scholarly journals Objects seen as scenes: neural circuitry for attending whole or parts

2019 ◽  
Author(s):  
Mitchell Valdés-Sosa ◽  
Marlis Ontivero-Ortega ◽  
Jorge Iglesias-Fuster ◽  
Agustin Lage-Castellanos ◽  
Jinnan Gong ◽  
...  
Keyword(s):  
Local Level ◽  
Temporal Cortex ◽  
Neural Circuitry ◽  
Cortical Network ◽  
Hierarchical Level ◽  
List Type ◽  
Shape Information ◽  
Illusory Conjunctions ◽  
Level Information ◽  
Cortical Regions

AbstractDepending on our goals, we pay attention to the global shape of an object or to the local shape of its parts, since it’s difficult to do both at once. This typically effortless process can be impaired in disease. However, it is not clear which cortical regions carry the information needed to constrain shape processing to a chosen global/local level. Here, novel stimuli were used to dissociate functional MRI responses to global and local shapes. This allowed identification of cortical regions containing information about level (independent from shape). Crucially, these regions overlapped part of the cortical network implicated in scene processing. As expected, shape information (independent of level) was mainly located in category-selective areas specialized for object- and face-processing. Regions with the same informational profile were strongly linked (as measured by functional connectivity), but were weak when the profiles diverged. Specifically, in the ventral-temporal-cortex (VTC) regions favoring level and shape were consistently separated by the mid-fusiform sulcus (MFS). These regions also had limited crosstalk despite their spatial proximity, thus defining two functional pathways within VTC. We hypothesize that object hierarchical level is processed by neural circuitry that also analyses spatial layout in scenes, contributing to the control of the spatial-scale used for shape recognition. Use of level information tolerant to shape changes could guide whole/part attentional selection but facilitate illusory shape/level conjunctions under impoverished vision.Significance statementOne daily engages hierarchically organized objects (e.g. face-eyes-eyelashes). Their perception is commonly studied with global shapes composed by of local shapes. Seeing shape at one level is easy, but difficult for both at once. How can the brain guide attention to one level? Here using novel stimuli that dissociate different levels over time and examining local patterns of brain-activity, we found that the level and shape of visual objects were represented into segregated sets of cortical regions, each connected into their own pathway. Level information was found in part of the cortical network known to process scenes. Coding of object-level independently from shape could participate in guiding sustained attention within objects, eliminating interference from irrelevant levels. It could also help produce “illusory conjunctions” (perceptual migration of a shape to the wrong level) when attention is limited.HighlightsModified Navon figures allow dissociation in time of fMRI responses for the global/local levels.Shape-invariant hierarchical level information was found in scenes selective areas, whereas level-invariant shape information was found in object- and faces- selective areas.Level and shape regions were divided by the mid-fusiform sulcus (MFS) in VTC cortex, and each type of region connected into its own pathway.Having separate level/shape pathways could facilitate selective-attention, but foster illusory conjunctions.

Imaging Usual Addictions: Tobacco, Canabis and Alcohol

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
C. Leroy ◽  
S. Chanraud ◽  
E. Artiges ◽  
C. Martelli ◽  
A. Cachia ◽  
...  
Keyword(s):  
White Matter ◽  
Psychosocial Functioning ◽  
Grey Matter ◽  
Diffusion Imaging ◽  
Temporal Cortex ◽  
List Type ◽  
Dopamine Level ◽  
Type Number ◽  
Positron Emission ◽  
Brain Microstructure

Background:Brain models of drug addiction are being tackled in humans, using PET and MRI.Results:1.Whereas tobacco and cannabis do not interact directly with dopamine sites, positron emission tomography detected lower availability in sites regulating the catecholamines homeostasis, notably in dopamine transporter sites in striatal and in extrastriatal regions. This further supports repeated and long term substance use progress towards an adaptative diminished basal dopamine level that would contribute to the switch to an addicted brain.2.Alcohol: abnormalities in brain macro- and micro- structure were searched in detoxified alcohol-dependents with preserved psychosocial functioning:-Brain function (fMRI): fronto-cerebellar overactivation detected during an auditory language task in alcohol-dependents may reflect the compensatory effort required for patients to maintain the same level of performance as controls.-Brain macrostructure (MRI). Widespread lower white matter volumes, and lower grey matter volumes in the frontal lobe, insula, hippocampus, thalami and cerebellum, were detected. Poorer neuropsychological performance correlated with smaller grey matter volumes in these regions and with lower white matter volume in the brainstem.-Brain microstructure (DTI): tractography of white matter fiber bundles revealed that brainstem bundles alteration may contribute to cognitive flexibility impairment. Regression analyses showed memory scores were related to brain microstructure in parahippocampal areas, frontal cortex, and left temporal cortex. This suggest diffusion imaging (DTI) is a useful probe to early alcohol-induced brain alterations.Conclusion:While indices of dopamine down-regulation are consistency detected in several drug addictions, even “socially-adapted” alcohol dependence may induce change in brain structure.Psychol Med. 1998 28:1039-48.Neuropsychopharmacology. 2007 32:429-38.IEEE Trans Med Imaging. 2007 26:553-65J Nucl Med. 2007 48:538-46.Neuropsychopharmacology (Chanraud S et al., 2008 Jul 9. [Epub ahead of print]).J Clin Psychopharmacol (Leroy C et al, in press).

