scholarly journals Abnormalities of object visual processing in body dysmorphic disorder

2011 ◽  
Vol 41 (11) ◽  
pp. 2385-2397 ◽  
Author(s):  
J. D. Feusner ◽  
E. Hembacher ◽  
H. Moller ◽  
T. D. Moody
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Body Dysmorphic Disorder ◽  
High Spatial Frequency ◽  
Brain Activation ◽  
Occipital Cortex ◽  
Blood Oxygen Level Dependent ◽  
Lower Activity ◽  
Parahippocampal Gyrus ◽  
Blood Oxygen Level

BackgroundIndividuals with body dysmorphic disorder (BDD) may have perceptual distortions for their appearance. Previous studies suggest imbalances in detailed relative to configural/holistic visual processing when viewing faces. No study has investigated the neural correlates of processing non-symptom-related stimuli. The objective of this study was to determine whether individuals with BDD have abnormal patterns of brain activation when viewing non-face/non-body object stimuli.MethodFourteen medication-free participants with DSM-IV BDD and 14 healthy controls participated. We performed functional magnetic resonance imaging (fMRI) while participants matched photographs of houses that were unaltered, contained only high spatial frequency (HSF, high detail) information or only low spatial frequency (LSF, low detail) information. The primary outcome was group differences in blood oxygen level-dependent (BOLD) signal changes.ResultsThe BDD group showed lower activity in the parahippocampal gyrus, lingual gyrus and precuneus for LSF images. There were greater activations in medial prefrontal regions for HSF images, although no significant differences when compared to a low-level baseline. Greater symptom severity was associated with lower activity in the dorsal occipital cortex and ventrolateral prefrontal cortex for normal spatial frequency (NSF) and HSF images.ConclusionsIndividuals with BDD have abnormal brain activation patterns when viewing objects. Hypoactivity in visual association areas for configural and holistic (low detail) elements and abnormal allocation of prefrontal systems for details are consistent with a model of imbalances in global versus local processing. This may occur not only for appearance but also for general stimuli unrelated to their symptoms.

scholarly journals Anorexia nervosa and body dysmorphic disorder are associated with abnormalities in processing visual information

2015 ◽  
Vol 45 (10) ◽  
pp. 2111-2122 ◽  
Author(s):  
W. Li ◽  
T. M. Lai ◽  
C. Bohon ◽  
S. K. Loo ◽  
D. McCurdy ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Spatial Frequency ◽  
Visual Processing ◽  
Visual Information ◽  
Body Dysmorphic Disorder ◽  
High Spatial Frequency ◽  
Event Related Potentials ◽  
Visual Stream ◽  
N170 Component ◽  
Related Potentials

BackgroundAnorexia nervosa (AN) and body dysmorphic disorder (BDD) are characterized by distorted body image and are frequently co-morbid with each other, although their relationship remains little studied. While there is evidence of abnormalities in visual and visuospatial processing in both disorders, no study has directly compared the two. We used two complementary modalities – event-related potentials (ERPs) and functional magnetic resonance imaging (fMRI) – to test for abnormal activity associated with early visual signaling.MethodWe acquired fMRI and ERP data in separate sessions from 15 unmedicated individuals in each of three groups (weight-restored AN, BDD, and healthy controls) while they viewed images of faces and houses of different spatial frequencies. We used joint independent component analyses to compare activity in visual systems.ResultsAN and BDD groups demonstrated similar hypoactivity in early secondary visual processing regions and the dorsal visual stream when viewing low spatial frequency faces, linked to the N170 component, as well as in early secondary visual processing regions when viewing low spatial frequency houses, linked to the P100 component. Additionally, the BDD group exhibited hyperactivity in fusiform cortex when viewing high spatial frequency houses, linked to the N170 component. Greater activity in this component was associated with lower attractiveness ratings of faces.ConclusionsResults provide preliminary evidence of similar abnormal spatiotemporal activation in AN and BDD for configural/holistic information for appearance- and non-appearance-related stimuli. This suggests a common phenotype of abnormal early visual system functioning, which may contribute to perceptual distortions.

