scholarly journals The effect of object type on building scene imagery – an MEG study

2020 ◽  
Author(s):  
Anna M. Monk ◽  
Gareth R. Barnes ◽  
Eleanor A. Maguire
Keyword(s):  
Conceptual Knowledge ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Superior Temporal Gyrus ◽  
Brain Regions ◽  
High Temporal Resolution ◽  
Neural Responses ◽  
3D Space ◽  
Scene Construction ◽  
The Right

ABSTRACTPrevious studies have reported that some objects evoke a sense of local three-dimensional space (space-defining; SD), while others do not (space-ambiguous; SA), despite being imagined or viewed in isolation devoid of a background context. Moreover, people show a strong preference for SD objects when given a choice of objects with which to mentally construct scene imagery. When deconstructing scenes, people retain significantly more SD objects than SA objects. It therefore seems that SD objects might enjoy a privileged role in scene construction. In the current study, we leveraged the high temporal resolution of magnetoencephalography (MEG) to compare the neural responses to SD and SA objects while they were being used to build imagined scene representations, as this has not been examined before using neuroimaging. On each trial, participants gradually built a scene image from three successive auditorily-presented object descriptions and an imagined 3D space. We then examined the neural dynamics associated with the points during scene construction when either SD or SA objects were being imagined. We found that SD objects elicited theta changes relative to SA objects in two brain regions, the right ventromedial prefrontal cortex (vmPFC) and right superior temporal gyrus (STG). Furthermore, using dynamic causal modelling, we observed that the vmPFC drove STG activity. These findings may indicate that SD objects serve to activate schematic and conceptual knowledge in vmPFC and STG upon which scene representations are then built.

scholarly journals A Fundamental Distinction in Early Neural Processing of Implicit Social Interpretation in Schizophrenia and Bipolar Disorder

2021 ◽  
Author(s):  
Nuno Gonçalo Gomes Fernandes Madeira ◽  
Ricardo Filipe Alves Martins ◽  
João Valente Duarte ◽  
Gabriel Nascimento Ferreira Costa ◽  
António João Ferreira Macedo Santos ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Social Cognitive ◽  
Characteristic Curve ◽  
Superior Temporal Gyrus ◽  
Neural Responses ◽  
Opposite Pattern ◽  
Activation Patterns ◽  
Temporoparietal Junction ◽  
Distinctive Features ◽  
The Right

ABSTRACTBackgroundSocial cognition impairment is a key phenomenon in serious mental disorders such as schizophrenia (SCZ) and bipolar disorder (BPD). Although genetic and neurobiological studies have suggested common neural correlates, here we hypothesized that a fundamental dissociation of social processing occurs at an early level in these conditions.MethodsBased on the hypothesis that key structures in the social brain, namely the temporoparietal junction, should present distinctive features in SCZ and BPD during low-level social judgment, we conducted a case-control study in SCZ (n=20) and BPD (n=20) patients and controls (n=20), using task-based fMRI during a Theory-of-Mind (ToM) visual paradigm leading to interpretation of social meaning based on simple geometric figures.ResultsWe found opposite neural responses in two core ToM regions : SCZ patients showed social content-related deactivation (relative to controls and BPD) of the right supramarginal gyrus, a region which activity is required to overcome egocentric “overmentalizing”, while the opposite pattern was found in BPD; reverse patterns, relative to controls and SCZ, were found in the left posterior superior temporal gyrus, a region involved in inferring other’s intentions. Receiver-operating-characteristic curve analysis showed 88% accuracy in discriminating the two clinical groups based on these neural responses.ConclusionsThese contrasting activation patterns of the temporoparietal junction in SCZ and BPD represent mechanistic differences of social cognitive dysfunction that may be explored as biomarkers or therapeutic targets.

Dissociable brain correlates for depression, anxiety, dissociation, and somatization in depersonalization-derealization disorder

CNS Spectrums ◽  
2013 ◽  
Vol 21 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Erwin Lemche ◽  
Simon A. Surguladze ◽  
Michael J. Brammer ◽  
Mary L. Phillips ◽  
Mauricio Sierra ◽  
...  
Keyword(s):  
Inferior Frontal Gyrus ◽  
Superior Temporal Gyrus ◽  
Brain Regions ◽  
Self Report ◽  
Parahippocampal Gyrus ◽  
Left Inferior Frontal Gyrus ◽  
Symptoms Of Depression ◽  
Caudate Head ◽  
Brain Correlates ◽  
The Right

