scholarly journals Frontal and parietal alpha oscillations reflect attentional modulation of cross-modal matching

2018 ◽  
Author(s):  
Jonas Misselhorn ◽  
Uwe Friese ◽  
Andreas K. Engel
Keyword(s):  
Gamma Activity ◽  
Multisensory Perception ◽  
Top Down ◽  
Bottom Up ◽  
Alpha Oscillations ◽  
Sensory Inputs ◽  
Gamma Power ◽  
Sensory Cortices ◽  
Underlying Mechanisms ◽  
Selection Of

Multisensory perception is shaped by both attentional selection of relevant sensory inputs and exploitation of stimulus-driven factors that promote cross-modal binding. Underlying mechanisms of both top-down and bottom-up modulations have been linked to changes in alpha/gamma dynamics in primary sensory cortices and temporoparietal cortex. Accordingly, it has been proposed that alpha oscillations provide pulsed inhibition for gamma activity and thereby dynamically route cortical information flow. In this study, we employed a recently introduced multisensory paradigm incorporating both bottom-up and top-down aspects of cross-modal attention in an EEG study. The same trimodal stimuli were presented in two distinct attentional conditions, focused on visual-tactile or audio-visual components, for which cross-modal congruence of amplitude changes had to be evaluated. Neither top-down nor bottom-up cross-modal attention modulated alpha or gamma power in primary sensory cortices. Instead, we found alpha band effects in bilateral frontal and right parietal cortex. We propose that frontal alpha oscillations reflect the origin of top-down control regulating perceptual gains and that modulations of parietal alpha oscillations relates to intersensory re-orienting. Taken together, we suggest that the idea of selective cortical routing via alpha oscillations can be extended from sensory cortices to the frontoparietal attention network.

Sensory regulation of quadrupedal locomotion: a top-down or bottom-up control system?

2012 ◽  
Vol 108 (3) ◽  
pp. 709-711 ◽  
Author(s):  
Yann Thibaudier ◽  
Marie-France Hurteau
Keyword(s):  
Control System ◽  
Central Pattern Generators ◽  
Top Down ◽  
Bottom Up ◽  
Sensory Inputs ◽  
Sensory Regulation ◽  
Before And After ◽  
Pattern Generators

Propriospinal pathways are thought to be critical for quadrupedal coordination by coupling cervical and lumbar central pattern generators (CPGs). However, the mechanisms involved in relaying information between girdles remain largely unexplored. Using an in vitro spinal cord preparation in neonatal rats, Juvin and colleagues ( Juvin et al. 2012 ) have recently shown sensory inputs from the hindlimbs have greater influence on forelimb CPGs than forelimb sensory inputs on hindlimb CPGs, in other words, a bottom-up control system. However, results from decerebrate cats suggest a top-down control system. It may be that both bottom-up and top-down control systems exist and that the dominance of one over the other is task or context dependent. As such, the role of sensory inputs in controlling quadrupedal coordination before and after injury requires further investigation.

scholarly journals Top-down or bottom-up? The selection of shadow rapporteurs in the European Parliament

2020 ◽  
Vol 21 (4) ◽  
pp. 706-727
Author(s):  
Frank M Häge ◽  
Nils Ringe
Keyword(s):  
European Parliament ◽  
Third Party ◽  
Top Down ◽  
Bottom Up ◽  
Principal Agent Theory ◽  
Policy Positions ◽  
Competing Demands ◽  
Group Members ◽  
Selection Of

Shadow rapporteurs play an important role in developing the European Parliament’s collective policy positions and in defending them in inter-institutional negotiations. This study sheds light on the ‘how’ and ‘why’ of shadow rapporteur selection. Qualitative insights from practitioner interviews and a quantitative analysis of shadow rapporteur data from the 7th European Parliament (2009–2014) indicate that the appointment process is primarily one of bottom-up self-selection by group members based on their policy interests. The party group leadership, in the form of group coordinators, plays an important coordinating role when there is competition for a shadow rapporteurship. However, the role of group coordinators is more akin to a third-party arbiter of competing demands than a mechanism of top-down control by the leadership, as suggested by principal-agent theory.

