Active inference as a computational framework for consciousness

Recently, the mechanistic framework of active inference has been put forward as a principled foundation to develop an overarching theory of consciousness which would help address conceptual disparities in the field (Wiese 2018; Hohwy and Seth 2020). For that promise to bear out, we argue that current proposals resting on the active inference scheme need refinement to become a process theory of consciousness. One way of improving a theory in mechanistic terms is to use formalisms such as computational models that implement, attune and validate the conceptual notions put forward. Here, we examine how computational modelling approaches have been used to refine the theoretical proposals linking active inference and consciousness, with a focus on the extent and success to which they have been developed to accommodate different facets of consciousness and experimental paradigms, as well as how simulations and empirical data have been used to test and improve these computational models. While current attempts using this approach have shown promising results, we argue they remain preliminary in nature. To refine their predictive and structural validity, testing those models against empirical data is needed i.e., new and unobserved neural data. A remaining challenge for active inference to become a theory of consciousness is to generalize the model to accommodate the broad range of consciousness explananda; and in particular to account for the phenomenological aspects of experience. Notwithstanding these gaps, this approach has proven to be a valuable avenue for theory advancement and holds great potential for future research

Participative ergonomics for the improvement of occupational health and safety in industry: a focus group-based approach

This paper introduces a participative approach to the investigation and promotion of health and safety in industry. The proposed methodology promotes the active participation of the workers in the analysis of consequences and causes of unsafe behaviours that may result in work-related musculoskeletal disorders, accidents, injuries or near-misses. The developed participative technique is the Focus Group with Workers, based on the Fault Tree Analysis method (FGW-FTA). Focus groups are conventionally used by social and behavioural researchers to understand opinions, motivations, attitudes, and mental processes that underlie people behaviours. The innovative procedure in this paper addresses researchers and safety professionals during the focus groups with the workers for the identification of critical risk factors in the workplace. The result is a structured analysis, operated by and with the workers, for the identification of consequences and causes of unsafe behaviours. Finally, the developed methodology addresses the definition of a set of preventive and protective measures, and corrective actions for the improvement of health and safety in the workplace. An experimental study in an Italian boiler manufacturer describes the proposed methodology and the results of the focus groups with the workers. An evaluation questionnaire was elaborated to investigate the workers’ knowledge on occupational health and safety. A second questionnaire was developed to understand the workers’ perception on occupational risks. Each participant was invited to fill in both the questionnaires before and after the focus groups with the workers. The results of the study proved the effectiveness of the developed methodology in improving workers knowledge and perceptions on occupational health and safety

The influence of auditory attention on rhythmic speech tracking: Implications for studies of unresponsive patients

Language comprehension relies on integrating words into progressively more complex structures, like phrases and sentences. This hierarchical structure-building is reflected in rhythmic neural activity across multiple timescales in E/MEG in healthy, awake participants. However, recent studies have shown evidence for this “cortical tracking” of higher-level linguistic structures also in a proportion of unresponsive patients. What does this tell us about these patients’ residual levels of cognition and consciousness? Must the listener direct their attention toward higher level speech structures to exhibit cortical tracking, and would selective attention across levels of the hierarchy influence the expression of these rhythms? We investigated these questions in an EEG study of 72 healthy human volunteers listening to streams of monosyllabic isochronous English words that were either unrelated (scrambled condition) or composed of four-word-sequences building meaningful sentences (sentential condition). Importantly, there were no physical cues between four-word-sentences. Rather, boundaries were marked by syntactic structure and thematic role assignment. Participants were divided into three attention groups: from passive listening (passive group) to attending to individual words (word group) or sentences (sentence group). The passive and word groups were initially naïve to the sentential stimulus structure, while the sentence group was not. We found significant tracking at word- and sentence rate across all three groups, with sentence tracking linked to left middle temporal gyrus and right superior temporal gyrus. Goal-directed attention to words did not enhance word-rate-tracking, suggesting that word tracking here reflects largely automatic mechanisms, as was shown for tracking at the syllable-rate before. Importantly, goal-directed attention to sentences relative to words significantly increased sentence-rate-tracking over left inferior frontal gyrus. This attentional modulation of rhythmic EEG activity at the sentential rate highlights the role of attention in integrating individual words into complex linguistic structures. Nevertheless, given the presence of high-level cortical tracking under conditions of lower attentional effort, our findings underline the suitability of the paradigm in its clinical application in patients after brain injury. The neural dissociation between passive tracking of sentences and directed attention to sentences provides a potential means to further characterise the cognitive state of each unresponsive patient

Phosphorylation of rat brain calpastatins by protein kinase C

AbstractCalpastatin, the natural inhibitor of calpain, is present in rat brain in multiple forms, having different molecular masses, due to the presence of one (low Mr form) or four (high Mr form) repetitive inhibitory domains. Recombinant and native calpastatin forms are substrates of protein kinase C, which phosphorylates a single serine residue at their N-terminus. Furthermore, both low and high Mr calpastatins are phosphorylated by protein kinase C at the same site. These calpastatin forms are phosphorylated also by protein kinase A, although with a lower efficiency. The incorporation of a phosphate group determines an increase in the concentration of Ca2+ required to induce the formation of the calpain-calpastatin complex. This effect results in a large decrease of the inhibitory efficiency of calpastatins. We suggest that phosphorylation of calpastatin represents a mechanism capable to balance the actual amount of active calpastatin to the level of calpain to be activated

Travelling-wave resonant four-wave mixing breaks the limits of cavity-enhanced all-optical wavelength conversion

