scholarly journals Bilateral versus ipsilesional cortico-subcortical activity patterns in stroke show hemispheric dependence

2016 ◽  
Vol 12 (1) ◽  
pp. 71-83 ◽  
Author(s):  
A Cristina Vidal ◽  
Paula Banca ◽  
Augusto G Pascoal ◽  
Gustavo C Santo ◽  
João Sargento-Freitas ◽  
...  
Keyword(s):  
Brain Activity ◽  
Block Design ◽  
Activity Patterns ◽  
Prognostic Indicator ◽  
Response Patterns ◽  
Stroke Patients ◽  
Activation Patterns ◽  
Hemispheric Stroke ◽  
Constraint Induced Movement Therapy ◽  
Motor Outcomes

Background Understanding of interhemispheric interactions in stroke patients during motor control is an important clinical neuroscience quest that may provide important clues for neurorehabilitation. In stroke patients, bilateral overactivation in both hemispheres has been interpreted as a poor prognostic indicator of functional recovery. In contrast, ipsilesional patterns have been linked with better motor outcomes. Aim We investigated the pathophysiology of hemispheric interactions during limb movement without and with contralateral restraint, to mimic the effects of constraint-induced movement therapy. We used neuroimaging to probe brain activity with such a movement-dependent interhemispheric modulation paradigm. Methods We used an fMRI block design during which the plegic/paretic upper limb was recruited/mobilized to perform unilateral arm elevation, as a function of presence versus absence of contralateral limb restriction ( n = 20, with balanced left/right lesion sites). Results Analysis of 10 right-hemispheric stroke participants yielded bilateral sensorimotor cortex activation in all movement phases in contrast with the unilateral dominance seen in the 10 left-hemispheric stroke participants. Superimposition of contralateral restriction led to a prominent shift from activation to deactivation response patterns, in particular in cortical and basal ganglia motor areas in right-hemispheric stroke. Left-hemispheric stroke was in general characterized by reduced activation patterns, even in the absence of restriction, which induced additional cortical silencing. Conclusion The observed hemispheric-dependent activation/deactivation shifts are novel and these pathophysiological observations suggest short-term neuroplasticity that may be useful for hemisphere-tailored neurorehabilitation.

Dissociable Neural Patterns of Facial Identity across Changes in Viewpoint

2010 ◽  
Vol 22 (7) ◽  
pp. 1570-1582 ◽  
Author(s):  
Vaidehi S. Natu ◽  
Fang Jiang ◽  
Abhijit Narvekar ◽  
Shaiyan Keshvari ◽  
Volker Blanz ◽  
...  
Keyword(s):  
Activity Patterns ◽  
Human Perception ◽  
Neural Response ◽  
Behavioral Experiment ◽  
Neural Activation ◽  
Response Patterns ◽  
Activation Patterns ◽  
Facial Identity ◽  
The Face ◽  
High Level

We examined the neural response patterns for facial identity independent of viewpoint and for viewpoint independent of identity. Neural activation patterns for identity and viewpoint were collected in an fMRI experiment. Faces appeared in identity-constant blocks, with variable viewpoint, and in viewpoint-constant blocks, with variable identity. Pattern-based classifiers were used to discriminate neural response patterns for all possible pairs of identities and viewpoints. To increase the likelihood of detecting distinct neural activation patterns for identity, we tested maximally dissimilar “face”–“antiface” pairs and normal face pairs. Neural response patterns for four of six identity pairs, including the “face”–“antiface” pairs, were discriminated at levels above chance. A behavioral experiment showed accord between perceptual and neural discrimination, indicating that the classifier tapped a high-level visual identity code. Neural activity patterns across a broad span of ventral temporal (VT) cortex, including fusiform gyrus and lateral occipital areas (LOC), were required for identity discrimination. For viewpoint, five of six viewpoint pairs were discriminated neurally. Viewpoint discrimination was most accurate with a broad span of VT cortex, but the neural and perceptual discrimination patterns differed. Less accurate discrimination of viewpoint, more consistent with human perception, was found in right posterior superior temporal sulcus, suggesting redundant viewpoint codes optimized for different functions. This study provides the first evidence that it is possible to dissociate neural activation patterns for identity and viewpoint independently.