scholarly journals Prioritizing selection of new elements: Bottom-up versus top-down control

2003 ◽  
Vol 65 (8) ◽  
pp. 1231-1242 ◽  
Author(s):  
Mieke Donk ◽  
Jan Theeuwes
Keyword(s):  
Top Down ◽  
Bottom Up ◽  
Selection Of

scholarly journals Attention and Temporal Expectations Modulate Power, Not Phase, of Ongoing Alpha Oscillations

2015 ◽  
Vol 27 (8) ◽  
pp. 1573-1586 ◽  
Author(s):  
Rosanne M. van Diepen ◽  
Michael X Cohen ◽  
Damiaan Denys ◽  
Ali Mazaheri
Keyword(s):  
Phase Angle ◽  
Phase Locking ◽  
Auditory Target ◽  
Alpha Power ◽  
Visual Condition ◽  
Top Down ◽  
Alpha Oscillations ◽  
Alpha Oscillation ◽  
Sensory Cortices ◽  
Phase Angles

The perception of near-threshold visual stimuli has been shown to depend in part on the phase (i.e., time in the cycle) of ongoing alpha (8–13 Hz) oscillations in the visual cortex relative to the onset of that stimulus. However, it is currently unknown whether the phase of the ongoing alpha activity can be manipulated by top–down factors such as attention or expectancy. Using three variants of a cross-modal attention paradigm with constant predictable stimulus onsets, we examined if cues signaling to attend to either the visual or the auditory domain influenced the phase of alpha oscillations in the associated sensory cortices. Importantly, intermixed in all three experiments, we included trials without a target to estimate the phase at target presentation without contamination from the early evoked responses. For these blank trials, at the time of expected target and distractor onset, we examined (1) the degree of the uniformity in phase angles across trials, (2) differences in phase angle uniformity compared with a pretarget baseline, and (3) phase angle differences between visual and auditory target conditions. Across all three experiments, we found that, although the cues induced a modulation in alpha power in occipital electrodes, neither the visual condition nor the auditory cue condition induced any significant phase-locking across trials during expected target or distractor presentation. These results suggest that, although alpha power can be modulated by top–down factors such as attention and expectation, the phase of the ongoing alpha oscillation is not under such control.

scholarly journals Prior expectations induce pre-stimulus sensory templates

2017 ◽  
Author(s):  
Peter Kok ◽  
Pim Mostert ◽  
Floris P. de Lange
Keyword(s):  
Sensory Neurons ◽  
Temporal Resolution ◽  
Representational Content ◽  
Sensory Cortex ◽  
Top Down ◽  
Neural Signals ◽  
Neural Signal ◽  
Bottom Up ◽  
Time Resolved ◽  
Sensory Inputs

AbstractPerception can be described as a process of inference, integrating bottom-up sensory inputs and top-down expectations. However, it is unclear how this process is neurally implemented. It has been proposed that expectations lead to pre-stimulus baseline increases in sensory neurons tuned to the expected stimulus, which in turn affects the processing of subsequent stimuli. Recent fMRI studies have revealed stimulus-specific patterns of activation in sensory cortex as a result of expectation, but this method lacks the temporal resolution necessary to distinguish pre- from post-stimulus processes. Here, we combined human MEG with multivariate decoding techniques to probe the representational content of neural signals in a time-resolved manner. We observed a representation of expected stimuli in the neural signal well before they were presented, demonstrating that expectations indeed induce a pre-activation of stimulus templates. These results suggest a mechanism for how predictive perception can be neurally implemented.