Equal Degrees of Object Selectivity for Upper and Lower Visual Field Stimuli

2010 ◽  
Vol 104 (4) ◽  
pp. 2075-2081 ◽  
Author(s):  
Lars Strother ◽  
Adrian Aldcroft ◽  
Cheryl Lavell ◽  
Tutis Vilis
Keyword(s):  
Visual Field ◽  
Occipital Cortex ◽  
Recognition System ◽  
Blood Oxygen Level Dependent ◽  
Lower Visual Field ◽  
Blood Oxygen Level ◽  
Visual Areas ◽  
Bold Responses ◽  
Cortical Regions ◽  
Lateral Occipital Cortex

Functional MRI (fMRI) studies of the human object recognition system commonly identify object-selective cortical regions by comparing blood oxygen level–dependent (BOLD) responses to objects versus those to scrambled objects. Object selectivity distinguishes human lateral occipital cortex (LO) from earlier visual areas. Recent studies suggest that, in addition to being object selective, LO is retinotopically organized; LO represents both object and location information. Although LO responses to objects have been shown to depend on location, it is not known whether responses to scrambled objects vary similarly. This is important because it would suggest that the degree of object selectivity in LO does not vary with retinal stimulus position. We used a conventional functional localizer to identify human visual area LO by comparing BOLD responses to objects versus scrambled objects presented to either the upper (UVF) or lower (LVF) visual field. In agreement with recent findings, we found evidence of position-dependent responses to objects. However, we observed the same degree of position dependence for scrambled objects and thus object selectivity did not differ for UVF and LVF stimuli. We conclude that, in terms of BOLD response, LO discriminates objects from non-objects equally well in either visual field location, despite stronger responses to objects in the LVF.

scholarly journals Neural correlates of the LSD experience revealed by multimodal neuroimaging

2016 ◽  
Vol 113 (17) ◽  
pp. 4853-4858 ◽  
Author(s):  
Robin L. Carhart-Harris ◽  
Suresh Muthukumaraswamy ◽  
Leor Roseman ◽  
Mendel Kaelen ◽  
Wouter Droog ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Brain Activity ◽  
Blood Oxygen Level Dependent ◽  
Retrosplenial Cortex ◽  
Alpha Power ◽  
Blood Oxygen Level ◽  
Psychedelic Drugs ◽  
Cortex Cérébral ◽  
Intrinsic Brain Activity

Lysergic acid diethylamide (LSD) is the prototypical psychedelic drug, but its effects on the human brain have never been studied before with modern neuroimaging. Here, three complementary neuroimaging techniques: arterial spin labeling (ASL), blood oxygen level-dependent (BOLD) measures, and magnetoencephalography (MEG), implemented during resting state conditions, revealed marked changes in brain activity after LSD that correlated strongly with its characteristic psychological effects. Increased visual cortex cerebral blood flow (CBF), decreased visual cortex alpha power, and a greatly expanded primary visual cortex (V1) functional connectivity profile correlated strongly with ratings of visual hallucinations, implying that intrinsic brain activity exerts greater influence on visual processing in the psychedelic state, thereby defining its hallucinatory quality. LSD’s marked effects on the visual cortex did not significantly correlate with the drug’s other characteristic effects on consciousness, however. Rather, decreased connectivity between the parahippocampus and retrosplenial cortex (RSC) correlated strongly with ratings of “ego-dissolution” and “altered meaning,” implying the importance of this particular circuit for the maintenance of “self” or “ego” and its processing of “meaning.” Strong relationships were also found between the different imaging metrics, enabling firmer inferences to be made about their functional significance. This uniquely comprehensive examination of the LSD state represents an important advance in scientific research with psychedelic drugs at a time of growing interest in their scientific and therapeutic value. The present results contribute important new insights into the characteristic hallucinatory and consciousness-altering properties of psychedelics that inform on how they can model certain pathological states and potentially treat others.