ObjectiveThe cerebral mechanisms of traits associated with depersonalization-derealization disorder (DPRD) remain poorly understood.MethodHappy and sad emotion expressions were presented to DPRD and non-referred control (NC) subjects in an implicit event-related functional magnetic resonance imaging (fMRI) design, and correlated with self report scales reflecting typical co-morbidities of DPRD: depression, dissociation, anxiety, somatization.ResultsSignificant differences between the slopes of the two groups were observed for somatization in the right temporal operculum (happy) and ventral striatum, bilaterally (sad). Discriminative regions for symptoms of depression were the right pulvinar (happy) and left amygdala (sad). For dissociation, discriminative regions were the left mesial inferior temporal gyrus (happy) and left supramarginal gyrus (sad). For state anxiety, discriminative regions were the left inferior frontal gyrus (happy) and parahippocampal gyrus (sad). For trait anxiety, discriminative regions were the right caudate head (happy) and left superior temporal gyrus (sad).DiscussionThe ascertained brain regions are in line with previous findings for the respective traits. The findings suggest separate brain systems for each trait.ConclusionOur results do not justify any bias for a certain nosological category in DPRD.

Minimization of Common-Mode Voltage of Three-Phase Five-Level NPC Inverter Using 3D Space Vector Modulation

2020 ◽  
Vol 29 (14) ◽  
pp. 2050229 ◽  
Author(s):  
Palanisamy Ramasamy ◽  
Vijayakumar Krishnasamy
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Harmonic Distortion ◽  
Space Vector Modulation ◽  
Space Vector ◽  
Common Mode ◽  
Common Mode Voltage ◽  
3D Space ◽  
Vector Modulation ◽  
Switching State

In this paper, a three-dimensional Space Vector Modulation (3D SVM) is implemented for minimization of Common-Mode Voltage (CMV) of five-level Neutral Point Clamped (NPC) inverter. The 3D SVM control includes all merits of 2D SVM and provides better control compared to other PWM strategies. The switching state vectors are selected based on the nearest vector Switching State Vector (NSV); it selects the switching vectors which are having the minimum CMV level. It leads to minimization of the bearing voltage and protection of the drive from the damage; also this system reduces the total harmonic distortion. The switching time is calculated by reference vector identification with large and small subcubes tracking and prisms tracking in 3D cubic region. The CMV level with 3D SVM scheme is compared with other PWM methods. The simulation and hardware results are verified using Matlab Simulink and FPGA processor.

Path-Tracking Control of Stochastic Quadrotor Aircraft in Three-Dimensional Space

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
K. D. Do
Keyword(s):  
Tracking Control ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Path Tracking ◽  
Effective Control ◽  
Practical Implementation ◽  
Unit Quaternion ◽  
3D Space ◽  
Quadrotor Aircraft ◽  
Deterministic Components

Despite the fact that environmental loads (forces and moments) induced by wind on quadrotor vertical take-off and landing (VTOL) aircraft consist of both deterministic and stochastic components, all existing works on controlling the aircraft either ignore these loads or treat them as deterministic. This ignorance or treatment deteriorates the control performance in a practical implementation. This paper presents a constructive design of controllers for a quadrotor aircraft to track a reference path in three-dimensional (3D) space under both deterministic and stochastic disturbances. A combination of Euler angles and unit-quaternion for the attitude representation of the aircraft is used to result in an effective control design, and to achieve path-tracking control results. Weak and strong nonlinear Lyapunov functions are introduced to overcome difficulties caused by underactuation and Hessian terms induced by stochastic differentiation rule. To overcome the inherent underactuation of the aircraft, the roll and pitch angles of the aircraft are considered as immediate controls. Potential projection functions are introduced to design estimates of the deterministic components and covariances of the stochastic components. Simulations illustrate the results.

Visional Attentional Allocation of Top-down and Bottom-up Cues in Three-Dimensional Space

2011 ◽  
Vol 179-180 ◽  
pp. 1322-1326
Author(s):  
Ru Ting Xia
Keyword(s):  
Visual Attention ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Depth Information ◽  
Top Down ◽  
Bottom Up ◽  
Attentional Allocation ◽  
3D Space ◽  
Target Locations ◽  
Three Dimensional Space

The aim of the present experiment was to investigate visual attentional allocation of top-down and bottom-up cues in three-dimensional (3D) space. Near and far stimuli were used by a 3D attention measurement apparatus. Two experiments were conducted in order to examine top-down and bottom-up controls of visual attention. In the experiment 1, the cue about the location of a target by means of location information. In the experiment 2, color cue by brief change of color at target locations was presented. Observers were required to judge whether the target presented nearer than fixation point or further than it. The results in experiment 1 and experiment 2 show that both location and color cue have the effect on reaction time, and that shift of attention were faster from far to near than the reverse. These findings suggest that (1) attention in 3D space might be operated with both location and color controls included the depth information, (2) the shift of visual attention in 3D space has an asymmetric characteristic in depth.

