scholarly journals The Generation and Propagation of the Human Alpha Rhythm

2017 ◽  
Author(s):  
Milan Halgren ◽  
István Ulbert ◽  
Hélène Bastuji ◽  
Dániel Fabó ◽  
Lorand Erőss ◽  
...  
Keyword(s):  
Lower Order ◽  
Short Range ◽  
Alpha Rhythm ◽  
Higher Order ◽  
Cortical Layers ◽  
Top Down ◽  
Posterior Cortex ◽  
Quiet Wakefulness ◽  
Occipital Pole ◽  
Thalamocortical System

AbstractThe alpha rhythm is the longest studied brain oscillation and has been theorized to play a key role in cognition. Still, its physiology is poorly understood. In this study, we used micro and macro electrodes in surgical epilepsy patients to measure the intracortical and thalamic generators of the alpha rhythm during quiet wakefulness. We first found that alpha in posterior cortex propagates from higher-order anterosuperior areas towards the occipital pole, consistent with alpha effecting top-down processing. This cortical alpha leads pulvinar alpha, complicating prevailing theories of a thalamic pacemaker. Finally, alpha is dominated by currents and firing in supragranular cortical layers. Together, these results suggest that the alpharhythm likely reflects short-range supragranular feedback which propagates from higher to lower-order cortex and cortex to thalamus. These physiological insights suggest how alpha could mediate feedback throughout the thalamocortical system.

scholarly journals The generation and propagation of the human alpha rhythm

2019 ◽  
Vol 116 (47) ◽  
pp. 23772-23782 ◽  
Author(s):  
Milan Halgren ◽  
István Ulbert ◽  
Hélène Bastuji ◽  
Dániel Fabó ◽  
Lorand Erőss ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Lower Order ◽  
Short Range ◽  
Alpha Rhythm ◽  
Higher Order ◽  
Cortical Layers ◽  
Posterior Cortex ◽  
Quiet Wakefulness ◽  
Occipital Pole ◽  
Thalamocortical System

The alpha rhythm is the longest-studied brain oscillation and has been theorized to play a key role in cognition. Still, its physiology is poorly understood. In this study, we used microelectrodes and macroelectrodes in surgical epilepsy patients to measure the intracortical and thalamic generators of the alpha rhythm during quiet wakefulness. We first found that alpha in both visual and somatosensory cortex propagates from higher-order to lower-order areas. In posterior cortex, alpha propagates from higher-order anterosuperior areas toward the occipital pole, whereas alpha in somatosensory cortex propagates from associative regions toward primary cortex. Several analyses suggest that this cortical alpha leads pulvinar alpha, complicating prevailing theories of a thalamic pacemaker. Finally, alpha is dominated by currents and firing in supragranular cortical layers. Together, these results suggest that the alpha rhythm likely reflects short-range supragranular feedback, which propagates from higher- to lower-order cortex and cortex to thalamus. These physiological insights suggest how alpha could mediate feedback throughout the thalamocortical system.

scholarly journals Completely top–down hierarchical structure in quantum mechanics

2018 ◽  
Vol 115 (46) ◽  
pp. 11730-11735 ◽  
Author(s):  
Yakir Aharonov ◽  
Eliahu Cohen ◽  
Jeff Tollaksen
Keyword(s):  
Quantum Mechanics ◽  
Lower Order ◽  
Inductive Reasoning ◽  
Main Idea ◽  
Higher Order ◽  
Specific Class ◽  
Strong Correlations ◽  
Many Body ◽  
Top Down ◽  
Quantum Mechanical Systems

Can a large system be fully characterized using its subsystems via inductive reasoning? Is it possible to completely reduce the behavior of a complex system to the behavior of its simplest “atoms”? In this paper we answer these questions in the negative for a specific class of systems and measurements. After a general introduction of the topic, we present the main idea with a simple two-particle example, where strong correlations arise between two apparently empty boxes. This leads to surprising effects within atomic and electromagnetic systems. A general construction based on pre- and postselected ensembles is then suggested, wherein the N-body correlation can be genuinely perceived as a global property, as long as one is limited to performing measurements which we term “strictly local.” We conclude that under certain boundary conditions, higher-order correlations within quantum mechanical systems can determine lower-order ones, but not vice versa. Surprisingly, the lower-order correlations provide no information whatsoever regarding the higher-order correlations. This supports a top–down structure in many-body quantum mechanics.

