Gender effect in human brain responses to bottom-up and top-down attention using the EEG 3D-Vector Field Tomography

2015 ◽  
Author(s):  
Vasiliki E. Kosmidou ◽  
Aikaterini Adam ◽  
Chrysa D. Papadaniil ◽  
Magda Tsolaki ◽  
Leontios J. Hadjileontiadis ◽  
...  
Keyword(s):  
Vector Field ◽  
Human Brain ◽  
Gender Effect ◽  
Top Down ◽  
Bottom Up ◽  
Brain Responses

Dishabituation of Laser-evoked EEG Responses: Dissecting the Effect of Certain and Uncertain Changes in Stimulus Modality

2011 ◽  
Vol 23 (10) ◽  
pp. 2822-2837 ◽  
Author(s):  
Elia Valentini ◽  
Diana M. E. Torta ◽  
André Mouraux ◽  
Gian Domenico Iannetti
Keyword(s):  
Explicit Knowledge ◽  
Sensory Modality ◽  
The Other ◽  
Subjective Perception ◽  
Top Down ◽  
Stimulus Modality ◽  
Bottom Up ◽  
Relative Contribution ◽  
Brain Responses ◽  
Response Habituation

The repetition of nociceptive stimuli of identical modality, intensity, and location at short and constant interstimulus intervals (ISIs) determines a strong habituation of the corresponding EEG responses, without affecting the subjective perception of pain. To understand what determines this response habituation, we (i) examined the effect of introducing a change in the modality of the repeated stimulus, and (ii) dissected the relative contribution of bottom–up, stimulus-driven changes in modality and top–down, cognitive expectations of such a change, on both laser-evoked and auditory-evoked EEG responses. Multichannel EEG was recorded while participants received trains of three stimuli (S1–S2–S3, a triplet) delivered to the hand dorsum at 1-sec ISI. S3 belonged either to the same modality as S1 and S2 or to the other modality. In addition, participants were either explicitly informed or not informed of the modality of S3. We found that introducing a change in stimulus modality produced a significant dishabituation of the laser-evoked N1, N2, and P2 waves; the auditory N1 and P2 waves; and the laser- and auditory-induced event-related synchronization and desynchronization. In contrast, the lack of explicit knowledge of a possible change in the sensory modality of the stimulus (i.e., uncertainty) only increased the ascending portion of the laser-evoked and auditory-evoked P2 wave. Altogether, these results indicate that bottom–up novelty resulting from the change of stimulus modality, and not top–down cognitive expectations, plays a major role in determining the habituation of these brain responses.

scholarly journals Interaction between Bottom-up Saliency and Top-down Control: How Saliency Maps Are Created in the Human Brain

2012 ◽  
Vol 22 (12) ◽  
pp. 2943-2952 ◽  
Author(s):  
Lucia Melloni ◽  
Sara van Leeuwen ◽  
Arjen Alink ◽  
Notger G. Müller
Keyword(s):  
Human Brain ◽  
Top Down ◽  
Bottom Up ◽  
Saliency Maps

Age Effect in Human Brain Responses to Emotion Arousing Images: The EEG 3D-Vector Field Tomography Modeling Approach

2015 ◽  
Vol 7 (3) ◽  
pp. 223-235 ◽  
Author(s):  
Chrysa D. Papadaniil ◽  
Vasiliki E. Kosmidou ◽  
Anthoula C. Tsolaki ◽  
Leontios J. Hadjileontiadis ◽  
Magda Tsolaki ◽  
...  
Keyword(s):  
Vector Field ◽  
Human Brain ◽  
Age Effect ◽  
Modeling Approach ◽  
Brain Responses

scholarly journals Ramsey’s Theory Meets The Human Brain Connectome

2021 ◽  
Author(s):  
Arturo Tozzi
Keyword(s):  
Neural Networks ◽  
Human Brain ◽  
Network Theory ◽  
Neuronal Networks ◽  
Top Down ◽  
Bottom Up ◽  
Functional Interactions ◽  
Brain Connectome

Ramsey’s theory (RAM) from combinatorics and network theory goes looking for regularities and repeated patterns inside structures equipped with nodes and edges. RAM represents the outcome of a dual methodological commitment: by one side a top-down approach evaluates the possible arrangement of specific subgraphs when the number of graph’s vertices is already known, by another side a bottom-up approach calculates the possible number of graph’s vertices when the arrangement of specific subgraphs is already known. Since natural neural networks are often represented in terms of graphs, we suggest to utilize RAM for the analytical and computational assessment of a peculiar structure supplied with neuronal vertices and axonal edges, i.e., the human brain connectome. We discuss how a RAM approach in neuroscientific issues might be able to locate and trace unexplored motifs shared between different cortical and subcortical subareas. Furthermore, we will describe how notable RAM outcomes, such as the Ramsey’s theorem and the Ramsey’s number, could contribute to uncover still unknown anatomical connexions endowed in neuronal networks and unexpected functional interactions among grey zones of the human brain.

scholarly journals Top-down and bottom-up mechanisms in biasing competition in the human brain

2009 ◽  
Vol 49 (10) ◽  
pp. 1154-1165 ◽  
Author(s):  
Diane M. Beck ◽  
Sabine Kastner
Keyword(s):  
Human Brain ◽  
Top Down ◽  
Bottom Up

scholarly journals Sharpening of hierarchical visual feature representations of blurred images

2017 ◽  
Author(s):  
Mohamed Abdelhack ◽  
Yukiyasu Kamitani
Keyword(s):  
Neural Network ◽  
Visual System ◽  
Human Brain ◽  
Deep Neural Network ◽  
Prior Information ◽  
Visual Input ◽  
Top Down ◽  
Bottom Up ◽  
Reference Space ◽  
Blurred Images

AbstractThe robustness of the visual system lies in its ability to perceive degraded images. This is achieved through interacting bottom-up, recurrent, and top-down pathways that process the visual input in concordance with stored prior information. The interaction mechanism by which they integrate visual input and prior information is still enigmatic. We present a new approach using deep neural network (DNN) representation to reveal the effects of such integration on degraded visual inputs. We transformed measured human brain activity resulting from viewing blurred images to the hierarchical representation space derived from a feedforward DNN. Transformed representations were found to veer towards the original non-blurred image and away from the blurred stimulus image. This indicated deblurring or sharpening in the neural representation, and possibly in our perception. We anticipate these results will help unravel the interplay mechanism between bottom-up, recurrent, and top-down pathways, leading to more comprehensive models of vision.Significance statementOne powerful characteristic of the visual system is its ability to complement visual information for incomplete visual images. It operates by projecting information from higher visual and semantic areas of the brain into the lower and mid-level representations of the visual stimulus. We investigate the mechanism by which the human brain represents blurred visual stimuli. By decoding fMRI activity into a feedforward-only deep neural network reference space, we found that neural representations of blurred images are biased towards their corresponding deblurred images. This indicates a sharpening mechanism occurring in the visual cortex.

Psychology and Culture: Top Down Versus Bottom Up?

PsycCRITIQUES ◽  
2005 ◽  
Vol 50 (19) ◽  
Author(s):  
Michael Cole
Keyword(s):  
Top Down ◽  
Bottom Up
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