scholarly journals Neuronal Activity in the Rat Pulvinar Correlates with Multiple Higher-Order Cognitive Functions

Vision ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Fang-Chi Yang ◽  
Rebecca D. Burwell
Keyword(s):  
Neuronal Activity ◽  
Cognitive Functions ◽  
Target Location ◽  
Stimulus Onset ◽  
Visuospatial Attention ◽  
Higher Order ◽  
Top Down ◽  
Bottom Up ◽  
Thalamic Input ◽  
Selection Behavior

The pulvinar, also called the lateral posterior nucleus of the thalamus in rodents, is one of the higher-order thalamic relays and the main visual extrageniculate thalamic nucleus in rodents and primates. Although primate studies report the pulvinar is engaged under attentional demands, there are open questions about the detailed role of the pulvinar in visuospatial attention. The pulvinar provides the primary thalamic input to the posterior parietal cortex (PPC). Both the pulvinar and the PPC are known to be important for visuospatial attention. Our previous work showed that neuronal activity in the PPC correlated with multiple phases of a visuospatial attention (VSA) task, including onset of the visual stimuli, decision-making, task-relevant locations, and behavioral outcomes. Here, we hypothesized that the pulvinar, as the major thalamic input to the PPC, is involved in visuospatial attention as well as in other cognitive functions related to the processing of visual information. We recorded the neuronal activity of the pulvinar in rats during their performance on the VSA task. The task was designed to engage goal-directed, top–down attention as well as stimulus-driven, bottom–up attention. Rats monitored three possible locations for the brief appearance of a target stimulus. An approach to the correct target location was followed by a liquid reward. For analysis, each trial was divided into behavioral epochs demarcated by stimulus onset, selection behavior, and approach to reward. We found that neurons in the pulvinar signaled stimulus onset and selection behavior consistent with the interpretation that the pulvinar is engaged in both bottom–up and top–down visuospatial attention. Our results also suggested that pulvinar cells responded to allocentric and egocentric task-relevant locations.

scholarly journals Trial-by-trial modulation of express visuomotor responses induced by symbolic or barely detectable cues

2021 ◽  
Author(s):  
Samuele Contemori ◽  
Gerald E. Loeb ◽  
Brian D Corneil ◽  
Guy Wallis ◽  
Timothy John Carroll
Keyword(s):  
Superior Colliculus ◽  
Target Location ◽  
Stimulus Presentation ◽  
Surface Emg ◽  
Top Down ◽  
Bottom Up ◽  
Low Contrast ◽  
Visuomotor Transformations ◽  
Shoulder Muscles ◽  
Symbolic Cues

Human cerebral cortex can produce visuomotor responses that are modulated by contextual and task-specific constraints. However, the distributed cortical network for visuomotor transformations limits the minimal response time of that pathway. Notably, humans can generate express visuomotor responses in arm muscles that are inflexibly tuned to the target location and occur 80-120ms from stimulus presentation (stimulus-locked responses, SLRs). This suggests a subcortical pathway for visuomotor transformations that might involve the superior colliculus and its downstream reticulo-spinal projections. Here we investigated whether cognitive expectations can modulate the SLR. In one experiment, we recorded surface EMG from shoulder muscles as participants reached toward a visual target whose location was unpredictable in control conditions, and partially predictable in cue conditions by interpreting a symbolic cue (75% validity). Valid symbolic cues led to earlier and larger SLRs than control conditions; invalid symbolic cues produced later and smaller SLRs than control conditions. This is consistent with a cortical top-down modulation of the putative subcortical SLR-network. In a second experiment, we presented high-contrast targets in isolation (control) or ~24ms after low-contrast stimuli, which could appear at the same (valid cue) or opposite (invalid cue) location as the target, and with equal probability (50% cue validity). We observed earlier SLRs than control with the valid low-contrast cues, whereas the invalid cues led to the opposite results. These findings may reflect bottom-up attentional mechanisms, potentially evolving subcortically via the superior colliculus. Overall, our results support both top-down and bottom-up modulations of the putative subcortical SLR network in humans.

The Origin of Consciousness

2010 ◽  
Vol 18 (3) ◽  
pp. 481-495
Author(s):  
Jonathan Cole
Keyword(s):  
Clinical Medicine ◽  
Neural Correlates ◽  
Higher Order ◽  
Brain Anatomy ◽  
Special Issue ◽  
Top Down ◽  
Bottom Up ◽  
Neural Correlates Of Consciousness ◽  
Definition Of ◽  
External Stimuli

This paper introduces the background to the debate addressed by the papers of this Special Issue of Pragmatics & Cognition. Starting with a definition of consciousness it traces some ways in which the term is applied; from clinical medicine, where it relates somewhat crudely to responsiveness to external stimuli, to more cognitive and philosophical aspects such as higher order consciousness and its content. It then discusses the relation of consciousness to brain anatomy, the neural correlates of consciousness, and its possible evolution. In the meeting which forms the basis for Frith’s core paper, Christof Koch also made important contributions, here précised. A discussion of the origins of consciousness in relation to the top-down and bottom-up models brought to the fore follows suit.

