scholarly journals Global integration of local color differences in transparency perception: An fMRI study

2006 ◽  
Vol 23 (3-4) ◽  
pp. 357-364 ◽  
Author(s):  
MICHEL DOJAT ◽  
LOŸS PIETTRE ◽  
CHANTAL DELON-MARTIN ◽  
MATHILDE PACHOT-CLOUARD ◽  
CHRISTOPH SEGEBARTH ◽  
...  
Keyword(s):  
Anterior Part ◽  
Cortical Activation ◽  
Parahippocampal Gyrus ◽  
Global Integration ◽  
Local Color ◽  
Perceptual Integration ◽  
Geometric Patterns ◽  
Fmri Study ◽  
Color Differences ◽  
Cortical Regions

In normal viewing, the visual system effortlessly assigns approximately constant attributes of color and shape to perceived objects. A fundamental component of this process is the compensation for illuminant variations and intervening media to recover reflectance properties of natural surfaces. We exploited the phenomenon of transparency perception to explore the cortical regions implicated in such processes, using fMRI. By manipulating the coherence of local color differences around a region in an image, we interfered with their global perceptual integration and thereby modified whether the region appeared transparent or not. We found the major cortical activation due to global integration of local color differences to be in the anterior part of the parahippocampal gyrus. Regions differentially activated by chromatic versus achromatic geometric patterns showed no significant differential response related to the coherence/incoherence of local color differences. The results link the integration of local color differences in the extraction of a transparent layer with sites activated by object-related properties of an image.

IC-P3-204: Effects of donepezil on cortical activation in MCI: A placebo controlled fMRI study

2008 ◽  
Vol 4 ◽  
pp. T88-T88
Author(s):  
Jeffrey R. Petrella ◽  
Steven E. Prince ◽  
Sriyesh Krishnan ◽  
Hala Husain ◽  
Lisa Kelly ◽  
...  
Keyword(s):  
Cortical Activation ◽  
Fmri Study

scholarly journals The Effects of 10 Hz and 20 Hz tACS in Network Integration and Segregation in Chronic Stroke: A Graph Theoretical fMRI Study

2021 ◽  
Vol 11 (3) ◽  
pp. 377
Author(s):  
Cheng Chen ◽  
Kai Yuan ◽  
Winnie Chiu-wing Chu ◽  
Raymond Kai-yu Tong
Keyword(s):  
Chronic Stroke ◽  
Global Integration ◽  
Neural Responses ◽  
Whole Brain ◽  
Brain Level ◽  
Fmri Study ◽  
Transcranial Alternating Current Stimulation ◽  
Specific Stimulation ◽  
Clinical Potential ◽  
Local Segregation

Transcranial alternating current stimulation (tACS) has emerged as a promising technique to non-invasively modulate the endogenous oscillations in the human brain. Despite its clinical potential to be applied in routine rehabilitation therapies, the underlying modulation mechanism has not been thoroughly understood, especially for patients with neurological disorders, including stroke. In this study, we aimed to investigate the frequency-specific stimulation effect of tACS in chronic stroke. Thirteen chronic stroke patients underwent tACS intervention, while resting-state functional magnetic resonance imaging (fMRI) data were collected under various frequencies (sham, 10 Hz and 20 Hz). The graph theoretical analysis indicated that 20 Hz tACS might facilitate local segregation in motor-related regions and global integration at the whole-brain level. However, 10 Hz was only observed to increase the segregation from whole-brain level. Additionally, it is also observed that, for the network in motor-related regions, the nodal clustering characteristic was decreased after 10 Hz tACS, but increased after 20 Hz tACS. Taken together, our results suggested that tACS in various frequencies might induce heterogeneous modulation effects in lesioned brains. Specifically, 20 Hz tACS might induce more modulation effects, especially in motor-related regions, and they have the potential to be applied in rehabilitation therapies to facilitate neuromodulation. Our findings might shed light on the mechanism of neural responses to tACS and facilitate effectively designing stimulation protocols with tACS in stroke in the future.

scholarly journals Neurolinguistics

2007 ◽  
Vol 40 (1) ◽  
pp. 86-88
Keyword(s):  
Los Angeles ◽  
Brain Research ◽  
Event Related Potential ◽  
Cortical Activation ◽  
Fmri Study ◽  
Neuroimaging Data ◽  
Interlingual Homographs ◽  
L1 And L2 ◽  
Phonological Complexity ◽  
Cortical Activation Pattern

