scholarly journals Lessons from a broad view of science: a response to Dr Robergs’ article

2018 ◽  
Vol 4 (1) ◽  
pp. e000353
Author(s):  
Flavio Oliveira Pires
Keyword(s):  
A Priori ◽  
Peripheral Fatigue ◽  
Simple Consequence ◽  
Single View ◽  
Scientific Debate ◽  
Central Governor ◽  
Induction Process ◽  
The Central Nervous System ◽  
Online Feedback ◽  
Central Governor Model

Dr Robergs suggested that the central governor model (CGM) is not a well-worded theory, as it deviated from the tenant of falsification criteria. According to his view of science, exercise researches with the intent to prove rather than disprove the theory contribute little to new knowledge and condemn the theory to the label of pseudoscience. However, exercise scientists should be aware of limitations of the falsification criteria. First, the number of potential falsifiers for a given hypothesis is always infinite so that there is no mean to ensure asymmetric comparison between theories. Thus, assuming a competition between CGM and dichotomised central versus peripheral fatigue theories, scientists guided by the falsification principle should know, a priori, all possible falsifiers between these two theories in order to choose the finest one, thereby leading to an oversimplification of the theories. Second, the failure to formulate refutable hypothesis may be a simple consequence of the lack of instruments to make crucial measurements. The use of refutation principles to test the CGM theory requires capable technology for online feedback and feedforward measures integrated in the central nervous system, in a real-time exercise. Consequently, falsification principle is currently impracticable to test CGM theory. The falsification principle must be applied with equilibrium, as we should do with positive induction process, otherwise Popperian philosophy will be incompatible with the actual practice in science. Rather than driving the scientific debate on a biased single view of science, researchers in the field of exercise sciences may benefit more from different views of science.

scholarly journals The inter-comparison of major satellite aerosol retrieval algorithms using simulated intensity and polarization characteristics of reflected light

2010 ◽  
Vol 3 (4) ◽  
pp. 909-932 ◽  
Author(s):  
A. A. Kokhanovsky ◽  
J. L. Deuzé ◽  
D. J. Diner ◽  
O. Dubovik ◽  
F. Ducos ◽  
...  
Keyword(s):  
A Priori ◽  
Light Polarization ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Retrieval Process ◽  
Retrieval Task ◽  
Major Satellite ◽  
Single View ◽  
Intensity Measurements ◽  
Priori Information

Abstract. Remote sensing of aerosol from space is a challenging and typically underdetermined retrieval task, requiring many assumptions to be made with respect to the aerosol and surface models. Therefore, the quality of a priori information plays a central role in any retrieval process (apart from the cloud screening procedure and the forward radiative transfer model, which to be most accurate should include the treatment of light polarization and molecular-aerosol coupling). In this paper the performance of various algorithms with respect to the of spectral aerosol optical thickness determination from optical spaceborne measurements is studied. The algorithms are based on various types of measurements (spectral, angular, polarization, or some combination of these). It is confirmed that multiangular spectropolarimetric measurements provide more powerful constraints compared to spectral intensity measurements alone, particularly those acquired at a single view angle and which rely on a priori assumptions regarding the particle phase function in the retrieval process.

Space Representation in Children

2018 ◽  
pp. 13-22
Keyword(s):  
Object Representation ◽  
Reference Frames ◽  
Cognitive Strategies ◽  
Space Representation ◽  
Spatial Transformations ◽  
Scientific Debate ◽  
Spatial Reference ◽  
Spatial Reference Frames ◽  
The Central Nervous System ◽  
The Individual

With “Spatial Reference Frames” we refer to systems of coordinates by which the central nervous system encodes the relative positions of objects in space, including that of the body itself. A reference system is a way of representing the positions of the subjects / objects in space. The spatial position of an object can be represented in the brain with respect to different classes of reference points, which may be related or not to the position of the subject. In a nutshell, we can say that there are two types of transformations of space imagery: the allocentric spatial transformations, that involve a system of representation from object to object and encode information about the location of an object or its parts in relation to other objects, and egocentric spatial transformations that involve a system of subject-object representation. The human being switches from one code to another, depending on the contingent requirements, giving preference to one or another system according to a set of heterogeneous factors. The gender difference (male / female), for example, plays a key role. Even the individual cognitive strategies make use of different representations in a significantly different way. Manipulation of spatial reference systems constitute a “transnosographic trait” in various neurological and psychiatric disorders. Each of these diseases (autism, schizophrenia, epilepsy, spatial anxiety, Parkinson) reaches some of the structures involved in the manipulation of referential of different spaces. The chapter illustrates Piaget's study on the representation of space in the child and the use of different spatial coding systems, and provides a brief overview of the scientific debate following the Piagetian position.