Sounds prevent selective monitoring of high spatial frequency channels in vision

2012 ◽  
Vol 25 (0) ◽  
pp. 40
Author(s):  
Alexis Pérez-Bellido ◽  
Joan López-Moliner ◽  
Salvador Soto-Faraco
Keyword(s):  
Standard Deviation ◽  
Spatial Frequency ◽  
Visual Processing ◽  
Reaction Times ◽  
High Spatial Frequency ◽  
Visual Signals ◽  
Sensory Interactions ◽  
Multisensory Interactions ◽  
Visual Targets ◽  
Selective Monitoring

Prior knowledge about the spatial frequency (SF) of upcoming visual targets (Gabor patches) speeds up average reaction times and decreases standard deviation. This has often been regarded as evidence for a multichannel processing of SF in vision. Multisensory research, on the other hand, has often reported the existence of sensory interactions between auditory and visual signals. These interactions result in enhancements in visual processing, leading to lower sensory thresholds and/or more precise visual estimates. However, little is known about how multisensory interactions may affect the uncertainty regarding visual SF. We conducted a reaction time study in which we manipulated the uncertanty about SF (SF was blocked or interleaved across trials) of visual targets, and compared visual only versus audio–visual presentations. Surprisingly, the analysis of the reaction times and their standard deviation revealed an impairment of the selective monitoring of the SF channel by the presence of a concurrent sound. Moreover, this impairment was especially pronounced when the relevant channels were high SFs at high visual contrasts. We propose that an accessory sound automatically favours visual processing of low SFs through the magnocellular channels, thereby detracting from the potential benefits from tuning into high SF psychophysical-channels.

Increased regional homogeneity of blood oxygen level-dependent signals in occipital cortex of early blind individuals

Neuroreport ◽  
2011 ◽  
Vol 22 (4) ◽  
pp. 190-194 ◽  
Author(s):  
Chong Liu ◽  
Yong Liu ◽  
Weilan Li ◽  
Dawei Wang ◽  
Tianzi Jiang ◽  
...  
Keyword(s):  
Occipital Cortex ◽  
Blood Oxygen Level Dependent ◽  
Regional Homogeneity ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Blood Oxygen Level ◽  
Blind Individuals

scholarly journals Disrupted parahippocampal and midbrain function underlie slower verbal learning in adolescent-onset regular cannabis use

2019 ◽  
Author(s):  
Grace Blest-Hopley ◽  
Aisling O’Neill ◽  
Robin Wilson ◽  
Vincent Giampietro ◽  
Sagnik Bhattacharyya
Keyword(s):  
Verbal Learning ◽  
Learning Task ◽  
Blood Oxygen Level Dependent ◽  
Progressive Increase ◽  
Cannabis Use ◽  
Parahippocampal Gyrus ◽  
Blood Oxygen Level ◽  
Verbal Stimuli ◽  
Eta Squared ◽  
Neural Underpinnings

Abstract Rationale Prolonged use of cannabis, the most widely used illicit drug worldwide, has been consistently associated with impairment in memory and verbal learning. Although the neurophysiological underpinnings of these impairments have been investigated previously using functional magnetic resonance imaging (fMRI), while performing memory tasks, the results of these studies have been inconsistent and no clear picture has emerged yet. Furthermore, no previous studies have investigated trial-by-trial learning. Objectives We aimed to investigate the neural underpinnings of impaired verbal learning in cannabis users as estimated over repeated learning trials. Methods We studied 21 adolescent-onset regular cannabis users and 21 non-users using fMRI performed at least 12 h after last cannabis use, while they performed a paired associate verbal learning task that allowed us to examine trial-by-trial learning. Brain activation during repeated verbal encoding and recall conditions of the task was indexed using the blood oxygen level-dependent haemodynamic response fMRI signal. Results There was a significant improvement in recall score over repeated trials indicating learning occurring across the two groups of participants. However, learning was significantly slower in cannabis users compared to non-users (p = 0.032, partial eta-squared = 0.108). While learning verbal stimuli over repeated encoding blocks, non-users displayed progressive increase in recruitment of the midbrain, parahippocampal gyrus and thalamus (p = 0.00939, partial eta-squared = 0.180). In contrast, cannabis users displayed a greater but disrupted activation pattern in these regions, which showed a stronger correlation with new word-pairs learnt over the same blocks in cannabis users than in non-users. Conclusions These results suggest that disrupted medial temporal and midbrain function underlie slower learning in adolescent-onset cannabis users.