07–165Crinion, J., R. Turner, A. Grogan, T. Hanakawa, U. Noppeney, J. T. Devlin, T. Aso, S. Urayama, H. Fukuyama, K. Stockton, K. Usui, D. W. Green & C. J. Price (U College, London, UK; [email protected]), Language control in the bilingual brain. Science (American Association for the Advancement of Science) 312.5779 (2006), 1537–1540.07–166Desai, Rutvik (U Trier, Germany), Lisa L. Conant, Eric Waldron & Jeffrey R. Binder, fMRI of past tense processing: The effects of phonological complexity and task difficulty. Journal of Cognitive Neuroscience (MIT Press) 18.2 (2006), 278–297.07–167Kerkhofs, Roel (Radboud U, the Netherlands; [email protected]), Ton Dijkstra, Dorothee J. Chwilla & Ellen R.A. de Bruijn, Testing a model for bilingual semantic priming with interlingual homographs: RT and N400 effects. Brain Research (Elsevier) 1068. 1 (2006), 170–183.07–168Kyung Hwan, Kim & Kim Ja Hyun (U Yonsei, South Korea), Comparison of spatiotemporal cortical activation pattern during visual perception of Korean, English, Chinese words: An event-related potential study. Neuroscience Letters (Elsevier) 394.3 (2006), 227–232.07–169Paradis, Michel (McGill U, Canada; [email protected]), More belles infidels – or why do so many bilingual studies speak with forked tongue?Journal of Neurolinguistics (Elsevier) 19. 3 (2006), 195–208.07–170Poldrack, Russell, A. (U California, Los Angeles, USA; [email protected]), Can cognitive processes be inferred from neuroimaging data? Trends in Cognitive Science (Elsevier) 10.2 (2006), 59–63.07–171Ylinen, Sari (U Helsinki, Finland; [email protected]), Anna Shestakova, Minna Huotilainen, Paavo Alku & Risto Näätänen, Mismatch negativity (MMN) elicited by changes in phoneme length: A cross-linguistic study. Brain Research (Elsevier) 1072.1 (2006), 175–185.07–172Yokoyama Satoru (U Tohoku, Japan),Hideyuki Okamoto, Tadao Miyamoto, Kei Yoshimoto, Jungho Kim, Kazuki Iwata, Hyeonjeong Jeong, Shinya Uchida, Naho Ikuta, Yuko Sassa, Wataru Nakamura, Kaoru Horie, Shigeru Sato & Ryuta Kawashima, Cortical activation in the processing of passive sentences in L1 and L2: An fMRI study. NeuroImage (Elsevier) 30. 2 (2006), 570–579.

scholarly journals Automaticity and Reestablishment of Executive Control—An fMRI Study

2006 ◽  
Vol 18 (8) ◽  
pp. 1331-1342 ◽  
Author(s):  
Andrea Kübler ◽  
Veronica Dixon ◽  
Hugh Garavan
Keyword(s):  
Executive Control ◽  
Dorsolateral Prefrontal Cortex ◽  
Search Task ◽  
Visual Search Task ◽  
Cortical Activation ◽  
Automatic Behavior ◽  
Automatic Response ◽  
Fmri Study ◽  
Dorsolateral Prefrontal

The ability to exert control over automatic behavior is of particular importance as it allows us to interrupt our behavior when the automatic response is no longer adequate or even dangerous. However, despite the literature that exists on the effects of practice on brain activation, little is known about the neuroanatomy involved in reestablishing executive control over previously automatized behavior. We present a visual search task that enabled participants to automatize according to defined criteria within about 3 hr of practice and then required them to reassert control without changing the stimulus set. We found widespread cortical activation early in practice. Activation in all frontal areas and in the inferior parietal lobule decreased significantly with practice. Only selected prefrontal (Brodmann's areas [BAs] 9/46/8) and parietal areas (BAs 39/40) were specifically reactivated when executive control was required, underlining the crucial role of the dorsolateral prefrontal cortex in executive control to guide our behavior.

scholarly journals Hippocampal Contributions to Episodic Encoding: Insights From Relational and Item-Based Learning

2002 ◽  
Vol 88 (2) ◽  
pp. 982-990 ◽  
Author(s):  
Lila Davachi ◽  
Anthony D. Wagner
Keyword(s):  
Working Memory ◽  
Medial Temporal Lobe ◽  
Memory Formation ◽  
Relational Processing ◽  
Behavioral Measures ◽  
Fmri Study ◽  
Episodic Encoding ◽  
Hippocampus Proper ◽  
Temporal Structures ◽  
Cortical Regions

The integrity of the hippocampus and surrounding medial-temporal cortices is critical for episodic memory, with the hippocampus being posited to support relational or configural associative learning. The present event-related functional magnetic resonance imaging (fMRI) study investigated the role of specific medial-temporal lobe structures in learning during relational and item-based processing, as well as the extent to which these structures are engaged during item-based maintenance of stimuli in working memory. fMRI indexed involvement of the hippocampus and underlying cortical regions during performance of two verbal encoding conditions, one that required item-based maintenance of word triplets in working memory and the other that entailed the formation of inter-item associations across the words in each triplet. Sixteen subjects were scanned using a rapid event-related fMRI design while they encountered the item-based and relational processing trials. To examine the correlation between fMRI signal in medial-temporal structures during learning and the subject's subsequent ability to remember the stimuli (a measure of effective memory formation), subjects were administered a yes-no recognition memory test following completion of the encoding scans. Results revealed that the hippocampus proper was engaged during both relational and item-based processing, with relational processing resulting in a greater hippocampal response. By contrast, entorhinal and parahippocampal gyri were differentially engaged during item-based processing, providing strong evidence for a functional neuroanatomic distinction between hippocampal and parahippocampal structures. Analysis of the neural correlates of subsequent memory revealed that activation in the bilateral hippocampus was reliably correlated with behavioral measures of effective memory formation only for those stimuli that were encoded in a relational manner. Taken together, these data provide evidence that the hippocampus, while engaged during item-based working memory maintenance, differentially subserves the relational binding of items into an integrated memory trace so that the experience can be later remembered.