Modulation of the Visual Word Retrieval System in Writing: A Functional MRI Study on the Japanese Orthographies

2002 ◽  
Vol 14 (1) ◽  
pp. 104-115 ◽  
Author(s):  
Kimihiro Nakamura ◽  
Manabu Honda ◽  
Shigeru Hirano ◽  
Tatsuhide Oga ◽  
Nobukatsu Sawamoto ◽  
...  
Keyword(s):  
Retrieval System ◽  
Temporal Cortex ◽  
Visual Word ◽  
Word Retrieval ◽  
Anterior Cingulate ◽  
Input Stimulus ◽  
Semantic Judgment ◽  
Cortical Regions ◽  
Mri Study ◽  
Mental Recall

We used functional magnetic resonance imaging (fMRI) to examine whether the act of writing involves different neuro-psychological mechanisms between the two script systems of the Japanese language: kanji (ideogram) and kana (phonogram). The main experiments employed a 2 × 2 factorial design that comprised writing-to-dictation and visual mental recall for kanji and kana. For both scripts, the actual writing produced a widespread fronto-parietal activation in the left hemisphere. Especially, writing of kanji activated the left posteroinferior temporal cortex (lPITC), whereas that of kana also yielded a trend of activation in the same area. Mental recall for both scripts activated similarly the left parieto-temporal regions including the lPITC. The writing versus mental recall comparison revealed greater activations in the left sensorimotor areas and right cerebellum. The kanji versus kana comparison showed increased responses in the left prefrontal and anterior cingulate areas. Especially, the lPITC showed a significant task-by-script interaction. Two additional control tasks, repetition (REP) and semantic judgment (SJ), activated the bilateral perisylvian areas, but enhanced the lPITC response only weakly. These results suggest that writing of the ideographic and phonographic scripts, although using the largely same cortical regions, each modulates the visual word-retrieval system according to their graphic features. Furthermore, comparisons with two additional tasks indicate that the activity of the lPITC increases especially in expressive language operations regardless of sensory modalities of the input stimulus.

scholarly journals Intolerance of uncertainty is associated with heightened responding in the prefrontal cortex during instructed threat of shock

2020 ◽  
Author(s):  
Jayne Morriss ◽  
Tiffany Bell ◽  
Nicolò Biagi ◽  
Tom Johnstone ◽  
Carien M. van Reekum
Keyword(s):  
Prefrontal Cortex ◽  
Anxiety Disorder ◽  
Intolerance Of Uncertainty ◽  
Neural Circuitry ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Prefrontal Cortical ◽  
Cortical Regions ◽  
Rostral Prefrontal Cortex ◽  
Threat Of Shock

AbstractHeightened responding to uncertain threat is associated with anxiety disorder pathology. Here, we sought to determine if individual differences in self-reported intolerance of uncertainty (IU) underlie differential recruitment of neural circuitry during instructed threat of shock (n = 42). During the task, cues signalled uncertain threat of shock (50%) or certain safety from shock. Ratings, skin conductance and functional magnetic resonance imaging was acquired. Overall, participants displayed greater amygdala activation to uncertain threat vs. safe cues, in the absence of an effect of IU. However, we found that high was associated with greater activity in the medial prefrontal cortex and dorsomedial rostral prefrontal cortex to uncertain threat vs safe cues. These findings suggest that, during instructed threat of shock, IU is specifically related, over trait anxiety, to activation in prefrontal cortical regions. Taken together, these findings highlight the potential of self-reported IU in identifying mechanisms that may be related to conscious threat appraisal and anxiety disorder pathology.

scholarly journals Training neural networks to recognize speech increased their correspondence to the human auditory pathway but did not yield a shared hierarchy of acoustic features

