scholarly journals Words and Faces on Left and Right: Perceptual Asymmetries as a Marker for SSRI Responsiveness

2021 ◽  
Author(s):  
◽  
Amy Walsh
Keyword(s):  
Right Hemisphere ◽  
Relative Advantage ◽  
Hemispheric Differences ◽  
Hemispheric Asymmetries ◽  
Emotional Words ◽  
Depressed Group ◽  
Frontal Activity ◽  
Left And Right ◽  
Eeg Recordings ◽  
Ssri Medication

<p>Vulnerability to depression has been associated with greater relative right hemisphere frontal activity, as measured by EEG recordings of alpha activity. However, there is much heterogeneity in the patterns of hemispheric asymmetries in people at risk for depression. These different patterns of hemispheric asymmetries may be related to whether an individual responds to Selective Serotonin Reuptake Inhibitor (SSRI) medication. Response to SSRIs is associated with a pattern of overall relative LH activity, whereas non-response to SSRIs is associated with a pattern of overall relative RH activity. Very little is known about how these asymmetries in neural activity relate to asymmetries in cognition. The current study investigated hemispheric differences in the processing of emotional faces and words, in individuals not vulnerable to depression (a Never Depressed group) and in individuals vulnerable to depression (a Previously Depressed group). In the chimeric faces task, the Previously Depressed group had a significantly larger left hemispatial bias compared to the Never Depressed group. This may reflect relatively greater posterior RH activity/arousal in the Previously Depressed group. No differences were found between SSRI Responders and Non-responders in the chimeric faces task. In the divided visual field task, hemispheric differences in the processing of emotional words were found between the SSRI Responders and SSRI Non-responders. In contrast to SSRI Responders and Never Depressed controls, SSRI Non-responders showed a relative advantage for negative over positive words when they were presented to their LVF/RH; and an advantage for negative words presented to their LVF/RH compared to their RVF/LH. Additionally, they were more sensitive to perceiving the valence of a word that was presented to their LVF/RH. This suggests that their RH semantic systems may differ from that of SSRI Responders and Never Depressed controls. Genetic, hormonal and cognitive factors are discussed in relation to these patterns of hemispheric asymmetries and responsiveness to SSRI medication.</p>

scholarly journals Words and Faces on Left and Right: Perceptual Asymmetries as a Marker for SSRI Responsiveness

2021 ◽  
Author(s):  
◽  
Amy Walsh
Keyword(s):  
Right Hemisphere ◽  
Relative Advantage ◽  
Hemispheric Differences ◽  
Hemispheric Asymmetries ◽  
Emotional Words ◽  
Depressed Group ◽  
Frontal Activity ◽  
Left And Right ◽  
Eeg Recordings ◽  
Ssri Medication

<p>Vulnerability to depression has been associated with greater relative right hemisphere frontal activity, as measured by EEG recordings of alpha activity. However, there is much heterogeneity in the patterns of hemispheric asymmetries in people at risk for depression. These different patterns of hemispheric asymmetries may be related to whether an individual responds to Selective Serotonin Reuptake Inhibitor (SSRI) medication. Response to SSRIs is associated with a pattern of overall relative LH activity, whereas non-response to SSRIs is associated with a pattern of overall relative RH activity. Very little is known about how these asymmetries in neural activity relate to asymmetries in cognition. The current study investigated hemispheric differences in the processing of emotional faces and words, in individuals not vulnerable to depression (a Never Depressed group) and in individuals vulnerable to depression (a Previously Depressed group). In the chimeric faces task, the Previously Depressed group had a significantly larger left hemispatial bias compared to the Never Depressed group. This may reflect relatively greater posterior RH activity/arousal in the Previously Depressed group. No differences were found between SSRI Responders and Non-responders in the chimeric faces task. In the divided visual field task, hemispheric differences in the processing of emotional words were found between the SSRI Responders and SSRI Non-responders. In contrast to SSRI Responders and Never Depressed controls, SSRI Non-responders showed a relative advantage for negative over positive words when they were presented to their LVF/RH; and an advantage for negative words presented to their LVF/RH compared to their RVF/LH. Additionally, they were more sensitive to perceiving the valence of a word that was presented to their LVF/RH. This suggests that their RH semantic systems may differ from that of SSRI Responders and Never Depressed controls. Genetic, hormonal and cognitive factors are discussed in relation to these patterns of hemispheric asymmetries and responsiveness to SSRI medication.</p>

scholarly journals Resting EEG Asymmetry Markers of Multiple Facets of the Behavioral Approach System: A LORETA Analysis