scholarly journals Changes in Cortical Activity in Stroke Survivors Undergoing Botulinum Neurotoxin Therapy for Treatment of Focal Spasticity

2021 ◽  
Vol 2 ◽  
Author(s):  
Kaleb Vinehout ◽  
Kelsey Tynes ◽  
Miguel R. Sotelo ◽  
Allison S. Hyngstrom ◽  
John R. McGuire ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Botulinum Neurotoxin ◽  
Botulinum Toxin A ◽  
Block Design ◽  
Premotor Cortex ◽  
Motor Impairment ◽  
Brain Activation ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen Level ◽  
Finger Flexion

Background: Botulinum NeuroToxin-A (BoNT-A) relieves muscle spasticity and increases range of motion necessary for stroke rehabilitation. Determining the effects of BoNT-A therapy on brain neuroplasticity could help physicians customize its use and predict its outcome.Objective: The purpose of this study was to investigate the effects of Botulinum Toxin-A therapy for treatment of focal spasticity on brain activation and functional connectivity.Design: We used functional Magnetic Resonance Imaging (fMRI) to track changes in blood oxygen-level dependent (BOLD) activation and functional connectivity associated with BoNT-A therapy in nine chronic stroke participants, and eight age-matched controls. Scans were acquired before BoNT-A injections (W0) and 6 weeks after the injections (W6). The task fMRI scan consisted of a block design of alternating mass finger flexion and extension. The voxel-level changes in BOLD activation, and pairwise changes in functional connectivity were analyzed for BoNT-A treatment (stroke W0 vs. W6).Results: BoNT-A injection therapy resulted in significant increases in brain activation in the contralesional premotor cortex, cingulate gyrus, thalamus, superior cerebellum, and in the ipsilesional sensory integration area. Lastly, cerebellar connectivity correlated with the Fugl-Meyer assessment of motor impairment before injection, while premotor connectivity correlated with the Fugl-Meyer score after injection.Conclusion: BoNT-A therapy for treatment of focal spasticity resulted in increased brain activation in areas associated with motor control, and cerebellar connectivity correlated with motor impairment before injection. These results suggest that neuroplastic effects might take place in response to improvements in focal spasticity.

Spatial Frequency Tolerant Visual Object Representations in the Human Ventral and Dorsal Visual Processing Pathways

2019 ◽  
Vol 31 (1) ◽  
pp. 49-63 ◽  
Author(s):  
Maryam Vaziri-Pashkam ◽  
JohnMark Taylor ◽  
Yaoda Xu
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Spatial Scales ◽  
High Spatial Frequency ◽  
Visual Input ◽  
Differential Sensitivity ◽  
Visual Object ◽  
Object Representations ◽  
Object Category ◽  
Object Categories

Primate ventral and dorsal visual pathways both contain visual object representations. Dorsal regions receive more input from magnocellular system while ventral regions receive inputs from both magnocellular and parvocellular systems. Due to potential differences in the spatial sensitivites of manocellular and parvocellular systems, object representations in ventral and dorsal regions may differ in how they represent visual input from different spatial scales. To test this prediction, we asked observers to view blocks of images from six object categories, shown in full spectrum, high spatial frequency (SF), or low SF. We found robust object category decoding in all SF conditions as well as SF decoding in nearly all the early visual, ventral, and dorsal regions examined. Cross-SF decoding further revealed that object category representations in all regions exhibited substantial tolerance across the SF components. No difference between ventral and dorsal regions was found in their preference for the different SF components. Further comparisons revealed that, whereas differences in the SF component separated object category representations in early visual areas, such a separation was much smaller in downstream ventral and dorsal regions. In those regions, variations among the object categories played a more significant role in shaping the visual representational structures. Our findings show that ventral and dorsal regions are similar in how they represent visual input from different spatial scales and argue against a dissociation of these regions based on differential sensitivity to different SFs.