Team coordination and organizational routines: bottoms up – and top down

2016 ◽  
Vol 54 (5) ◽  
pp. 1059-1072 ◽  
Author(s):  
George Christopher Banks ◽  
Jeffrey M. Pollack ◽  
Anson Seers
Keyword(s):  
Point Of View ◽  
Theory And Practice ◽  
Top Down ◽  
Bottom Up ◽  
Team Coordination ◽  
Content Type ◽  
Relational Processes ◽  
Underlying Mechanisms ◽  
Work Coordination ◽  
Explanatory Mechanism

Purpose – Conceptualizations of work coordination historically assumed that work systems are put into place and that these systems shape the ability of workers to accomplish tasks. Formalization has thus long been invoked as an explanatory mechanism for work coordination. Recent studies have extended interest in emergent implicit and relational coordination, yet their underlying mechanisms of bottom-up coordination have yet to be explicated such that formal top-down coordination can be approached as a complementary mechanism rather than an alternative substitute. The purpose of this paper is to integrate the literatures related to coordination and routines, and extend analysis of bottom-up coordination toward an understanding of how it can be complemented by top-down formalized coordination of routines within organizations. Implications of this work, for both theory and practice, are discussed. Design/methodology/approach – A conceptual review was conducted. Findings – By integrating the literatures related to coordination and routines, the authors extend analysis of bottom-up coordination toward an understanding of how it can be complemented by top-down formalized coordination of routines within organizations. Research limitations/implications – From a theory-based point of view, in the present work, the authors integrated the literatures related to coordination and routines and arrived at the conclusion that bottom-up coordination can be complemented by top-down formalized coordination of routines within organizations. Practical implications – The authors suggest that there is a need in the contemporary workplace for implicit, relational processes to enable individuals to continuously assess what changes are needed and adapt coordinated routines to accomplish the task at hand. This propensity will continue to increase as technology facilitates even more seamless communication among employees, organizations, and external partners. Originality/value – For the first time the authors integrate the literatures related to coordination and routines, in order to extend analysis of bottom-up coordination toward an understanding of how it can be complemented by top-down formalized coordination of routines within organizations.

scholarly journals Top-down inhibition of irrelevant information indexed by alpha rhythms is disrupted in migraine

2021 ◽  
Author(s):  
Rémy Masson ◽  
Hesham A ElShafei ◽  
Geneviève Demarquay ◽  
Lesly Fornoni ◽  
Yohana Lévêque ◽  
...  
Keyword(s):  
Cognitive Processing ◽  
Gamma Activity ◽  
Auditory Target ◽  
Alpha Power ◽  
Top Down ◽  
Significant Group ◽  
Bottom Up ◽  
Power Increase ◽  
Visual Areas ◽  
Healthy Participants

There is growing evidence that migraine is associated with attentional abnormalities, both during and outside migraine attacks, which would impact the cognitive processing of sensory stimulation. However, these attention alterations are poorly characterized and their neurophysiological basis is still unclear. Nineteen migraineurs without aura and nineteen healthy participants were recruited to perform a task which used visually-cued auditory targets and distracting sounds to evaluate conjointly top-down and bottom-up attention mechanisms. Magnetoencephalography (MEG) signals were recorded. We investigated anticipatory alpha activity (power increase and decrease) and distractor-induced gamma activity as markers for top-down (inhibition and facilitation) and bottom-up attention, respectively. Compared to healthy participants, migraineurs presented a significantly less prominent alpha power increase in visual areas in anticipation of the auditory target, indexing a reduced inhibition of task-irrelevant visual areas. However, there was no significant group difference regarding the alpha power decrease in the relevant auditory cortices in anticipation of the target, nor regarding the distractor-induced gamma power increase in the ventral attention network. These results in the alpha band suggest that top-down inhibitory processes in the visual cortices are deficient in migraine but there is no clear evidence supporting a disruption of top-down facilitatory attentional processes. This relative inability to suppress irrelevant sensory information may be underlying the self-reported increased distractibility and contribute to sensory disturbances in migraine.