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1794
Author(s):  
Vilfredo De Pascalis ◽  
Giuliana Cirillo ◽  
Arianna Vecchio
Keyword(s):  
Frontal Lobes ◽  
Behavioral Approach ◽  
Middle Temporal Gyrus ◽  
Beta Activity ◽  
Behavioral Approach System ◽  
Superior Frontal Gyrus ◽  
Middle Temporal ◽  
Frontal Activity ◽  
Left And Right ◽  
Eeg Recordings

Previously published models of frontal activity linked high relative left frontal activity to the behavioral approach system (BAS) and impulsivity. Additionally, these models did not account for BAS facets encompassing the anticipation of reward, i.e., goal-driven persistence (BAS–GDP) and reward interest (BAS–RI), from those that deal with the actual hedonic experience of reward, i.e., reward reactivity (BAS–RR) and impulsivity (BAS–I). Using resting electroencephalographic (EEG) recordings, the source localization (LORETA) method allowed us to calculate the hemispheric asymmetry of the current density within the alpha band (7.5–13 Hz) in ten regions of interest. Compared to low BAS subtrait scorers, high BAS subtrait scorers (except for BAS–I) were correlated with greater relative left-sided activity in the superior frontal gyrus (BA10). Further, an isolated effective coherence (iCOH) analysis of the beta activity (21 Hz) disclosed that high impulsive scorers as compared to low impulsive ones had higher connectivity between the superior frontal gyrus and middle temporal gyrus, which was not compensated for by enhanced inhibitory alpha (11 Hz) connectivity between these regions. For the beta frequency, we also found in highly impulsive individuals that (i) both left and right middle temporal lobes directly influenced the activity of the left and right superior frontal lobes, and (ii) a clear decoupling between left and right superior frontal lobes. These findings could indicate reduced control by the supervisory system in more impulsive individuals.

scholarly journals The rodent hippocampus as a bilateral structure: A review of hemispheric lateralization

2017 ◽  
Author(s):  
Jake T. Jordan
Keyword(s):  
Brain Region ◽  
Spatial Information ◽  
Right Hemisphere ◽  
Neural Substrates ◽  
Hemispheric Lateralization ◽  
Hemispheric Differences ◽  
Functional Lateralization ◽  
Left And Right ◽  
The Right ◽  
Behavior And Cognition

AbstractThe left and right rodent hippocampi exhibit striking lateralization in some of the very neural substrates considered to be critical for hippocampal cognitive function. Despite this, there is an overwhelming lack of consideration for hemispheric differences in studies of the rodent hippocampus. Asymmetries identified so far suggest that a bilateral model of the hippocampus will be essential for an understanding of this brain region, and perhaps of the brain more widely. Although hypotheses have been proposed to explain how the left and right hippocampi contribute to behavior and cognition, these hypotheses have either been refuted by more recent studies or have been limited in the scope of data they explain. Here, I will first review data on human and rodent hippocampal lateralization. The implications of these data suggest that considering the hippocampus as a bilateral structure with functional lateralization will be critical moving forward in understanding the function and mechanisms of this brain region. In exploring these implications, I will then propose a hypothesis of the hippocampus as a bilateral structure. This discrete-continuous (DC) hypothesis proposes that the left and right hippocampi contribute to spatial memory and navigation in a complementary manner. Specifically, the left hemisphere stores spatial information as discrete, salient locations and that the right hemisphere represents space continuously, contributing to route computation and flexible spatial navigation. Consideration of hippocampal lateralization in designing future studies may provide insight into the function of the hippocampus and resolve debates concerning its function.

Semantic Networks in the Divided Cerebral Hemispheres

1995 ◽  
Vol 6 (4) ◽  
pp. 212-218 ◽  
Author(s):  
Alice Cronin-Golomb
Keyword(s):  
Right Hemisphere ◽  
Semantic Networks ◽  
Size Composition ◽  
Strongly Correlated ◽  
Hemispheric Differences ◽  
Semantic Organization ◽  
Left And Right ◽  
The Right ◽  
Or Organization ◽  
Visual Hemifields

