing the CHEST/Canadian Thoracic Society guidelines for preventing exacerbations

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Reproducibility of onset and recovery oxygen uptake kinetics in moderately impaired patients with chronic heart failure

Oxygen (O2) kinetics reflect the ability to adapt to or recover from exercise that is indicative of daily life. In patients with chronic heart failure (CHF), parameters of O2 kinetics have shown to be useful for clinical purposes like grading of functional impairment and assessment of prognosis. This study compared the goodness of fit and reproducibility of previously described methods to assess O2 kinetics in these patients. Nineteen CHF patients, New York Heart Association class II–III, performed two constant-load tests on a cycle ergometer at 50% of the maximum workload. Time constants of O2 onset- and recovery kinetics (τ) were calculated by mono-exponential modeling with four different sampling intervals (5 and 10 s, 5 and 8 breaths). The goodness of fit was expressed as the coefficient of determination (R2). Onset kinetics were also evaluated by the mean response time (MRT). Considering O2 onset kinetics, τ showed a significant inverse correlation with peak- \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} \ifmmode\expandafter\dot\else\expandafter\.\fi{V}{\text{O}}_{2} \end{document} (R = −0.88, using 10 s sampling intervals). The limits of agreement of both τ and MRT, however, were not clinically acceptable. O2 recovery kinetics yielded better reproducibility and goodness of fit. Using the most optimal sampling interval (5 breaths), a change of at least 13 s in τ is needed to exceed normal test-to-test variations. In conclusion, O2 recovery kinetics are more reproducible for clinical purposes than O2 onset kinetics in moderately impaired patients with CHF. It should be recognized that this observation cannot be assumed to be generalizable to more severely impaired CHF patients

Remote Effects of Hippocampal Sclerosis on Effective Connectivity during Working Memory Encoding: A Case of Connectional Diaschisis?

Accumulating evidence suggests a role for the medial temporal lobe (MTL) in working memory (WM). However, little is known concerning its functional interactions with other cortical regions in the distributed neural network subserving WM. To reveal these, we availed of subjects with MTL damage and characterized changes in effective connectivity while subjects engaged in WM task. Specifically, we compared dynamic causal models, extracted from magnetoencephalographic recordings during verbal WM encoding, in temporal lobe epilepsy patients (with left hippocampal sclerosis) and controls. Bayesian model comparison indicated that the best model (across subjects) evidenced bilateral, forward, and backward connections, coupling inferior temporal cortex (ITC), inferior frontal cortex (IFC), and MTL. MTL damage weakened backward connections from left MTL to left ITC, a decrease accompanied by strengthening of (bidirectional) connections between IFC and MTL in the contralesional hemisphere. These findings provide novel evidence concerning functional interactions between nodes of this fundamental cognitive network and sheds light on how these interactions are modified as a result of focal damage to MTL. The findings highlight that a reduced (top-down) influence of the MTL on ipsilateral language regions is accompanied by enhanced reciprocal coupling in the undamaged hemisphere providing a first demonstration of “connectional diaschisis.

Remote Effects of Hippocampal Sclerosis on Effective Connectivity during Working Memory Encoding: A Case of Connectional Diaschisis?

Accumulating evidence suggests a role for the medial temporal lobe (MTL) in working memory (WM). However, little is known concerning its functional interactions with other cortical regions in the distributed neural network subserving WM. To reveal these, we availed of subjects with MTL damage and characterized changes in effective connectivity while subjects engaged in WM task. Specifically, we compared dynamic causal models, extracted from magnetoencephalographic recordings during verbal WM encoding, in temporal lobe epilepsy patients (with left hippocampal sclerosis) and controls. Bayesian model comparison indicated that the best model (across subjects) evidenced bilateral, forward, and backward connections, coupling inferior temporal cortex (ITC), inferior frontal cortex (IFC), and MTL. MTL damage weakened backward connections from left MTL to left ITC, a decrease accompanied by strengthening of (bidirectional) connections between IFC and MTL in the contralesional hemisphere. These findings provide novel evidence concerning functional interactions between nodes of this fundamental cognitive network and sheds light on how these interactions are modified as a result of focal damage to MTL. The findings highlight that a reduced (top-down) influence of the MTL on ipsilateral language regions is accompanied by enhanced reciprocal coupling in the undamaged hemisphere providing a first demonstration of “connectional diaschisis.