scholarly journals Head MagnetoMyography (hMMG): a novel approach to monitor face and whole-head muscular activity

2019 ◽  
Author(s):  
Guido Barchiesi ◽  
Gianpaolo Demarchi ◽  
Frank H. Wilhelm ◽  
Anne Hauswald ◽  
Gaëtan Sanchez ◽  
...  
Keyword(s):  
Brain Activity ◽  
Activity Patterns ◽  
A Priori ◽  
Muscular Activity ◽  
Electrode Placement ◽  
Emotional Facial Expressions ◽  
Extended Body ◽  
Activation Patterns ◽  
Novel Approach ◽  
Positive Valence

AbstractMuscular activity recording is of high basic science and clinical relevance and is typically achieved using electromyography (EMG). While providing detailed information about the state of a specific muscle, this technique has limitations such as the need for a-priori assumptions about electrode placement and difficulty with recording muscular activity patterns from extended body areas at once. For head and face muscle activity, the present work aimed to overcome these restrictions by exploiting magnetoencephalography (MEG) as a whole-head myographic recorder (head magnetomyography, hMMG). This is in contrast to common MEG studies, which treat muscular activity as artifact in electromagnetic brain activity. In a first proof-of-concept step, participants imitated emotional facial expressions performed by a model. Exploiting source projection algorithms, we were able to reconstruct muscular activity, showing spatial activation patterns in accord with the hypothesized muscular contractions. Going one step further, participants passively observed affective pictures with negative, neutral, or positive valence. Applying multivariate pattern analysis to the reconstructed hMMG signal, we were able to decode above chance the valence category of the presented pictures. Underlining the potential of hMMG, a searchlight analysis revealed that generally neglected neck muscles exhibit information on stimulus valence. Results confirm the utility of hMMG as a whole-head electromyographic recorder to quantify muscular activation patterns including muscular regions that are typically not recorded with EMG. This key advantage beyond conventional EMG has substantial scientific and clinical potential.

Differences in Chemo-signaling Compound-Evoked Brain Activity in Male and Female Young Adults: A Pilot Study in the Role of Sexual Dimorphism in Olfactory Chemo-Signaling

2020 ◽  
Author(s):  
Taylor D. Ottesen ◽  
Kevin C. Davis ◽  
Landon K. Hobbs ◽  
Nathan M. Muncy ◽  
Nicholas M. Stevens ◽  
...  
Keyword(s):  
Young Adults ◽  
Pilot Study ◽  
Neural Development ◽  
Brain Activity ◽  
Block Design ◽  
Inferior Frontal Gyrus ◽  
Multivariate Model ◽  
Neural Activation ◽  
Whole Brain ◽  
Activation Patterns

AbstractIntroductionPrevious studies have shown that putative pheromones 4,16-androstadien-3-one (AND) and estra-1,3,5(10),16-tetraen-3-ol (EST) cause activation in the preoptic area/anterior hypothalamus in men and women. Sex differences in neural activation patterns have been demonstrated when participants are subject to pheromone stimulation; however, whether other compounds give rise to similar neural activity has not been completely investigated.MethodsTwenty-nine young adults [16 female (21.3+/−0.54; mean yrs+/−SE), 13 male (22.85+/−0.42)] participated in a 3-block design, where participants were exposed to a scent (lavender), a synthetic male pheromone (4,16-androstadien-3b-ol; ALD), and a synthetic female pheromone (1,3,5(10),16-Estratetraen-3-ol; EST) via an automated olfactometer. Whole-brain, high-resolution (1.8mm3) functional MRI data from a Siemens Trio 3T MRI scanner were collected during all blocks. Five adults were excluded due to excessive movement. MANOVA analysis, a 2 × 3 multivariate model and analysis of 2×2 effects between sex and subsets of stimuli was done for activation over the whole brain and small volumes involved in olfaction.ResultsExploratory analysis of 2×2 effects between sex and subsets of stimuli exhibited significant interactions when assessing activations over the whole brain, and small volumes involved in olfaction. The left and right frontal poles (LFP, RFP) shows significant interaction when assessing sex with lavender and EST for whole brain analysis. For small volume analysis, the right orbitofrontal cortex (ROFC) exhibited a sex with lavender and ALD interaction, and a sex with lavender and EST interaction was observed in the left inferior frontal gyrus (LIFG). Main effects of sex, stimulus, or interaction show no differences analyzed using a 2 × 3 multivariate model.ConclusionThe study shows there is a sexually dimorphic response in the olfactory system to pheromones not previously studied. Scents like lavender do not have this same response. These distinct functional differences in activation patterns may be a result of neural development and maturation differences between sexes. Future studies should expand this pilot study and involve a younger demographic to accurately determine the age at which the olfactory response differentiates between males and females.