Neuronal Responses Below Firing Threshold for Subthreshold Cross-Modal Enhancement

2011 ◽  
Vol 23 (4) ◽  
pp. 958-983 ◽  
Author(s):  
Osamu Hoshino
Keyword(s):  
Lower Order ◽  
Direct Interaction ◽  
Active Role ◽  
Higher Order ◽  
Perceptual Awareness ◽  
Top Down ◽  
Population Response ◽  
Somatosensory Stimulation ◽  
Firing Threshold ◽  
Reaction Speed

Multisensory integration (such as somatosensation-vision, gustation-olfaction) could occur even between subthreshold stimuli that in isolation do not reach perceptual awareness. For example, when a somatosensory (subthreshold) stimulus is delivered within a close spatiotemporal congruency, a visual (subthreshold) stimulus evokes a visual percept. Cross-modal enhancement of visual perception is maximal when the somatosensory stimulation precedes the visual one by tens of milliseconds. This rapid modulatory response would not be consistent with a top-down mechanism acting through higher-order multimodal cortical areas, but rather a direct interaction between lower-order unimodal areas. To elucidate the neuronal mechanisms of subthreshold cross-modal enhancement, we simulated a neural network model. In the model, lower unimodal (X, Y) and higher multimodal (M) networks are reciprocally connected by bottom-up and top-down axonal projections. The lower networks are laterally connected with each other. A pair of stimuli was presented to the lower networks, whose respective intensities were too weak to induce salient neuronal activity (population response) when presented alone. Neurons of the Y network were slightly depolarized below firing threshold when a cross-modal stimulus was presented alone to the X network. This allowed the Y network to make a rapid (within tens of milliseconds) population response when presented with a subsequent congruent stimulus. The reaction speed of the Y network was accelerated, provided that the top-down projections were strengthened. We suggest that a subthreshold (nonpopulation) response to a cross-modal stimulus, acting through interaction between lower (primary unisensory) areas, may be essential for a rapid suprathreshold (population) response to a congruent stimulus that follows. Top-down influences on cross-modal enhancement may be faster than expected, accelerating reaction speed to input, in which ongoing-spontaneous subthreshold excitation of lower-order unimodal cells by higher-order multimodal cells may play an active role.

The Effect of Activated Higher-order Goals on Emotional Responses in Lower-order Activities

2003 ◽  
Author(s):  
Sunyoung Oh ◽  
Daniel Cervone ◽  
Taeho Ham ◽  
June Yum
Keyword(s):  
Lower Order ◽  
Emotional Responses ◽  
Higher Order

READING EXERCISES FOR VIII GRADE STUDENTS BASED ON BLOOM’S TAXONOMY

2017 ◽  
Vol 6 (3) ◽  
Author(s):  
Intan Permata Sari And Indra Hartoyo
Keyword(s):  
Data Analysis ◽  
Lower Order ◽  
Bloom's Taxonomy ◽  
Higher Order Thinking ◽  
Thinking Skills ◽  
Higher Order ◽  
Critical Thinking Skills ◽  
Thinking Skill ◽  
Level Of Education ◽  
Bloom’S Taxonomy

This study is aimed at (1) analyzing reading exercises based Bloom’s taxonomy for VIII grade in English on Sky textbook. (2) Found the distribution of the lower and higher order thinking skill in reading exercises. (3) To reason for level reading exercises. After analyzed the data, the result of the data analysis also infers that the six levels of Bloom’s taxonomy in reading exercises weren’t applied totally. The creating skill doesn’t have distribution in reading exercise, and the understanding – remembering level more dominant than another levels. The distribution of the higher order thinking level was lower than the lower order thinking level and the six levels are not appropriate with the proportion for each level of education based Bloom’s taxonomy, such as the distribution of the creating level in the reading exercise must be a concern because no question that belong to the creating level. It was concluded that reading exercises in English on Sky textbook cannot improve students' critical thinking skills for VIII grade.

Factors associated with complications in higher order compared to lower order repeat

2016 ◽  
Vol 1 (1) ◽  
pp. 32-39
Author(s):  
Tahira Akhtar ◽  
◽  
Aahsann Kazemi ◽  
Keyword(s):  
Lower Order ◽  
Higher Order ◽  
Factors Associated

Internal categoricity and truth

2018 ◽  
Author(s):  
Tim Button ◽  
Sean Walsh
Keyword(s):  
Model Theory ◽  
Lower Order ◽  
Higher Order ◽  
Mathematical Truth ◽  
Object Language ◽  
Famous Result ◽  
Famous Paper ◽  
Truth Value ◽  
Truth Operator

This chapter considers whether internal categoricity can be used to leverage any claims about mathematical truth. We begin by noting that internal categoricity allows us to introduce a truth-operator which gives an object-language expression to the supervaluationist semantics. In this way, the univocity discussed in previous chapters might seem to secure an object-language expression of determinacy of truth-value; but this hope falls short, because such truth-operators must be carefully distinguished from truth-predicates. To introduce these truth-predicates, we outline an internalist attitude towards model theory itself. We then use this to illuminate the cryptic conclusions of Putnam's justly-famous paper ‘Models and Reality’. We close this chapter by presenting Tarski’s famous result that truth for lower-order languages can be defined in higher-order languages.

scholarly journals Alzheimer’s Disease Progressively Reduces Visual Functional Network Connectivity