Attention

2017 ◽  
Author(s):  
Martin V. Butz ◽  
Esther F. Kutter
Keyword(s):  
Dynamic Control ◽  
Sensory Information ◽  
Control Process ◽  
Focus Of Attention ◽  
Generative Models ◽  
Top Down ◽  
Bottom Up ◽  
Current Task ◽  
Task Oriented ◽  
Selection Of

Cognition does not work without attention. Attention enables us to focus on particular tasks and particular aspects in the environment. Psychological insights show that attention exhibits bottom-up and top-down components. Attention is attracted from the bottom-up towards unusual, exceptional, and unexpected sensory information. Top-down attention, on the other hand, filters information dependent on the current task-oriented expectations, which depend on the available generative models. This computational interpretation enables the explanation of conjunctive and disjunctive search. Different models of attention emphasize the importance of the unfolding interaction processes and a processing bottleneck can be detected. As a result, attention can be viewed as a dynamic control process that unfolds in redundant, neural fields, in which the selection of one interpretation and thus the processing bottleneck is strongest at the current focus of attention. The actual focus of attention itself is determined by the current behavioral and cognitive goals.

scholarly journals Individual Alpha Frequency Determines the Impact of Bottom-Up Drive on Visual Processing

2021 ◽  
Author(s):  
Stephanie Nelli ◽  
Aayushi Malpani ◽  
Max Boonjindasup ◽  
John T Serences
Keyword(s):  
Visual Processing ◽  
Impact Behavior ◽  
Alpha Band ◽  
Top Down ◽  
Bottom Up ◽  
Alpha Oscillations ◽  
Oscillatory Dynamics ◽  
Alpha Frequency ◽  
Perceptual Performance ◽  
The Impact

Abstract Endogenous alpha oscillations propagate from higher-order to early visual cortical regions, consistent with the observed modulation of these oscillations by top-down factors. However, bottom-up manipulations also influence alpha oscillations, and little is known about how these top-down and bottom-up processes interact to impact behavior. To address this, participants performed a detection task while viewing a stimulus flickering at multiple alpha-band frequencies. Bottom-up drive at a participant’s endogenous alpha frequency either impaired or enhanced perception, depending on the frequency, but not amplitude, of their endogenous alpha oscillation. Fast alpha drive impaired perceptual performance in participants with faster endogenous alpha oscillations, while participants with slower oscillations displaying enhanced performance. This interaction was reflected in slower endogenous oscillatory dynamics in participants with fast alpha oscillations and more rapid dynamics in participants with slow endogenous oscillations when receiving high frequency bottom-up drive. This central tendency may suggest that driving visual circuits at alpha-band frequencies that are away from the peak alpha frequency improves perception through dynamical interactions with the endogenous oscillation. In addition, studies that causally manipulate neural oscillations via exogenous stimulation should carefully consider interacting effects of bottom-up drive and endogenous oscillations on behavior.

scholarly journals Towards an Asian Model of Clusters and Cluster Policy: The Super Cluster Strategy

2020 ◽  
Vol 12 (4) ◽  
pp. 74-90
Author(s):  
Arkadiusz Michał Kowalski
Keyword(s):  
Traditional Approach ◽  
Foreign Direct Investments ◽  
Asian Countries ◽  
Cluster Policy ◽  
Top Down ◽  
Bottom Up ◽  
Cluster Strategy ◽  
Support Mechanisms ◽  
Economic Zones ◽  
Selection Of

Clusters are recognized as important drivers of competitiveness and economic development. There are various models of clusters development all over the world, some of which may be initiated bottom-up by private firms, as in most European countries, or top-down by public administrations. In the case of Asian clusters, many are driven by foreign direct investments (FDI), with the most notable example being China. The objective of this study is to examine the Super Cluster strategy introduced in Thailand in 2015, especially in terms of the rationale and mechanism for selecting assisted clusters as well as the instruments used to support them. The goal is to contribute to a more in-depth formulation of the Asian model of clusters and cluster policy. The conducted analysis shows that Thai strategy deviates from traditional bottom-up approaches to cluster policy, veering towards the top-down approach in which government designates targeted regions and industries for the development of clusters. Another finding is that the Super Cluster strategy shares more common characteristics with Special Economic Zones (SEZ) than it does with the traditional approach to cluster policy in terms of its main objective of attracting foreign direct investments (FDI), securing support mechanisms as well as in the selection of target areas and the type of instruments to be implemented. The experience of Thailand is discussed along with that of other Asian countries, most notably China, in order to identify and verify the characteristics of the Asian model of clusters and cluster policy.

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