scholarly journals Common neural and transcriptional correlates of inhibitory control underlie emotion regulation and memory control

2020 ◽  
Vol 15 (5) ◽  
pp. 523-536 ◽  
Author(s):  
Wei Liu ◽  
Nancy Peeters ◽  
Guillén Fernández ◽  
Nils Kohn
Keyword(s):  
Emotion Regulation ◽  
Inhibitory Control ◽  
Brain Activity ◽  
Activity Patterns ◽  
Enrichment Analysis ◽  
Brain Atlas ◽  
Activation Patterns ◽  
Memory Control ◽  
The Right ◽  
Meta Analyses

Abstract Inhibitory control is crucial for regulating emotions and may also enable memory control. However, evidence for their shared neurobiological correlates is limited. Here, we report meta-analyses of neuroimaging studies on emotion regulation, or memory control and link neural commonalities to transcriptional commonalities using the Allen Human Brain Atlas (AHBA). Based on 95 functional magnetic resonance imaging studies, we reveal a role of the right inferior parietal lobule embedded in a frontal–parietal–insular network during emotion regulation and memory control, which is similarly recruited during response inhibition. These co-activation patterns also overlap with the networks associated with ‘inhibition’, ‘cognitive control’ and ‘working memory’ when consulting the Neurosynth. Using the AHBA, we demonstrate that emotion regulation- and memory control-related brain activity patterns are associated with transcriptional profiles of a specific set of ‘inhibition-related’ genes. Gene ontology enrichment analysis of these ‘inhibition-related’ genes reveal associations with the neuronal transmission and risk for major psychiatric disorders as well as seizures and alcoholic dependence. In summary, this study identified a neural network and a set of genes associated with inhibitory control across emotion regulation and memory control. These findings facilitate our understanding of the neurobiological correlates of inhibitory control and may contribute to the development of brain stimulation and pharmacological interventions.

scholarly journals Stimulus set meaningfulness and neurophysiological differentiation: a functional magnetic resonance imaging study

2014 ◽  
Author(s):  
Melanie Boly ◽  
Shuntaro Sasai ◽  
Olivia Gosseries ◽  
Masafumi Oizumi ◽  
Adenauer Casali ◽  
...  
Keyword(s):  
Information Integration ◽  
Brain Activity ◽  
Activity Patterns ◽  
Imaging Study ◽  
Cortical Activation ◽  
Neural Responses ◽  
Activation Patterns ◽  
Stimulus Set ◽  
The Subject ◽  
Cortical Regions

A meaningful set of stimuli, such as a sequence of frames from a movie, triggers a set of different experiences. By contrast, a meaningless set of stimuli, such as a sequence of 'TV noise' frames, triggers always the same experience – of seeing 'TV noise' – even though the stimuli themselves are as different from each other as the movie frames. We reasoned that the differentiation of cortical responses underlying the subject's experiences, as measured by Lempel-Ziv complexity (incompressibility) of functional MRI images, should reflect the overall meaningfulness of a set of stimuli for the subject, rather than differences among the stimuli. We tested this hypothesis by quantifying the differentiation of brain activity patterns in response to a movie sequence, to the same movie scrambled in time, and to 'TV noise', where the pixels from each movie frame were scrambled in space. While overall cortical activation was strong and widespread in all conditions, the differentiation (Lempel-Ziv complexity) of brain activation patterns was correlated with the meaningfulness of the stimulus set, being highest in the movie condition, intermediate in the scrambled movie condition, and minimal for 'TV noise'. Stimulus set meaningfulness was also associated with higher information integration among cortical regions. These results suggest that the differentiation of neural responses can be used to assess the meaningfulness of a given set of stimuli for a given subject, without the need to identify the features and categories that are relevant to the subject, nor the precise location of selective neural responses.