scholarly journals V-Factor Indicator in the Assessment of the Change in the Attractiveness of View as a Result of the Implementation of a Specific Planning Scenario

2019 ◽  
Vol 8 (2) ◽  
pp. 78
Author(s):  
Magda Pluta ◽  
Bartosz Mitka
Keyword(s):  
Factor Analysis ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Observation Point ◽  
View Factor ◽  
Factor V ◽  
Average Value ◽  
3D Space ◽  
The Aesthetic ◽  
Special Points

This paper describes the algorithm of the view factor (V-factor). It is based on an analysis of visibility, taking into account the attractiveness of the observed elements in a three-dimensional space. The results of the V-factor analysis provide input for the decision-making process when selecting the most advantageous planning scenario so that the harmony of landscape and ecological balance can be maintained. The V-factor indicator can be successfully used in the process of spatial planning, in particular, at the stage of determining the parameters of new buildings and lines of sight between planned buildings. The purpose of the indicator is to determine the numerical values for observation points, thus facilitating a comparative assessment of the attractiveness of view available from the special points in space. The analysis uses a 3D space model that includes an integrated existing and planning state designed on the basis of planning scenarios. The V-factor analysis takes into account the distance of the observation point from the observed object, vertical and horizontal angles of observation, and the aesthetic value of the observed object. As a result, an average value of the V-factor indicator was obtained for each planning scenario, which facilitated the determination of the more beneficial one in terms of the attractiveness of view.

scholarly journals Cortical Regions Involved in the Generation of Musical Structures during Improvisation in Pianists

2007 ◽  
Vol 19 (5) ◽  
pp. 830-842 ◽  
Author(s):  
Sara L. Bengtsson ◽  
Mihály Csíkszentmihályi ◽  
Fredrik Ullén
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Response Selection ◽  
Premotor Cortex ◽  
Posterior Part ◽  
Superior Temporal Gyrus ◽  
Brain Regions ◽  
Dorsolateral Prefrontal ◽  
The Right ◽  
Musical Creation

Studies on simple pseudorandom motor and cognitive tasks have shown that the dorsolateral prefrontal cortex and rostral premotor areas are involved in free response selection. We used functional magnetic resonance imaging to investigate whether these brain regions are also involved in free generation of responses in a more complex creative behavior: musical improvisation. Eleven professional pianists participated in the study. In one condition, Improvise, the pianist improvised on the basis of a visually displayed melody. In the control condition, Reproduce, the participant reproduced his previous improvisation from memory. Participants were able to reproduce their improvisations with a high level of accuracy, and the contrast Improvise versus Reproduce was thus essentially matched in terms of motor output and sensory feedback. However, the Improvise condition required storage in memory of the improvisation. We therefore also included a condition FreeImp, where the pianist improvised but was instructed not to memorize his performance. To locate brain regions involved in musical creation, we investigated the activations in the Improvise-Reproduce contrast that were also present in FreeImp contrasted with a baseline rest condition. Activated brain regions included the right dorsolateral prefrontal cortex, the presupplementary motor area, the rostral portion of the dorsal premotor cortex, and the left posterior part of the superior temporal gyrus. We suggest that these regions are part of a network involved in musical creation, and discuss their possible functional roles.

scholarly journals Alterations of Regional Homogeneity in the Mild and Moderate Stages of Parkinson’s Disease

2021 ◽  
Vol 13 ◽  
Author(s):  
Junli Li ◽  
Haiyan Liao ◽  
Tianyu Wang ◽  
Yuheng Zi ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Superior Temporal Gyrus ◽  
Blood Oxygen Level Dependent ◽  
Brain Regions ◽  
Regional Homogeneity ◽  
Neural Function ◽  
Precentral Gyrus ◽  
Orbital Gyrus ◽  
The Right