scholarly journals Topological inference from spontaneous activity structures in FMRI videos with peristence barcodes

2019 ◽  
Author(s):  
Arjuna P.H. Don ◽  
James F. Peters ◽  
Sheela Ramanna ◽  
Arturo Tozzi
Keyword(s):  
Betti Numbers ◽  
Brain Activation ◽  
Blood Oxygen Level Dependent ◽  
Functional Magnetic Resonance ◽  
Blood Oxygen Level ◽  
Activation Patterns ◽  
Video Frames ◽  
Natural Outcome ◽  
Spatio Temporal ◽  
Topology Of Data

AbstractSpatio-temporal brain activities with variable delay detectable in resting-state functional magnetic resonance imaging (rs-fMRI) give rise to highly reproducible structures, termed cortical lag threads, that can propagate from one brain region to another. Using a computational topology of data approach, we found that Betti numbers that are cycle counts and the areas of vortex cycles covering brain activation regions in triangulated rs-fMRI video frames make it possible to track persistent, recurring blood oxygen level dependent (BOLD) signals. Our findings have been codified and visualized in what are known as persistent barcodes. Importantly, a topology of data offers a practical approach in coping with and sidestepping massive noise in neuro data, such as unwanted dark (low intensity) regions in the neighbourhood of non-zero BOLD signals. A natural outcome of a topology of data approach is the tracking of persistent, non-trivial BOLD signals that appear intermittently in a sequence of rs-fMRI video frames. The end result of this tracking of changing lag structures is a persistent barcode, which is a pictograph that offers a convenient visual means of exhibiting, comparing and classifying brain activation patterns.

Spatial Working Memory Impairment in Patients with Non-neuropsychiatric Systemic Lupus Erythematosus: A Blood-oxygen-level Dependent Functional Magnetic Resonance Imaging Study

2017 ◽  
Vol 44 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Chun-Min Zhu ◽  
Ye Ma ◽  
Lei Xie ◽  
Jin-Zhuang Huang ◽  
Zong-Bo Sun ◽  
...  
Keyword(s):  
Cognitive Dysfunction ◽  
Lupus Erythematosus ◽  
Disease Duration ◽  
Parietal Lobe ◽  
Spatial Working Memory ◽  
Blood Oxygen Level Dependent ◽  
Parahippocampal Gyrus ◽  
Control Group ◽  
Blood Oxygen Level ◽  
Back Task

Objective.Using ethology and functional magnetic resonance imaging (fMRI) to explore mild cognitive dysfunction and spatial working memory (WM) impairment in patients with systemic lupus erythematosus (SLE) without overt neuropsychiatric symptoms (non-NPSLE) and to study whether any clinical biomarkers could serve as predictors of brain dysfunction in this disease.Methods.Eighteen non-NPSLE patients and 18 matched subjects were all tested using the Montreal cognitive assessment scale test and scanned using blood-oxygen-level dependent fMRI while performing the n-back task to investigate the activation intensity of some cognition-related areas.Results.Ethology results showed that non-NPSLE patients had mild cognitive dysfunction and memory dysfunction (p < 0.05). The fMRI scan confirmed a neural network consisting of bilateral dorsolateral prefrontal cortex (DLPFC), premotor area, parietal lobe, and supplementary motor area (SMA)/anterior cingulate cortex (ACC) that was activated during the n-back task, with right hemisphere dominance. However, only the right SMA/ACC showed a load effect in the non-NPSLE group; the activation intensity of most WM-related brain areas for the non-NPSLE group was lower than for the control group under 3 memory loads. Further, we found that the activation intensity of some cognition-related areas, including the bilateral caudate nucleus/insula and hippocampus/parahippocampal gyrus were lower than the control group under the memory loads. An inverse correlation existed between individual activation intensity and disease duration.Conclusion.Non-NPSLE–related brain damage with right DLPFC-posterior parietal lobe and parahippocampal gyrus default network causes impairment of spatial WM and mild cognitive dysfunction. Patients with longer disease duration would be expected to exhibit increased central nervous system damage.

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