scholarly journals Bottom-Up and Top-Down Paradigms for Psychopathology: A Half-Century Odyssey

2020 ◽  
Vol 16 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Thomas M. Achenbach
Keyword(s):  
Empirical Data ◽  
Higher Order ◽  
Assessment Instruments ◽  
Assessment Data ◽  
Top Down ◽  
Services Research ◽  
Bottom Up ◽  
Conceptual Representations ◽  
And Training ◽  
Internalizing And Externalizing

Bottom-up paradigms prioritize empirical data from which to derive conceptualizations of psychopathology. These paradigms use multivariate statistics to identify syndromes of problems that tend to co-occur plus higher-order groupings such as those designated as internalizing and externalizing. Bottom-up assessment instruments obtain self-ratings and collateral ratings of behavioral, emotional, social, and thought problems and strengths for ages 1½–90+. Ratings of population samples provide norms for syndrome and higher-order scales for each gender, at different ages, rated by different informants, in relation to multicultural norms. The normed assessment instruments operationalize the empirically derived syndromes and higher-order groupings for applications to clinical services, research, and training. Because cross-informant agreement is modest and no single informant provides comprehensive assessment data, software compares ratings by different informants. Top-down paradigms prioritize conceptual representations of the nature and structure of psychopathology, as exemplified by psychodynamic, DSM/ICD, and HiTOP paradigms. Although these paradigms originated with observations, they tend to prioritize conceptual representations over empirical data.

scholarly journals Sub-Optimal Learning of Tactile-Spatial Predictions in Patients with Complex Regional Pain Syndrome

2019 ◽  
Author(s):  
Christopher A. Brown ◽  
Ingrid Scholtes ◽  
Nicholas Shenker ◽  
Michael C. Lee
Keyword(s):  
Complex Regional Pain Syndrome ◽  
Statistical Learning ◽  
Bayesian Model ◽  
Pain Syndrome ◽  
Higher Order ◽  
Spatial Displacement ◽  
Top Down ◽  
Bottom Up ◽  
Spatial Changes ◽  
Statistical Regularities

ABSTRACTIn Complex Regional Pain Syndrome (CRPS), tactile sensory deficits have motivated the therapeutic use of sensory discrimination training. However, the hierarchical organisation of the brain is such that low-level sensory processing can be dynamically influenced by higher-level knowledge, e.g. knowledge learnt from statistical regularities in the environment. It is unknown whether the learning of such statistical regularities is impaired in CRPS. Here, we employed a hierarchical Bayesian model of predictive coding to investigate statistical learning of tactile-spatial predictions in CRPS. Using a sensory change-detection task, we manipulated bottom-up (spatial displacement of a tactile stimulus) and top-down (probabilistic structure of occurrence) factors to estimate hierarchies of prediction and prediction error signals, as well as their respective precisions or reliability. Behavioural responses to spatial changes were influenced by both the magnitude of spatial displacement (bottom-up) and learnt probabilities of change (top-down). The Bayesian model revealed that patients’ predictions (of spatial displacements) were found to be less precise, deviating further from the ideal (statistical optimality) compared to healthy controls. This imprecision was less context-dependent, i.e. more enduring across changes in probabilistic context and less finely-tuned to statistics of the environment. This caused greater precision on prediction errors, resulting in predictions that were driven more by momentary spatial changes and less by the history of spatial changes. These results suggest inefficiencies in higher-order statistical learning in CRPS. This may have implications for therapies based on sensory re-training whose effects may be more short-lived if success depends on higher-order learning.

The Role of Top–Down Focused Spatial Attention in Preattentive Salience Coding and Salience-based Attentional Capture

2016 ◽  
Vol 28 (8) ◽  
pp. 1152-1165 ◽  
Author(s):  
Sabine Bertleff ◽  
Gereon R. Fink ◽  
Ralph Weidner
Keyword(s):  
Spatial Attention ◽  
Attentional Capture ◽  
Target Location ◽  
Search Display ◽  
Attentional Focus ◽  
Control Mechanisms ◽  
Top Down ◽  
Distractor Location ◽  
Bottom Up ◽  
Selective Visual Attention

Selective visual attention requires an efficient coordination between top–down and bottom–up attention control mechanisms. This study investigated the behavioral and neural effects of top–down focused spatial attention on the coding of highly salient distractors and their tendency to capture attention. Combining spatial cueing with an irrelevant distractor paradigm revealed bottom–up based attentional capture only when attention was distributed across the whole search display, including the distractor location. Top–down focusing spatial attention on the target location abolished attentional capture of a salient distractor outside the current attentional focus. Functional data indicated that the missing capture effect was not based on diminished bottom–up salience signals at unattended distractor locations. Irrespectively of whether salient distractors occurred at attended or unattended locations, their presence enhanced BOLD signals at their respective spatial representation in early visual areas as well as in inferior frontal, superior parietal, and medial parietal cortex. Importantly, activity in these regions reflected the presence of a salient distractor rather than attentional capture per se. Moreover, successfully inhibiting attentional capture of a salient distractor at an unattended location further increased neural responses in medial parietal regions known to be involved in controlling spatial attentional shifts. Consequently, data provide evidence that top–down focused spatial attention prevents automatic attentional capture by supporting attentional control processes counteracting a spatial bias toward a salient distractor.

