2,931 research outputs found

    The Recommendation Architecture: Lessons from Large-Scale Electronic Systems Applied to Cognition

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    A fundamental approach of cognitive science is to understand cognitive systems by separating them into modules. Theoretical reasons are described which force any system which learns to perform a complex combination of real time functions into a modular architecture. Constraints on the way modules divide up functionality are also described. The architecture of such systems, including biological systems, is constrained into a form called the recommendation architecture, with a primary separation between clustering and competition. Clustering is a modular hierarchy which manages the interactions between functions on the basis of detection of functionally ambiguous repetition. Change to previously detected repetitions is limited in order to maintain a meaningful, although partially ambiguous context for all modules which make use of the previously defined repetitions. Competition interprets the repetition conditions detected by clustering as a range of alternative behavioural recommendations, and uses consequence feedback to learn to select the most appropriate recommendation. The requirements imposed by functional complexity result in very specific structures and processes which resemble those of brains. The design of an implemented electronic version of the recommendation architecture is described, and it is demonstrated that the system can heuristically define its own functionality, and learn without disrupting earlier learning. The recommendation architecture is compared with a range of alternative cognitive architectural proposals, and the conclusion reached that it has substantial potential both for understanding brains and for designing systems to perform cognitive functions

    A Functional Architecture Approach to Neural Systems

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    The technology for the design of systems to perform extremely complex combinations of real-time functionality has developed over a long period. This technology is based on the use of a hardware architecture with a physical separation into memory and processing, and a software architecture which divides functionality into a disciplined hierarchy of software components which exchange unambiguous information. This technology experiences difficulty in design of systems to perform parallel processing, and extreme difficulty in design of systems which can heuristically change their own functionality. These limitations derive from the approach to information exchange between functional components. A design approach in which functional components can exchange ambiguous information leads to systems with the recommendation architecture which are less subject to these limitations. Biological brains have been constrained by natural pressures to adopt functional architectures with this different information exchange approach. Neural networks have not made a complete shift to use of ambiguous information, and do not address adequate management of context for ambiguous information exchange between modules. As a result such networks cannot be scaled to complex functionality. Simulations of systems with the recommendation architecture demonstrate the capability to heuristically organize to perform complex functionality

    A physiologically based approach to consciousness

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    The nature of a scientific theory of consciousness is defined by comparison with scientific theories in the physical sciences. The differences between physical, algorithmic and functional complexity are highlighted, and the architecture of a functionally complex electronic system created to relate system operations to device operations is compared with a scientific theory. It is argued that there are two qualitatively different types of functional architecture, and that electronic systems have the instruction architecture based on exchange of unambiguous information between functional components, and biological brains have been constrained by natural selection pressures into the recommendation architecture based on exchange of ambiguous information. The mechanisms by which a recommendation architecture could heuristically define its own functionality are described, and compared with memory in biological brains. Dream sleep is interpreted as the mechanism for minimizing information exchange between functional components in a heuristically defined functional system. The functional role of consciousness of self is discussed, and the route by which the experience of that function described at the psychological level can be related to physiology through a functional architecture is outlined

    A Physiologically Based System Theory of Consciousness

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    A system which uses large numbers of devices to perform a complex functionality is forced to adopt a simple functional architecture by the needs to construct copies of, repair, and modify the system. A simple functional architecture means that functionality is partitioned into relatively equal sized components on many levels of detail down to device level, a mapping exists between the different levels, and exchange of information between components is minimized. In the instruction architecture functionality is partitioned on every level into instructions, which exchange unambiguous system information and therefore output system commands. The von Neumann architecture is a special case of the instruction architecture in which instructions are coded as unambiguous system information. In the recommendation (or pattern extraction) architecture functionality is partitioned on every level into repetition elements, which can freely exchange ambiguous information and therefore output only system action recommendations which must compete for control of system behavior. Partitioning is optimized to the best tradeoff between even partitioning and minimum cost of distributing data. Natural pressures deriving from the need to construct copies under DNA control, recover from errors, failures and damage, and add new functionality derived from random mutations has resulted in biological brains being constrained to adopt the recommendation architecture. The resultant hierarchy of functional separations can be the basis for understanding psychological phenomena in terms of physiology. A theory of consciousness is described based on the recommendation architecture model for biological brains. Consciousness is defined at a high level in terms of sensory independent image sequences including self images with the role of extending the search of records of individual experience for behavioral guidance in complex social situations. Functional components of this definition of consciousness are developed, and it is demonstrated that these components can be translated through subcomponents to descriptions in terms of known and postulated physiological mechanisms