2021 ◽  
Author(s):  
Jessica A.F. Thompson ◽  
Yoshua Bengio ◽  
Elia Formisano ◽  
Marc Schönwiesner
Keyword(s):  
Neural Networks ◽  
Recognition Task ◽  
Single Layer ◽  
Auditory Pathway ◽  
7 Tesla ◽  
List Type ◽  
Acoustic Features ◽  
Visual Areas ◽  
Cortical Regions ◽  
Fully Connected

AbstractThe correspondence between the activity of artificial neurons in convolutional neural networks (CNNs) trained to recognize objects in images and neural activity collected throughout the primate visual system has been well documented. Shallower layers of CNNs are typically more similar to early visual areas and deeper layers tend to be more similar to later visual areas, providing evidence for a shared representational hierarchy. This phenomenon has not been thoroughly studied in the auditory domain. Here, we compared the representations of CNNs trained to recognize speech (triphone recognition) to 7-Tesla fMRI activity collected throughout the human auditory pathway, including subcortical and cortical regions, while participants listened to speech. We found no evidence for a shared representational hierarchy of acoustic speech features. Instead, all auditory regions of interest were most similar to a single layer of the CNNs: the first fully-connected layer. This layer sits at the boundary between the relatively task-general intermediate layers and the highly task-specific final layers. This suggests that alternative architectural designs and/or training objectives may be needed to achieve fine-grained layer-wise correspondence with the human auditory pathway.HighlightsTrained CNNs more similar to auditory fMRI activity than untrainedNo evidence of a shared representational hierarchy for acoustic featuresAll ROIs were most similar to the first fully-connected layerCNN performance on speech recognition task positively associated with fmri similarity

scholarly journals The Human Intraparietal Sulcus Modulates Task-Evoked Functional Connectivity

2019 ◽  
Vol 30 (3) ◽  
pp. 875-887
Author(s):  
Kai Hwang ◽  
James M Shine ◽  
Dillan Cellier ◽  
Mark D’Esposito
Keyword(s):  
Functional Connectivity ◽  
Temporal Cortex ◽  
Brain Regions ◽  
Intraparietal Sulcus ◽  
Top Down ◽  
Adaptive Communication ◽  
Wide Range ◽  
Functional Connectivity Strength ◽  
Ventral Temporal Cortex ◽  
Cortical Regions

Abstract Past studies have demonstrated that flexible interactions between brain regions support a wide range of goal-directed behaviors. However, the neural mechanisms that underlie adaptive communication between brain regions are not well understood. In this study, we combined theta-burst transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging to investigate the sources of top-down biasing signals that influence task-evoked functional connectivity. Subjects viewed sequences of images of faces and buildings and were required to detect repetitions (2-back vs. 1-back) of the attended stimuli category (faces or buildings). We found that functional connectivity between ventral temporal cortex and the primary visual cortex (VC) increased during processing of task-relevant stimuli, especially during higher memory loads. Furthermore, the strength of functional connectivity was greater for correct trials. Increases in task-evoked functional connectivity strength were correlated with increases in activity in multiple frontal, parietal, and subcortical (caudate and thalamus) regions. Finally, we found that TMS to superior intraparietal sulcus (IPS), but not to primary somatosensory cortex, decreased task-specific modulation in connectivity patterns between the primary VC and the parahippocampal place area. These findings demonstrate that the human IPS is a source of top-down biasing signals that modulate task-evoked functional connectivity among task-relevant cortical regions.

Auditory–Articulatory Neural Alignment between Listener and Speaker during Verbal Communication

2019 ◽  
Vol 30 (3) ◽  
pp. 942-951 ◽  
Author(s):  
Lanfang Liu ◽  
Yuxuan Zhang ◽  
Qi Zhou ◽  
Douglas D Garrett ◽  
Chunming Lu ◽  
...  
Keyword(s):  
Speech Processing ◽  
Auditory Processing ◽  
Information Transfer ◽  
Temporal Cortex ◽  
Real Life ◽  
Hierarchical Organization ◽  
Speech Comprehension ◽  
Level Information ◽  
Motor Information ◽  
High Level

Abstract Whether auditory processing of speech relies on reference to the articulatory motor information of speaker remains elusive. Here, we addressed this issue under a two-brain framework. Functional magnetic resonance imaging was applied to record the brain activities of speakers when telling real-life stories and later of listeners when listening to the audio recordings of these stories. Based on between-brain seed-to-voxel correlation analyses, we revealed that neural dynamics in listeners’ auditory temporal cortex are temporally coupled with the dynamics in the speaker’s larynx/phonation area. Moreover, the coupling response in listener’s left auditory temporal cortex follows the hierarchical organization for speech processing, with response lags in A1+, STG/STS, and MTG increasing linearly. Further, listeners showing greater coupling responses understand the speech better. When comprehension fails, such interbrain auditory-articulation coupling vanishes substantially. These findings suggest that a listener’s auditory system and a speaker’s articulatory system are inherently aligned during naturalistic verbal interaction, and such alignment is associated with high-level information transfer from the speaker to the listener. Our study provides reliable evidence supporting that references to the articulatory motor information of speaker facilitate speech comprehension under a naturalistic scene.