scholarly journals Biology by Design: From Top to Bottom and Back

2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
Brian R. Fritz ◽  
Laura E. Timmerman ◽  
Nichole M. Daringer ◽  
Joshua N. Leonard ◽  
Michael C. Jewett
Keyword(s):  
Synthetic Biology ◽  
Conceptual Model ◽  
Biological Systems ◽  
Higher Order ◽  
Trial And Error ◽  
Top Down ◽  
Bottom Up ◽  
Societal Needs ◽  
Technical Discipline ◽  
Higher Order Networks

Synthetic biology is a nascent technical discipline that seeks to enable the design and construction of novel biological systems to meet pressing societal needs. However, engineering biology still requires much trial and error because we lack effective approaches for connecting basic “parts” into higher-order networks that behave as predicted. Developing strategies for improving the performance and sophistication of our designs is informed by two overarching perspectives: “bottom-up” and “top-down” considerations. Using this framework, we describe a conceptual model for developing novel biological systems that function and interact with existing biological components in a predictable fashion. We discuss this model in the context of three topical areas: biochemical transformations, cellular devices and therapeutics, and approaches that expand the chemistry of life. Ten years after the construction of synthetic biology's first devices, the drive to look beyond what does exist to what can exist is ushering in an era of biology by design.

scholarly journals Polarity-dependent Effects of Biparietal Transcranial Direct Current Stimulation on the Interplay between Target Location and Distractor Saliency in Visual Attention

2018 ◽  
Vol 30 (6) ◽  
pp. 851-866 ◽  
Author(s):  
Magdalena Chechlacz ◽  
Peter C. Hansen ◽  
Joy J. Geng ◽  
Dario Cazzoli
Keyword(s):  
Visual Attention ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Target Location ◽  
Attentional Selection ◽  
Distractor Type ◽  
Top Down ◽  
Bottom Up ◽  
Direct Current Stimulation ◽  
Interhemispheric Competition

Visual attention allows the allocation of limited neural processing resources to stimuli based on their behavioral priorities. The selection of task-relevant visual targets entails the processing of multiple competing stimuli and the suppression of distractors that may be either perceptually salient or perceptually similar to targets. The posterior parietal cortex controls the interaction between top–down (task-driven) and bottom–up (stimulus-driven) processes competing for attentional selection, as well as spatial distribution of attention. Here, we examined whether biparietal transcranial direct current stimulation (tDCS) would modulate the interaction between top–down and bottom–up processes in visual attention. Visual attention function was assessed with a visual discrimination task, in which a lateralized target was presented alone or together with a contralateral, similar or salient, distractor. The accuracy and RTs were measured before and during three stimulation sessions (sham, right anodal/left cathodal, left anodal/right cathodal). The analyses demonstrated (i) polarity-dependent effects of tDCS on the accuracy of target discrimination, but only when the target was presented with a similar distractor; (ii) the tDCS-triggered effects on the accuracy of discriminating targets, accompanied by a similar distractor, varied according to the target location; and (iii) overall detrimental effects of tDCS on RTs were observed, regardless of target location, distractor type, and polarity of the stimulation. We conclude that the observed polarity, distractor type, and target location-dependent effects of biparietal tDCS on the accuracy of target detection resulted from both a modulation of the interaction between top–down and bottom–up attentional processes and the interhemispheric competition mechanisms guiding attentional selection and spatial deployment of attention.

Integrating Interventions after Traumatic Brain Injury: A Synergistic Approach to Neurorehabilitation

2013 ◽  
Vol 14 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Kristen Dams-O'Connor ◽  
Wayne A. Gordon
Keyword(s):  
Emotional Regulation ◽  
Day Treatment ◽  
Life Quality ◽  
Executive Dysfunction ◽  
Higher Order ◽  
Integrative Approach ◽  
Top Down ◽  
Bottom Up ◽  
Psychotherapeutic Interventions ◽  
Synergistic Approach

Deficits in attention, processing speed and executive functioning are among the most commonly reported and functionally limiting cognitive impairments among individuals with TBI. Changes in mood can exacerbate cognitive deficits and reduce life quality. Contemporary hierarchical models of cognitive functioning suggest that attention/arousal processes underlie and support higher-order functions. Building on decades of clinical research, a synergistic, integrative approach to neurorehabilitation is described, which combines bottom-up and top-town cognitive interventions in addition to psychotherapeutic interventions for mood. This approach is intended to address directly impairments in both foundational (i.e., attention) and higher-order (i.e., executive functions) processes. Executive dysfunction is addressed in a top-down fashion through the application of a series of problem-solving and emotional regulation modules that teach and integrate strategies that can be generalised across situations with practice. Attention, arousal and information processing are necessary prerequisites of successful higher-order thinking, attention skills, and are addressed in a bottom-up fashion through intensive individualised attention and processing training tasks. Combining top-down and bottom-up approaches within a comprehensive day-treatment programme can effect a synergistic improvement of overall functioning.

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