2021 ◽  
pp. 1-14
Author(s):  
Jie Huang ◽  
Paul Beach ◽  
Andrea Bozoki ◽  
David C. Zhu
Keyword(s):  
Visual Cortex ◽  
Lower Order ◽  
Resting State ◽  
Visual Processing ◽  
Network Connectivity ◽  
Higher Order ◽  
Functional Network ◽  
Functional Networks ◽  
The Face ◽  
Processing Network

Background: Postmortem studies of brains with Alzheimer’s disease (AD) not only find amyloid-beta (Aβ) and neurofibrillary tangles (NFT) in the visual cortex, but also reveal temporally sequential changes in AD pathology from higher-order association areas to lower-order areas and then primary visual area (V1) with disease progression. Objective: This study investigated the effect of AD severity on visual functional network. Methods: Eight severe AD (SAD) patients, 11 mild/moderate AD (MAD), and 26 healthy senior (HS) controls undertook a resting-state fMRI (rs-fMRI) and a task fMRI of viewing face photos. A resting-state visual functional connectivity (FC) network and a face-evoked visual-processing network were identified for each group. Results: For the HS, the identified group-mean face-evoked visual-processing network in the ventral pathway started from V1 and ended within the fusiform gyrus. In contrast, the resting-state visual FC network was mainly confined within the visual cortex. AD disrupted these two functional networks in a similar severity dependent manner: the more severe the cognitive impairment, the greater reduction in network connectivity. For the face-evoked visual-processing network, MAD disrupted and reduced activation mainly in the higher-order visual association areas, with SAD further disrupting and reducing activation in the lower-order areas. Conclusion: These findings provide a functional corollary to the canonical view of the temporally sequential advancement of AD pathology through visual cortical areas. The association of the disruption of functional networks, especially the face-evoked visual-processing network, with AD severity suggests a potential predictor or biomarker of AD progression.

scholarly journals Examining Bloom’s Taxonomy in Multiple Choice Questions: Students’ Approach to Questions

2021 ◽  
Author(s):  
J. K. Stringer ◽  
Sally A. Santen ◽  
Eun Lee ◽  
Meagan Rawls ◽  
Jean Bailey ◽  
...  
Keyword(s):  
Lower Order ◽  
Multiple Choice ◽  
Bloom's Taxonomy ◽  
Thinking Skills ◽  
Higher Order ◽  
Multiple Choice Questions ◽  
Analytic Thinking ◽  
Bloom’S Taxonomy ◽  
Degree Of Confidence ◽  
Clinical Reasoning Skills

Abstract Background Analytic thinking skills are important to the development of physicians. Therefore, educators and licensing boards utilize multiple-choice questions (MCQs) to assess these knowledge and skills. MCQs are written under two assumptions: that they can be written as higher or lower order according to Bloom’s taxonomy, and students will perceive questions to be the same taxonomical level as intended. This study seeks to understand the students’ approach to questions by analyzing differences in students’ perception of the Bloom’s level of MCQs in relation to their knowledge and confidence. Methods A total of 137 students responded to practice endocrine MCQs. Participants indicated the answer to the question, their interpretation of it as higher or lower order, and the degree of confidence in their response to the question. Results Although there was no significant association between students’ average performance on the content and their question classification (higher or lower), individual students who were less confident in their answer were more than five times as likely (OR = 5.49) to identify a question as higher order than their more confident peers. Students who responded incorrectly to the MCQ were 4 times as likely to identify a question as higher order than their peers who responded correctly. Conclusions The results suggest that higher performing, more confident students rely on identifying patterns (even if the question was intended to be higher order). In contrast, less confident students engage in higher-order, analytic thinking even if the question is intended to be lower order. Better understanding of the processes through which students interpret MCQs will help us to better understand the development of clinical reasoning skills.

REACTION OF ALDOSES AND KETOSES WITH LEAD TETRAACETATE

1956 ◽  
Vol 34 (4) ◽  
pp. 541-553 ◽  
Author(s):  
A. S. Perlin ◽  
Carol Brice
Keyword(s):  
Lower Order ◽  
Higher Order ◽  
Lead Tetraacetate ◽  
Pyranose Form ◽  
Reaction Proceeds ◽  
Furanose Form ◽  
Rare Sugars

Lead tetraacetate is highly selective for oxidation of α-hydroxy-hemiacetal groups and hence most readily attacks cyclic forms of the sugars. The reaction proceeds stepwise; the hemiacetal α-glycol being cleaved and the monoester of a correspondingly shorter-chained sugar formed. After cyclization the new sugar in turn is oxidized at the hemiacetal α-glycol group to yield a diester of a still-lower-order member of the series. In this manner D-glucose first yields mono-O-formyl-D-arabinose and then di-O-formyl-D-erythrose. Similarly, D-fructose is degraded to a glycolate ester of D-erythrose and finally to a formate–glycolate diester of D-glyceraldehyde. Some relatively rare sugars thus may conveniently be prepared directly from abundant higher-order members of the series. The reactions appear to involve preferential attack of the furanose form of a sugar rather than of the normally-predominant pyranose form, or possibly migration of ester groups towards the reducing end of the sugars.

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