scholarly journals Assessing the use and understanding of the Portuguese Heat–Health Warning System (ÍCARO)

2019 ◽  
Vol 29 (Supplement_4) ◽  
Author(s):  
A Leite ◽  
A J Santos ◽  
S Silva ◽  
B Nunes ◽  
R Mexia ◽  
...  
Keyword(s):  
Local Level ◽  
Warning System ◽  
Action Plans ◽  
Structured Interviews ◽  
Health Warning ◽  
Key Stakeholders ◽  
Level Information ◽  
Health Action ◽  
Mortality Forecasts ◽  
Related Mortality

Abstract Background Heatwaves can lead to increased mortality. Portugal has a Heat-Health Warning System (HHWS) in place (ÍCARO system). Researchers at the Instituto Ricardo Jorge send a daily report with heat-related mortality forecasts to key stakeholders (e.g. Heat-Health Action Plans (HHAP) staff). HHAP practitioners issue warnings and implement measures to prevent heatwaves-related mortality. ICARO is amongst the recommended data sources to assess risk and issue warnings but its use and understanding is unknown. Therefore, we aimed to assess ÍCARO’s use and understanding by key HHAP practitioners. Methods We conducted semi-structured interviews with national and regional HHAP practitioners. Interviews were recorded, transcribed, and analysed using thematic content analysis. Intercoder reliability was applied to a sample of segments from 5 of 6 interviews. Results We conducted 6 interviews with 9 professionals (mean time 52 minutes). We identified 4 categories: Report’s content and presentation, Report’s reception and communication, ÍCARO and risk assessment, Other issues. Practitioners use ÍCARO and perceived it as very relevant tool. However, they mentioned several questions on its interpretation. Practitioners also felt their questions were not fully answered, given researchers’ use of statistical terms. Finally, practitioners referred the need to assess risk at the local level, information not currently provided. We also identified the need for improved communication and report’s clarity. Conclusions Our study stresses the need for an integrated collaboration between experts within HHWS and HHAP. Despite ICARO’s understanding being challenging, practitioners consider it a relevant tool. Researchers should use less statistical language and clarify ÍCARO interpretation. Practitioners’ needs should be considered when developing or revising tools. We are currently implementing some of these recommendations in an attempt to close the gap between researchers and practitioners. Key messages Portuguese Heat–Health Action Plans practitioners use heat-related mortality forecasts (ICARO) and perceived it as very relevant instrument. However there find ICARO’s interpretation challenging. Portuguese Heat/Health Action Plans Practitioners’ needs should be considered when revising or developing tools, and notes should be added to clarify statistical/technical concepts.

scholarly journals Comparison of CORINE Land Cover Data with National Statistics and the Possibility to Record This Data on a Local Scale—Case Studies from Slovakia

2020 ◽  
Vol 12 (15) ◽  
pp. 2484
Author(s):  
Vladimír Falťan ◽  
František Petrovič ◽  
Ján Oťaheľ ◽  
Ján Feranec ◽  
Michal Druga ◽  
...  
Keyword(s):  
Land Cover ◽  
Case Studies ◽  
Agricultural Land ◽  
Local Level ◽  
Hierarchical Level ◽  
Minimum Width ◽  
Corine Land Cover ◽  
The Third ◽  
National Statistics ◽  
Local Case

Monitoring of land cover (LC) provides important information of actual land use (LU) and landscape dynamics. LC research results depend on the size of the area, purpose and applied methodology. CORINE Land Cover (CLC) data is one of the most important sources of LU data from a European perspective. Our research compares official CLC data (third hierarchical level of nomenclature at a scale of 1:100,000) and national statistics (NS) of LU in Slovakia between 2000 and 2018 at national, county, and local levels. The most significant differences occurred in arable land and permanent grassland, which is also related to the recording method and the development of agricultural land management. Due to the abandonment of agricultural areas, a real recorded increase in forest cover due to forest succession was not introduced in the official records of Land register. New modification of CLC methodology for identifying LC classes at a scale of 1:10,000 and fifth hierarchical level of CLC is firstly applied for local case studies representing lowland, basin, and mountain landscape. The size of the least identified and simultaneously recorded area was established at 0.1 ha the minimum width of a polygon was established at 10 m, the minimum recorded width of linear elements such as communications was established at 2 m. The use of the fifth CLC level in the case studies areas generated average boundary density 17.2 km/km2, comparing to the 2.6 km/km2 of the third level. Therefore, when measuring the density of spatial information by the polygon boundary lengths, the fifth level carries 6.6 times more information than the third level. Detailed investigation of LU affords better verification of national statistics data at a local level. This study also contributes to a more detailed recording of the current state of the Central European landscape and its changes.