scholarly journals Changes in cortical activation during mirror reading before and after training: an fMRI study of procedural learning

2001 ◽  
Vol 10 (3) ◽  
pp. 207-217 ◽  
Author(s):  
Jan Kassubek ◽  
Klaus Schmidtke ◽  
Hubert Kimmig ◽  
Carl H. Lücking ◽  
Mark W. Greenlee
Keyword(s):  
Procedural Learning ◽  
Cortical Activation ◽  
Fmri Study ◽  
Before And After ◽  
Mirror Reading

Coarse-to-fine Categorization of Visual Scenes in Scene-selective Cortex

2014 ◽  
Vol 26 (10) ◽  
pp. 2287-2297 ◽  
Author(s):  
Benoit Musel ◽  
Louise Kauffmann ◽  
Stephen Ramanoël ◽  
Coralie Giavarini ◽  
Nathalie Guyader ◽  
...  
Keyword(s):  
Visual Analysis ◽  
Retrosplenial Cortex ◽  
Dynamic Scenes ◽  
Spatial Frequencies ◽  
Fmri Study ◽  
Outdoor Scenes ◽  
Computational Data ◽  
Cortical Regions ◽  
First Time ◽  
Coarse To Fine

Neurophysiological, behavioral, and computational data indicate that visual analysis may start with the parallel extraction of different elementary attributes at different spatial frequencies and follows a predominantly coarse-to-fine (CtF) processing sequence (low spatial frequencies [LSF] are extracted first, followed by high spatial frequencies [HSF]). Evidence for CtF processing within scene-selective cortical regions is, however, still lacking. In the present fMRI study, we tested whether such processing occurs in three scene-selective cortical regions: the parahippocampal place area (PPA), the retrosplenial cortex, and the occipital place area. Fourteen participants were subjected to functional scans during which they performed a categorization task of indoor versus outdoor scenes using dynamic scene stimuli. Dynamic scenes were composed of six filtered images of the same scene, from LSF to HSF or from HSF to LSF, allowing us to mimic a CtF or the reverse fine-to-coarse (FtC) sequence. Results showed that only the PPA was more activated for CtF than FtC sequences. Equivalent activations were observed for both sequences in the retrosplenial cortex and occipital place area. This study suggests for the first time that CtF sequence processing constitutes the predominant strategy for scene categorization in the PPA.

Reduced cortical activation in inferior frontal junction in Unverricht–Lundborg disease (EPM1) – A motor fMRI study

2015 ◽  
Vol 111 ◽  
pp. 78-84
Author(s):  
Mervi Könönen ◽  
Nils Danner ◽  
Päivi Koskenkorva ◽  
Reetta Kälviäinen ◽  
Jelena Hyppönen ◽  
...  
Keyword(s):  
Cortical Activation ◽  
Fmri Study ◽  
Inferior Frontal Junction

Moral emotions when reading quotidian circumstances in contexts of violence: an fMRI study

2020 ◽  
pp. 105971232093934
Author(s):  
Daniel Atilano-Barbosa ◽  
Lorena Paredes ◽  
Froylán Enciso ◽  
Erick H Pasaye ◽  
Roberto E Mercadillo
Keyword(s):  
Emotional Experience ◽  
Real Life ◽  
Posterior Cingulate Cortex ◽  
Moral Emotions ◽  
Moral Judgments ◽  
Social Actions ◽  
Fmri Study ◽  
Socially Relevant ◽  
Cortical Regions ◽  
Reference Processing

The increase of violence in Mexico and consequent suffering during the last decades is evident, but its effects over feelings and moral judgments remain uncertain. We used journalistic news showing real-life situations to investigate the effects of facing violence over the experience of four moral emotions which represent powerful impulses for social actions in situations of suffering linked to violence: Negative Compassion, Positive Compassion, Schadenfreude, and Indignation. We evaluate brain activation by using functional magnetic resonance imaging (fMRI) during three cognitive conditions: reading, introspection, and resting. When reading the news, only Indignation-evoking stimuli elicited salient brain activations in the posterior cerebellum, and temporal and parietal cortical regions, whose functions are related to anger experiences and processing of socially relevant circumstances. When introspecting the emotional experience, cerebellar, frontal, parietal, and occipital activations related to self-focused experiences were observed for all emotions. When resting after facing the stimuli, only the Negative Compassion emotion elicited brain activations in the posterior cingulate cortex and precuneus related to emotional self-reference processing; thus, negative compassion may produce more perdurable cognitive-affective effects related to sadness while perceiving suffering in others. Our results may suggest different emotional-based social decisions to face suffering and violence and to motivate pro-social actions in the collectivistic Mexican culture.

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