Hemispheric differences in the recognition and manipulation of meaning may be based on distinctions in size, composition, or organization of the right and left semantic networks The present study describes these features of pictorially based semantic networks in 3 subjects with complete forebrain commissurotomy Stimuli were presented for prolonged viewing to the left and right visual hemifields For each trial, the subjects chose from a 20-choice array all pictures that were associated with a target, then indicated the member of each pair of chosen associates that was more closely related to the target The hemispheres' networks were found to be of similar size and composition, but were organized differently The right hemisphere more often produced linear rankings of semantic associates to a target than did the left, and rankings by the two hemispheres were not strongly correlated Hemispheric differences in semantic organization mirror differences in perceptual organization, with the right hemisphere specialized for conventional meaning and the left hemisphere specialized for detecting and processing deviations from standard meaning

Selective Attention to Faces in a Rapid Visual Stream: Hemispheric Differences in Enhancement and Suppression of Category-selective Neural Activity

2018 ◽  
Vol 30 (3) ◽  
pp. 393-410 ◽  
Author(s):  
Genevieve Quek ◽  
Dan Nemrodov ◽  
Bruno Rossion ◽  
Joan Liu-Shuang
Keyword(s):  
Selective Attention ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Hemispheric Differences ◽  
Face Categorization ◽  
The Face ◽  
Left And Right ◽  
The Right ◽  
The Impact ◽  
Selective Activity

In daily life, efficient perceptual categorization of faces occurs in dynamic and highly complex visual environments. Yet the role of selective attention in guiding face categorization has predominantly been studied under sparse and static viewing conditions, with little focus on disentangling the impact of attentional enhancement and suppression. Here we show that attentional enhancement and suppression exert a differential impact on face categorization supported by the left and right hemispheres. We recorded 128-channel EEG while participants viewed a 6-Hz stream of object images (buildings, animals, objects, etc.) with a face image embedded as every fifth image (i.e., OOOOFOOOOFOOOOF…). We isolated face-selective activity by measuring the response at the face presentation frequency (i.e., 6 Hz/5 = 1.2 Hz) under three conditions: Attend Faces, in which participants monitored the sequence for instances of female faces; Attend Objects, in which they responded to instances of guitars; and Baseline, in which they performed an orthogonal task on the central fixation cross. During the orthogonal task, face-specific activity was predominantly centered over the right occipitotemporal region. Actively attending to faces enhanced face-selective activity much more evidently in the left hemisphere than in the right, whereas attending to objects suppressed the face-selective response in both hemispheres to a comparable extent. In addition, the time courses of attentional enhancement and suppression did not overlap. These results suggest the left and right hemispheres support face-selective processing in distinct ways—where the right hemisphere is mandatorily engaged by faces and the left hemisphere is more flexibly recruited to serve current tasks demands.

Performance of long-stay schizophrenics on matched verbal and visuospatial recall tasks

1991 ◽  
Vol 21 (3) ◽  
pp. 655-660 ◽  
Author(s):  
Avraham Calev ◽  
Sanda Edelist ◽  
Sol Kugelmass ◽  
Bernard Lerer
Keyword(s):  
Right Hemisphere ◽  
Recall Task ◽  
Verbal Task ◽  
Hemispheric Differences ◽  
Verbal Mediation ◽  
Discriminating Power ◽  
Left And Right ◽  
Differential Deficit

SYNOPSISA verbal and a visuospatial recall task were compared for discriminating power, using the matched-tasks methodology. These tasks were administered to long-hospitalized schizophrenics. No evidence of a differential deficit, that is, better recall of either the verbal or the visuospatial materials, emerged in the patients. The results replicate a former finding showing no difference between verbal and visuospatial recall in schizophrenics, using memory tasks which were less sensitive as left- and right-hemisphere measures and a non-verbal task less affected by verbal mediation. This replication questions the assumption that the hemispheric differences observed in schizophrenics affect such memory tasks.

The Magnitude Representation of Small and Large Symbolic Numbers in the Left and Right Hemisphere: An Event-related fMRI Study

2011 ◽  
Vol 23 (3) ◽  
pp. 622-630 ◽  
Author(s):  
Karolien Notebaert ◽  
Sabine Nelis ◽  
Bert Reynvoet
Keyword(s):  
Parietal Cortex ◽  
Right Hemisphere ◽  
Hemispheric Differences ◽  
Activation Patterns ◽  
Magnitude Representation ◽  
Large Numbers ◽  
Fmri Study ◽  
Left And Right ◽  
Left Parietal Cortex ◽  
Fmri Adaptation