scholarly journals Information Integration and Mesoscopic Cortical Connectivity during Propofol Anesthesia

2020 ◽  
Vol 132 (3) ◽  
pp. 504-524 ◽  
Author(s):  
Zhenhu Liang ◽  
Lei Cheng ◽  
Shuai Shao ◽  
Xing Jin ◽  
Tao Yu ◽  
...  
Keyword(s):  
Mutual Information ◽  
Information Integration ◽  
Path Length ◽  
Cortical Network ◽  
Clustering Coefficient ◽  
Loss Of Consciousness ◽  
Cortical Connectivity ◽  
Cortical Regions ◽  
Network Metrics ◽  
Unconscious State

Abstract Background The neurophysiologic mechanisms of propofol-induced loss of consciousness have been studied in detail at the macro (scalp electroencephalogram) and micro (spiking or local field potential) scales. However, the changes in information integration and cortical connectivity during propofol anesthesia at the mesoscopic level (the cortical scale) are less clear. Methods The authors analyzed electrocorticogram data recorded from surgical patients during propofol-induced unconsciousness (n = 9). A new information measure, genuine permutation cross mutual information, was used to analyze how electrocorticogram cross-electrode coupling changed with electrode-distances in different brain areas (within the frontal, parietal, and temporal regions, as well as between the temporal and parietal regions). The changes in cortical networks during anesthesia—at nodal and global levels—were investigated using clustering coefficient, path length, and nodal efficiency measures. Results In all cortical regions, and in both wakeful and unconscious states (early and late), the genuine permutation cross mutual information and the percentage of genuine connections decreased with increasing distance, especially up to about 3 cm. The nodal cortical network metrics (the nodal clustering coefficients and nodal efficiency) decreased from wakefulness to unconscious state in the cortical regions we analyzed. In contrast, the global cortical network metrics slightly increased in the early unconscious state (the time span from loss of consciousness to 200 s after loss of consciousness), as compared with wakefulness (normalized average clustering coefficient: 1.05 ± 0.01 vs. 1.06 ± 0.03, P = 0.037; normalized average path length: 1.02 ± 0.01 vs. 1.04 ± 0.01, P = 0.021). Conclusions The genuine permutation cross mutual information reflected propofol-induced coupling changes measured at a cortical scale. Loss of consciousness was associated with a redistribution of the pattern of information integration; losing efficient global information transmission capacity but increasing local functional segregation in the cortical network. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

scholarly journals Large-scale Cortical Network Properties Predict Future Sound-to-Word Learning Success

2012 ◽  
Vol 24 (5) ◽  
pp. 1087-1103 ◽  
Author(s):  
John Patrick Sheppard ◽  
Ji-Ping Wang ◽  
Patrick C. M. Wong
Keyword(s):  
Word Learning ◽  
Large Scale ◽  
Functional Organization ◽  
Temporal Cortex ◽  
Spoken Language ◽  
Cortical Network ◽  
Functional Networks ◽  
Network Organization ◽  
Learning Abilities ◽  
Network Properties

The human brain possesses a remarkable capacity to interpret and recall novel sounds as spoken language. These linguistic abilities arise from complex processing spanning a widely distributed cortical network and are characterized by marked individual variation. Recently, graph theoretical analysis has facilitated the exploration of how such aspects of large-scale brain functional organization may underlie cognitive performance. Brain functional networks are known to possess small-world topologies characterized by efficient global and local information transfer, but whether these properties relate to language learning abilities remains unknown. Here we applied graph theory to construct large-scale cortical functional networks from cerebral hemodynamic (fMRI) responses acquired during an auditory pitch discrimination task and found that such network properties were associated with participants' future success in learning words of an artificial spoken language. Successful learners possessed networks with reduced local efficiency but increased global efficiency relative to less successful learners and had a more cost-efficient network organization. Regionally, successful and less successful learners exhibited differences in these network properties spanning bilateral prefrontal, parietal, and right temporal cortex, overlapping a core network of auditory language areas. These results suggest that efficient cortical network organization is associated with sound-to-word learning abilities among healthy, younger adults.

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