    Entire Sanctification from 1739 to 1900

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    https://place.asburyseminary.edu/firstfruitsheritagematerial/1107/thumbnail.jp

    Secular trends in under-reporting in young people

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    Original article can be found at: http://journals.cambridge.org/action/displayJournal?jid=BJN Copyright The Authors. DOI: 10.1079/BJN20041307National survey data show that reported energy intake has decreased in recent decades despite a rise in the prevalence of obesity. This disparity may be due to a secular increase in under-reporting or a quantitatively greater decrease in energy expenditure. This study examines the extent of under-reporting of energy intake in the National Diet and Nutrition Survey (NDNS) in young people aged 4–18 years in 1997 using published equations to calculate estimated energy requirements. It explores secular changes by comparison with the Diets of British School Children (DBSC) survey in 10–11- and 14–15-year-olds in 1983. In the NDNS, under-reporting (estimated energy requirements – energy intake) represented 21 % of energy needs in girls and 20 % in boys. The magnitude of under-reporting increased significantly with age (P<0·001) and was higher in overweight than lean individuals over 7 years of age. To compare reported energy intake in DBSC and NDNS, the estimated physical activity level from dietary records (dPAL=reported energy intake/predicted BMR) was calculated. If there were no under-reporting, dPAL would represent the subject's true activity level. However, dPAL from the NDNS was significantly lower than that from the DBSC by 8 % and 9 % in boys and girls for those aged 10–11 years, and by 14 % and 11 % for 14–15-year-olds respectively, reaching physiologically implausible levels in the 14–15-year-old girls (dPAL=1·17). If activity levels have remained constant between the two surveys, under-reporting has increased by 8–14 %. The evidence supports a secular trend towards increased under-reporting between the two surveys, but the precise magnitude cannot be quantified in the absence of historical measures of energy expenditure.Peer reviewe

    Diabetic Nephropathy: Perspective on Novel Molecular Mechanisms

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    Diabetes mellitus (DM) is the major cause of end-stage renal disease (ESRD) globally, and novel treatments are urgently needed. Current therapeutic approaches for diabetic nephropathy (DN) are focussing on blood pressure control with inhibitors of the renin-angiotensin-aldosterone system, on glycaemic and lipid control, and life-style changes. In this review, we highlight new molecular insights aiding our understanding of the initiation and progression of DN, including glomerular insulin resistance, dysregulation of cellular substrate utilisation, podocyte-endothelial communication, and inhibition of tubular sodium coupled glucose reabsorption. We believe that these mechanisms offer new therapeutic targets that can be exploited to develop important renoprotective treatments for DN over the next decade

    Human perception of symmetry, raw material and size of Palaeolithic handaxes.

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    It has often been assumed that handaxes were crafted and used primarily by adult males (Hawkes et al. 1997; Kohn & Mithen 1999; Niekus et al. 2012). However, there is no clear scientific or ethnographic evidence to support this. This study aimed to assess modern perceptions of essential morphological traits, including symmetry, raw material and size of handaxes, with a view to ascertaining whether differences exist between males and females in different age groups in their perception of bifaces. A statistical analysis was performed on data gathered through questioning more than 300 individuals, including males and females, adults and subadults (divided into juveniles and children). The study showed that most people prefer symmetrical to asymmetrical handaxes. In particular, females demonstrated a statistically significant preference for symmetrical handaxes. Juveniles and children were significantly more attracted towards symmetrical bifaces than adults, and adult females prefer smaller tools. These results suggest new avenues for research into Palaeolithic tool manufacture and use

    Using the Change Manager Model for the Hippocampal System to Predict Connectivity and Neurophysiological Parameters in the Perirhinal Cortex

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    Theoretical arguments demonstrate that practical considerations, including the needs to limit physiological resources and to learn without interference with prior learning, severely constrain the anatomical architecture of the brain. These arguments identify the hippocampal system as the change manager for the cortex, with the role of selecting the most appropriate locations for cortical receptive field changes at each point in time and driving those changes. This role results in the hippocampal system recording the identities of groups of cortical receptive fields that changed at the same time. These types of records can also be used to reactivate the receptive fields active during individual unique past events, providing mechanisms for episodic memory retrieval. Our theoretical arguments identify the perirhinal cortex as one important focal point both for driving changes and for recording and retrieving episodic memories. The retrieval of episodic memories must not drive unnecessary receptive field changes, and this consideration places strong constraints on neuron properties and connectivity within and between the perirhinal cortex and regular cortex. Hence the model predicts a number of such properties and connectivity. Experimental test of these falsifiable predictions would clarify how change is managed in the cortex and how episodic memories are retrieved
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