scholarly journals The Neural Basis of Vivid Memory Is Patterned on Perception

2012 ◽  
Vol 24 (9) ◽  
pp. 1867-1883 ◽  
Author(s):  
Bradley R. Buchsbaum ◽  
Sabrina Lemire-Rodger ◽  
Candice Fang ◽  
Hervé Abdi
Keyword(s):  
Brain Activity ◽  
Sensory Perception ◽  
Direct Perception ◽  
Neural Basis ◽  
Activation Patterns ◽  
Short Video ◽  
Initial Perception ◽  
Experiential Quality ◽  
High Degree

When we have a rich and vivid memory for a past experience, it often feels like we are transported back in time to witness once again this event. Indeed, a perfect memory would exactly mimic the experiential quality of direct sensory perception. We used fMRI and multivoxel pattern analysis to map and quantify the similarity between patterns of activation evoked by direct perception of a diverse set of short video clips and the vivid remembering, with closed eyes, of these clips. We found that the patterns of distributed brain activation during vivid memory mimicked the patterns evoked during sensory perception. Using whole-brain patterns of activation evoked by perception of the videos, we were able to accurately classify brain patterns that were elicited when participants tried to vividly recall those same videos. A discriminant analysis of the activation patterns associated with each video revealed a high degree (explaining over 80% of the variance) of shared representational similarity between perception and memory. These results show that complex, multifeatured memory involves a partial reinstatement of the whole pattern of brain activity that is evoked during initial perception of the stimulus.

scholarly journals Neural alignment predicts learning outcomes in students taking an introduction to computer science course

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Meir Meshulam ◽  
Liat Hasenfratz ◽  
Hanna Hillman ◽  
Yun-Fei Liu ◽  
Mai Nguyen ◽  
...  
Keyword(s):  
Computer Science ◽  
Learning Outcomes ◽  
Brain Activity ◽  
Activity Patterns ◽  
Real Life ◽  
Final Exam ◽  
Neural Representations ◽  
Real Life Setting ◽  
The Right ◽  
Mri Study

AbstractDespite major advances in measuring human brain activity during and after educational experiences, it is unclear how learners internalize new content, especially in real-life and online settings. In this work, we introduce a neural approach to predicting and assessing learning outcomes in a real-life setting. Our approach hinges on the idea that successful learning involves forming the right set of neural representations, which are captured in canonical activity patterns shared across individuals. Specifically, we hypothesized that learning is mirrored in neural alignment: the degree to which an individual learner’s neural representations match those of experts, as well as those of other learners. We tested this hypothesis in a longitudinal functional MRI study that regularly scanned college students enrolled in an introduction to computer science course. We additionally scanned graduate student experts in computer science. We show that alignment among students successfully predicts overall performance in a final exam. Furthermore, within individual students, we find better learning outcomes for concepts that evoke better alignment with experts and with other students, revealing neural patterns associated with specific learned concepts in individuals.

scholarly journals Using Brain Activity Patterns to Differentiate Real and Virtual Attended Targets during Augmented Reality Scenarios

Information ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 226
Author(s):  
Lisa-Marie Vortmann ◽  
Leonid Schwenke ◽  
Felix Putze
Keyword(s):  
Augmented Reality ◽  
Eye Tracking ◽  
Brain Activity ◽  
Activity Patterns ◽  
Training Data ◽  
Machine Learning Techniques ◽  
Neural Net ◽  
Dependent Manner ◽  
Tracking Data ◽  
Average Accuracy

Augmented reality is the fusion of virtual components and our real surroundings. The simultaneous visibility of generated and natural objects often requires users to direct their selective attention to a specific target that is either real or virtual. In this study, we investigated whether this target is real or virtual by using machine learning techniques to classify electroencephalographic (EEG) and eye tracking data collected in augmented reality scenarios. A shallow convolutional neural net classified 3 second EEG data windows from 20 participants in a person-dependent manner with an average accuracy above 70% if the testing data and training data came from different trials. This accuracy could be significantly increased to 77% using a multimodal late fusion approach that included the recorded eye tracking data. Person-independent EEG classification was possible above chance level for 6 out of 20 participants. Thus, the reliability of such a brain–computer interface is high enough for it to be treated as a useful input mechanism for augmented reality applications.

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