Wave mixing inside optical resonators, while experiencing a large enhancement of the nonlinear interaction efficiency, suffers from strong bandwidth constraints, preventing its practical exploitation for processing broad-band signals. Here we show that such limits are overcome by the new concept of travelling-wave resonant four-wave mixing (FWM). This approach combines the efficiency enhancement provided by resonant propagation with a wide-band conversion process. Compared with conventional FWM in bare waveguides, it exhibits higher robustness against chromatic dispersion and propagation loss, while preserving transparency to modulation formats. Travelling-wave resonant FWM has been demonstrated in silicon-coupled ring resonators and was exploited to realize a 630-μm-long wavelength converter operating over a wavelength range wider than 60 nm and with 28-dB gain with respect to a bare waveguide of the same physical length. Full compatibility of the travelling-wave resonant FWM with optical signal processing applications has been demonstrated through signal retiming and reshaping at 10 Gb s−

A scoping review on the approaches for cannulation of reno-visceral target vessels during complex endovascular aortic repair

OBJECTIVES: The aim of this study was to assess the approaches to reno-visceral target vessels (TVs) cannulation during branched-fenestrated endovascular aortic repair, determine the evidence base that links these approaches to clinical outcomes and identify literature gaps. METHODS: A scoping review following the PRISMA Protocols Extension for Scoping Reviews was performed. Available full-text studies published in English (PubMed, Cochrane and EMBASE databases; last queried, 31 June 2022) were systematically reviewed and analysed. Data were reported as descriptive narrative or tables, without any statistical analysis nor quality assessment. RESULTS: Fourteen retrospective articles were included. Seven articles studied the use of upper extremity access (UEA) during branched-fenestrated endovascular aortic repair, 3 studied the use of steerable sheaths and 4 included both approaches. A left UEA was used in 757 patients (technical success: 99%, stroke rate: 1-3%) and a right UEA in 215 patients (technical success: 92-98%, stroke rate: 0-13%). Seven studies (1066 patients) described a surgical access only (technical success: 80-99%, stroke rate: 0-13%), while 3 studies (146 patients) described a percutaneous access only (technical success: 83-90%, stroke rate: 3%) and lastly 4 studies compared UEA versus use of steerable sheaths from the transfemoral approach (TFA) (UEA: 563 patients, technical success: 95-98%, stroke rate: 1-8%; TFA: 209 patients, technical success: 98-100%, stroke rate: 0-1%). CONCLUSIONS: Both UEA and TFA as cannulation approaches were associated with high technical success and low perioperative complications. Currently, there is a paucity of high-quality data to provide definitive indication. Optimal UEA in terms of side (left versus right) and approach (surgical versus percutaneous) needs further study

A stochastic simulation approach for production scheduling and investment planning in the tile industry

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INSPEcT: a computational tool to infer mRNA synthesis, processing and degradation dynamics from RNA- and 4sU-seq time course experiments.

Abstract Motivation: Cellular mRNA levels originate from the combined action of multiple regulatory processes, which can be recapitulated by the rates of pre-mRNA synthesis, pre-mRNA processing and mRNA degradation. Recent experimental and computational advances set the basis to study these intertwined levels of regulation. Nevertheless, software for the comprehensive quantification of RNA dynamics is still lacking. Results: INSPEcT is an R package for the integrative analysis of RNA- and 4sU-seq data to study the dynamics of transcriptional regulation. INSPEcT provides gene-level quantification of these rates, and a modeling framework to identify which of these regulatory processes are most likely to explain the observed mRNA and pre-mRNA concentrations. Software performance is tested on a synthetic dataset, instrumental to guide the choice of the modeling parameters and the experimental design. Availability and implementation: INSPEcT is submitted to Bioconductor and is currently available as Supplementary Additional File S1. Contact: [email protected] Supplementary Information: Supplementary data are available at Bioinformatics online

Fenestrated-branched endovascular repair for distal thoracoabdominal aortic pathology after total aortic arch replacement with frozen elephant trunk

Objective: To report the outcomes of fenestrated-branched endovascular repair (FBEVAR) for thoracoabdominal aortic pathology after total aortic arch replacement with frozen elephant trunk (TAR+FET). Methods: Interrogation of prospectively maintained databases from four high-volume aortic centers identified consecutive patients treated with distal FBEVAR after prior TAR+FET between August 2013 and September 2020. The primary end point was 30-day/in-hospital mortality. Secondary end points were technical success, early clinical success, midterm survival, and freedom from reintervention. Data are presented as median (interquartile range). Results: A total of 39 patients (21 men; median age, 73 years [67-75 years]) with degenerative (n = 22) and postdissection thoracoabdominal aortic aneurysms (n = 17) (median diameter, 71 mm [61-78 mm]) were identified. Distal FBEVAR was intended in 27 patients (median interval, 9.8 months [6.2-16.6 months]), anticipated in 7, and unexpected in 5. A total of 31 patients had a two- (n = 24) or three-stage (n = 7) distal FBEVAR. Renovisceral target vessel preservation was 99.3% (145 of 146). Early primary and secondary technical success was 92% and 97%, respectively. Thirty-day mortality was 2.6% (n = 1; respiratory failure and spinal cord ischemia [SCI]). Six survivors also developed SCI, which was associated with complete (n = 4) or partial recovery (n = 2) at hospital discharge. No patients required renal replacement therapy or suffered a stroke. Early clinical success was 95%. Median follow-up was 30.5 months (23.7-49.7 months). Eleven patients required 16 late reinterventions. Estimated 3-year survival and freedom from reintervention were 84% ± 6% and 63% ± 10%, respectively. Conclusions: Distal FBEVAR after prior TAR+FET is associated with high technical success and low early mortality. The risk of SCI is significant although the majority of patients demonstrate full or partial recovery before hospital discharge. Midterm patient survival is favorable, but there remains a high requirement for late reintervention. FBEVAR represents an acceptable alternative to distal open thoracoabdominal aortic aneurysm repair