Neuromuscular fatigue

2017 ◽  
Author(s):  
Sébastien Ratel ◽  
Craig A Williams
Keyword(s):  
Scientific Evidence ◽  
Motor Units ◽  
Voluntary Activation ◽  
Whole Body ◽  
Peripheral Fatigue ◽  
Prepubertal Children ◽  
The Central Nervous System ◽  
Fatiguing Exercise ◽  
Body Dynamic ◽  
Central Factors

Scientific evidence supports the proposition that prepubertal children fatigue less than adults when performing whole-body dynamic activities like maximal cycling, running bouts, and maximal voluntary isometric/isokinetic muscle contractions. Although the mechanisms underpinning differences in fatigue between children and adults are not all fully understood, there is a consensus that children experience less peripheral fatigue (i.e. muscular fatigue) than their older counterparts. Central factors may also account for the lower fatigability in children. Some studies report a higher reduction of muscle voluntary activation during fatiguing exercise in prepubertal children compared to adults. This could reflect a strategy of the central nervous system aimed at limiting the recruitment of motor units, in order to prevent any extensive peripheral fatigue. Further studies are required to clarify this proposition.

scholarly journals Manifold reaching paradigm: how do we handle target redundancy?

2011 ◽  
Vol 106 (4) ◽  
pp. 2086-2102 ◽  
Author(s):  
Bastien Berret ◽  
Enrico Chiovetto ◽  
Francesco Nori ◽  
Thierry Pozzo
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Degrees Of Freedom ◽  
A Priori ◽  
Movement Planning ◽  
Optimal Feedback Control ◽  
Target Redundancy ◽  
The Central Nervous System ◽  
Point To Point ◽  
Muscle Activations

How the central nervous system coordinates the many intrinsic degrees of freedom of the musculoskeletal system is a recurrent question in motor control. Numerous studies addressed it by considering redundant reaching tasks such as point-to-point arm movements, for which many joint trajectories and muscle activations are usually compatible with a single goal. There exists, however, a different, extrinsic kind of redundancy that is target redundancy. Many times, indeed, the final point to reach is neither specified nor unique. In this study, we aim to understand how the central nervous system tackles such an extrinsic redundancy by considering a reaching-to-a-manifold paradigm, more specifically an arm pointing to a long vertical bar. In this case, the endpoint is not defined a priori and, therefore, subjects are free to choose any point on the bar to successfully achieve the task. We investigated the strategies used by subjects to handle this presented choice. Our results indicate both intersubject and intertrial consistency with respect to the freedom provided by the task. However, the subjects' behavior is found to be more variable than during classical point-to-point reaches. Interestingly, the average arm trajectories to the bar and the structure of intertrial endpoint variations could be explained via stochastic optimal control with an energy/smoothness expected cost and signal-dependent motor noise. We conclude that target redundancy is first overcome during movement planning and then exploited during movement execution, in agreement with stochastic optimal feedback control principles, which illustrates how the complementary problems of goal and movement selection may be resolved at once.

scholarly journals Arterial Elasticity, Strength, Fatigue, and Endurance in Older Women

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Gary R. Hunter ◽  
William H. Neumeier ◽  
C. Scott Bickel ◽  
John P. McCarthy ◽  
Gordon Fisher ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Older Women ◽  
Central Fatigue ◽  
Ethnic Origin ◽  
Peripheral Fatigue ◽  
Knee Extensors ◽  
Large Artery ◽  
Arterial Elasticity ◽  
The Central Nervous System

Arterial health may influence muscle function in older adults. Study purpose was to determine whether arterial elasticity is related to strength, central and peripheral fatigue, fatigue at rest, and treadmill endurance. Subjects were 91 healthy women aged >60. Treadmill endurance and maximal oxygen uptake (VO2max) were measured. Peripheral and central fatigue for the knee extensors were evaluated using two isometric fatigue tests (one voluntary and one adding electrical stimulation). Arterial elasticity was determined using radial artery pulse wave analysis. Linear multiple regression was used in statistical analysis. Large artery elasticity was associated with central fatigue(P<0.01)and treadmill endurance(P<0.02)after adjusting for VO2max and knee extension strength. Subjective fatigue at rest was related to large artery elasticity after adjusting for ethnic origin (<0.02). Strength was significantly related to small artery elasticity after adjusting for ethnic origin, leg lean tissue, age, and blood pressure. Arterial elasticity is independently related to strength and fatigue in older women, especially in the central nervous system where arterial elasticity is independently related to perceptions of fatigue at rest and central fatigue. These results suggest that arterial health may be involved with the ability of the central nervous system to activate muscle in older women.

scholarly journals Protein Translation and Psychiatric Disorders

2019 ◽  
Vol 26 (1) ◽  
pp. 21-42 ◽  
Author(s):  
Sophie Laguesse ◽  
Dorit Ron
Keyword(s):  
Psychiatric Disorders ◽  
Cognitive Processes ◽  
Brain Function ◽  
Mrna Translation ◽  
Protein Translation ◽  
Mrna Localization ◽  
Protein Levels ◽  
Central Governor ◽  
The Central Nervous System ◽  
Dendritic Protein Synthesis

Although historically research has focused on transcription as the central governor of protein expression, protein translation is now increasingly being recognized as a major factor for determining protein levels within cells. The central nervous system relies on efficient updating of the protein landscape. Thus, coordinated regulation of mRNA localization, initiation, or termination of translation is essential for proper brain function. In particular, dendritic protein synthesis plays a key role in synaptic plasticity underlying learning and memory as well as cognitive processes. Increasing evidence suggests that impaired mRNA translation is a common feature found in numerous psychiatric disorders. In this review, we describe how malfunction of translation contributes to development of psychiatric diseases, including schizophrenia, major depression, bipolar disorder, and addiction.

Sign in / Sign up

Export Citation Format

Share Document