Objectives: This study aimed to investigate alterations in regional homogeneity (ReHo) in early Parkinson’s disease (PD) at different Hoehn and Yahr (HY) stages and to demonstrate the relationships between altered brain regions and clinical scale scores.Methods: We recruited 75 PD patients, including 43 with mild PD (PD-mild; HY stage: 1.0–1.5) and 32 with moderate PD (PD-moderate; HY stage: 2.0–2.5). We also recruited 37 age- and sex-matched healthy subjects as healthy controls (HC). All subjects underwent neuropsychological assessments and a 3.0 Tesla magnetic resonance scanning. Regional homogeneity of blood oxygen level-dependent (BOLD) signals was used to characterize regional cerebral function. Correlative relationships between mean ReHo values and clinical data were then explored.Results: Compared to the HC group, the PD-mild group exhibited increased ReHo values in the right cerebellum, while the PD-moderate group exhibited increased ReHo values in the bilateral cerebellum, and decreased ReHo values in the right superior temporal gyrus, the right Rolandic operculum, the right postcentral gyrus, and the right precentral gyrus. Reho value of right Pre/Postcentral was negatively correlated with HY stage. Compared to the PD-moderate group, the PD-mild group showed reduced ReHo values in the right superior orbital gyrus and the right rectus, in which the ReHo value was negatively correlated with cognition.Conclusion: The right superior orbital gyrus and right rectus may serve as a differential indicator for mild and moderate PD. Subjects with moderate PD had a greater scope for ReHo alterations in the cortex and compensation in the cerebellum than those with mild PD. PD at HY stages of 2.0–2.5 may already be classified as Braak stages 5 and 6 in terms of pathology. Our study revealed the different patterns of brain function in a resting state in PD at different HY stages and may help to elucidate the neural function and early diagnosis of patients with PD.

scholarly journals Increased functional connectivity of the intraparietal sulcus underlies the attenuation of numerosity estimations for self-generated words

2020 ◽  
Author(s):  
Giedre Stripeikyte ◽  
Michael Pereira ◽  
Giulio Rognini ◽  
Jevita Potheegadoo ◽  
Olaf Blanke ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Cognitive Functions ◽  
Supplementary Motor Area ◽  
Superior Temporal Gyrus ◽  
Intraparietal Sulcus ◽  
Neural Responses ◽  
Passive Condition ◽  
Sensorimotor Processing ◽  
Active Condition ◽  
The Right

ABSTRACTPrevious studies have shown that self-generated stimuli in auditory, visual, and somatosensory domains are attenuated, producing decreased behavioral and neural responses compared to the same stimuli that are externally generated. Yet, whether such attenuation also occurs for higher-level cognitive functions beyond sensorimotor processing remains unknown. In this study, we assessed whether cognitive functions such as numerosity estimations are subject to attenuation. We designed a task allowing the controlled comparison of numerosity estimations for self (active condition) and externally (passive condition) generated words. Our behavioral results showed a larger underestimation of self-compared to externally-generated words, suggesting that numerosity estimations for self-generated words are attenuated. Moreover, the linear relationship between the reported and actual number of words was stronger for self-generated words, although the ability to track errors about numerosity estimations was similar across conditions. Neuroimaging results revealed that numerosity underestimation involved increased functional connectivity between the right intraparietal sulcus and an extended network (bilateral supplementary motor area, left inferior parietal lobule and left superior temporal gyrus) when estimating the number of self vs. externally generated words. We interpret our results in light of two models of attenuation and discuss their perceptual versus cognitive origins.

scholarly journals The role of hippocampal-vmPFC neural dynamics in building mental representations

2020 ◽  
Author(s):  
Anna M. Monk ◽  
Marshall A. Dalton ◽  
Gareth R. Barnes ◽  
Eleanor A. Maguire
Keyword(s):  
Episodic Memory ◽  
Brain Regions ◽  
High Temporal Resolution ◽  
Cognitive Domains ◽  
3D Space ◽  
Initial Stage ◽  
Hippocampal Activity ◽  
Two Stages ◽  
2D Space

AbstractThe hippocampus and ventromedial prefrontal cortex (vmPFC) play key roles in numerous cognitive domains including mind-wandering, episodic memory and imagining the future. Perspectives differ on precisely how they support these diverse functions, but there is general agreement that it involves constructing representations comprised of numerous elements. Visual scenes have been deployed extensively in cognitive neuroscience because they are paradigmatic multi-element stimuli. However, it remains unclear whether scenes, rather than other types of multi-feature stimuli, preferentially engage hippocampus and vmPFC. Here we leveraged the high temporal resolution of magnetoencephalography to test participants as they gradually built scene imagery from three successive auditorily-presented object descriptions and an imagined 3D space. This was contrasted with constructing mental images of non-scene arrays that were composed of three objects and an imagined 2D space. The scene and array stimuli were, therefore, highly matched, and this paradigm permitted a closer examination of step-by-step mental construction than has been undertaken previously. We observed modulation of theta power in our two regions of interest – anterior hippocampus during the initial stage, and in vmPFC during the first two stages, of scene relative to array construction. Moreover, the scene-specific anterior hippocampal activity during the first construction stage was driven by the vmPFC, with mutual entrainment between the two brain regions thereafter. These findings suggest that hippocampal and vmPFC neural activity is especially tuned to scene representations during the earliest stage of their formation, with implications for theories of how these brain areas enable cognitive functions such as episodic memory.

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