Numbers are known to be processed along the left and right intraparietal sulcus. The present study investigated hemispheric differences between the magnitude representation of small and large symbolic numbers. To this purpose, an fMRI adaptation paradigm was used, where the continuous presentation of a habituation number was interrupted by an occasional deviant number. The results presented a distance-dependent increase of activation: larger ratios of habituation and deviant number caused a larger recovery of activation. Similar activation patterns were observed for small and large symbolic numbers, which is in line with the idea of a more coarse magnitude representation for large numbers. Interestingly, this pattern of activation was only observed in the left parietal cortex, supporting the recently proposed idea of Ansari [Ansari, D. Does the parietal cortex distinguish between “10”, “Ten,” and Ten Dots? Neuron, 53, 165–167, 2007] that the left parietal cortex is specialized in the processing of encultured symbolically presented numbers.

scholarly journals Is it left or is it right? A classification approach for investigating hemispheric differences in low and high dimensionality

2021 ◽  
Author(s):  
Patrick Friedrich ◽  
Kaustubh R. Patil ◽  
Lisa N. Mochalski ◽  
Xuan Li ◽  
Julia A. Camilleri ◽  
...  
Keyword(s):  
Feature Selection ◽  
Right Hemisphere ◽  
Dimensional Space ◽  
High Dimensional ◽  
Hemispheric Differences ◽  
Dimensional Representation ◽  
Left And Right ◽  
Low Dimensional ◽  
The Right ◽  
And Function

AbstractHemispheric asymmetries, i.e., differences between the two halves of the brain, have extensively been studied with respect to both structure and function. Commonly employed pairwise comparisons between left and right are suitable for finding differences between the hemispheres, but they come with several caveats when assessing multiple asymmetries. What is more, they are not designed for identifying the characterizing features of each hemisphere. Here, we present a novel data-driven framework—based on machine learning-based classification—for identifying the characterizing features that underlie hemispheric differences. Using voxel-based morphometry data from two different samples (n = 226, n = 216), we separated the hemispheres along the midline and used two different pipelines: First, for investigating global differences, we embedded the hemispheres into a two-dimensional space and applied a classifier to assess if the hemispheres are distinguishable in their low-dimensional representation. Second, to investigate which voxels show systematic hemispheric differences, we employed two classification approaches promoting feature selection in high dimensions. The two hemispheres were accurately classifiable in both their low-dimensional (accuracies: dataset 1 = 0.838; dataset 2 = 0.850) and high-dimensional (accuracies: dataset 1 = 0.966; dataset 2 = 0.959) representations. In low dimensions, classification of the right hemisphere showed higher precision (dataset 1 = 0.862; dataset 2 = 0.894) compared to the left hemisphere (dataset 1 = 0.818; dataset 2 = 0.816). A feature selection algorithm in the high-dimensional analysis identified voxels that most contribute to accurate classification. In addition, the map of contributing voxels showed a better overlap with moderate to highly lateralized voxels, whereas conventional t test with threshold-free cluster enhancement best resembled the LQ map at lower thresholds. Both the low- and high-dimensional classifiers were capable of identifying the hemispheres in subsamples of the datasets, such as males, females, right-handed, or non-right-handed participants. Our study indicates that hemisphere classification is capable of identifying the hemisphere in their low- and high-dimensional representation as well as delineating brain asymmetries. The concept of hemisphere classifiability thus allows a change in perspective, from asking what differs between the hemispheres towards focusing on the features needed to identify the left and right hemispheres. Taking this perspective on hemispheric differences may contribute to our understanding of what makes each hemisphere special.

Individual Differences and Hemispheric Asymmetry While Processing Emotional Words

2014 ◽  
Vol 35 (3) ◽  
pp. 137-143 ◽  
Author(s):  
Lindsay M. Niccolai ◽  
Thomas Holtgraves
Keyword(s):  
Individual Differences ◽  
Hemispheric Asymmetry ◽  
Past Research ◽  
Decision Task ◽  
Depression And Anxiety ◽  
Hemispheric Differences ◽  
Affective Valence ◽  
Emotional Words ◽  
Emotion Words ◽  
The Right

This research examined differences in the perception of emotion words as a function of individual differences in subclinical levels of depression and anxiety. Participants completed measures of depression and anxiety and performed a lexical decision task for words varying in affective valence (but equated for arousal) that were presented briefly to the right or left visual field. Participants with a lower level of depression demonstrated hemispheric asymmetry with a bias toward words presented to the left hemisphere, but participants with a higher level of depression displayed no hemispheric differences. Participants with a lower level of depression also demonstrated a bias toward positive words, a pattern that did not occur for participants with a higher level of depression. A similar pattern occurred for anxiety. Overall, this study demonstrates how variability in levels of depression and anxiety can influence the perception of emotion words, with patterns that are consistent with past research.

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