Effects of Psychostimulants on Alertness and Spatial Bias in Healthy Participants

2009 ◽  
Vol 21 (3) ◽  
pp. 529-537 ◽  
Author(s):  
Chris Dodds ◽  
Ulrich Müller ◽  
Tom Manly
Keyword(s):  
Spatial Attention ◽  
Right Hemisphere ◽  
Time On Task ◽  
Spatial Bias ◽  
Placebo Condition ◽  
Functional Link ◽  
Cortical Areas ◽  
Time Interaction ◽  
Lateral Bias ◽  
Healthy Participants

Converging evidence from neuropsychological and neuroimaging studies suggests that the ability to maintain an alert, ready-to-respond state is mediated by a network of right-hemisphere frontal and parietal cortical areas. This right lateralization may help to explain why visuospatial hemineglect, a cluster of deficits in detecting and responding to contralesional stimuli, is more common and persistent after right-hemisphere lesions. Indeed, it has been hypothesized that this asymmetry reflects a direct, functional link between alertness and spatial attention. In the present study, we investigated whether a pharmacologically induced increase in alertness would influence lateral bias in healthy people. Eighteen healthy participants were each given placebo or the psychostimulant drugs methylphenidate 40 mg or modafinil 400 mg on separate days and completed an hour-long version of the spatially sensitive landmark task. For those participants who demonstrated the expected alerting effect of modafinil, there was a significant Condition by Time interaction, consistent with the effects of the drug resisting time-on-task rightward drifts in spatial bias in the placebo condition. In contrast, no effect of methylphenidate on spatial bias was observed. These results suggest that spatial bias may be modulated by a psychostimulant-induced increase in alertness, supporting the hypothesis of a direct, functional link between right-hemisphere systems controlling alertness and visuospatial attention.

scholarly journals The Right Hemisphere Is Responsible for the Greatest Differences in Human Brain Response to High-Arousing Emotional versus Neutral Stimuli: A MEG Study

2021 ◽  
Vol 11 (8) ◽  
pp. 960
Author(s):  
Mina Kheirkhah ◽  
Philipp Baumbach ◽  
Lutz Leistritz ◽  
Otto W. Witte ◽  
Martin Walter ◽  
...  
Keyword(s):  
Human Brain ◽  
Right Hemisphere ◽  
Emotional Stimuli ◽  
Brain Response ◽  
Whole Brain ◽  
Brain Responses ◽  
Cortical Regions ◽  
The Right ◽  
Healthy Participants

Studies investigating human brain response to emotional stimuli—particularly high-arousing versus neutral stimuli—have obtained inconsistent results. The present study was the first to combine magnetoencephalography (MEG) with the bootstrapping method to examine the whole brain and identify the cortical regions involved in this differential response. Seventeen healthy participants (11 females, aged 19 to 33 years; mean age, 26.9 years) were presented with high-arousing emotional (pleasant and unpleasant) and neutral pictures, and their brain responses were measured using MEG. When random resampling bootstrapping was performed for each participant, the greatest differences between high-arousing emotional and neutral stimuli during M300 (270–320 ms) were found to occur in the right temporo-parietal region. This finding was observed in response to both pleasant and unpleasant stimuli. The results, which may be more robust than previous studies because of bootstrapping and examination of the whole brain, reinforce the essential role of the right hemisphere in emotion processing.

Age-Related Changes in the Allocation of Vertical Attention

2018 ◽  
Vol 24 (10) ◽  
pp. 1121-1124 ◽  
Author(s):  
Aleksandra Mańkowska ◽  
Kenneth M. Heilman ◽  
John B. Williamson ◽  
Michał Harciarek
Keyword(s):  
Spatial Attention ◽  
Right Hemisphere ◽  
Ventral Stream ◽  
Midsagittal Plane ◽  
Visual Stream ◽  
Leftward Bias ◽  
Healthy Elderly ◽  
Age Related ◽  
The Right ◽  
Dorsal Visual Stream

AbstractObjectives: Healthy individuals often have a leftward and upward attentional spatial bias; however, there is a reduction of this leftward bias with aging. The right hemisphere mediates leftward spatial attention and age-related reduction of right hemispheric activity may account for this reduced leftward bias. The right hemisphere also appears to be responsible for upward bias, and this upward bias might reduce with aging. Alternatively, whereas the dorsal visual stream allocates attention downward, the ventral stream allocates attention upward. Since with aging there is a greater atrophy of the dorsal than ventral stream, older participants may reveal a greater upward bias. The main purpose of this study was to learn if aging influences the vertical allocation of spatial attention. Methods: Twenty-six young (17 males; mean age 44.62±2.57 years) and 25 healthy elderly (13 males; mean age 72.04±.98 years), right-handed adults performed line bisections using 24 vertical lines (24 cm long and 2 mm thick) aligned with their midsagittal plane. Results: Older adults had a significantly greater upward bias than did younger adults. Conclusions: Normal upward attentional bias increases with aging, possibly due to an age-related reduction of the dorsal attentional stream that is responsible for the allocation of downward attention. (JINS, 2018, 24, 1121–1124)

scholarly journals Impaired cognitive self-awareness mediates the association between alexithymia and excitation/inhibition balance in the pgACC

2019 ◽  
Vol 50 (10) ◽  
pp. 1727-1735
Author(s):  
A. Kühnel ◽  
A. Widmann ◽  
L. Colic ◽  
L. Herrmann ◽  
L. R. Demenescu ◽  
...  
Keyword(s):  
Emotion Regulation ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Negative Feedback ◽  
Anterior Cingulate ◽  
Resonance Spectroscopy ◽  
Self Awareness ◽  
Cortical Areas ◽  
Cognitive Awareness ◽  
Healthy Participants

AbstractBackgroundPrevious research showed that automatic emotion regulation is associated with activation of subcortical areas and subsequent feedforward processes to cortical areas. In contrast, cognitive awareness of emotions is mediated by negative feedback from cortical to subcortical areas. Pregenual anterior cingulate cortex (pgACC) is essential in the modulation of both affect and alexithymia. We considered the interplay between these two mechanisms in the pgACC and their relationship with alexithymia.MethodIn 68 healthy participants (30 women, age = 26.15 ± 4.22) we tested associations of emotion processing and alexithymia with excitation/inhibition (E/I) balance represented as glutamate (Glu)/GABA in the pgACC measured via magnetic resonance spectroscopy in 7 T.ResultsAlexithymia was positively correlated with the Glu/GABA ratio (N = 41, p = 0.0393). Further, cognitive self-awareness showed an association with Glu/GABA (N = 52, p = 0.003), which was driven by a correlation with GABA. In contrast, emotion regulation was only correlated with glutamate levels in the pgACC (N = 49, p = 0.008).ConclusionOur results corroborate the importance of the pgACC as a mediating region of alexithymia, reflected in an altered E/I balance. Furthermore, we could specify that this altered balance is linked to a GABA-related modulation of cognitive self-awareness of emotions.

scholarly journals A unified neurocomputational bilateral model of spoken language production in healthy participants and recovery in poststroke aphasia

2020 ◽  
Vol 117 (51) ◽  
pp. 32779-32790
Author(s):  
Ya-Ning Chang ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Language Processing ◽  
Language Production ◽  
Right Hemisphere ◽  
Spoken Language ◽  
Partial Recovery ◽  
Language Performance ◽  
Unified Framework ◽  
Different Types ◽  
Formal Basis ◽  
Healthy Participants

Understanding the processes underlying normal, impaired, and recovered language performance has been a long-standing goal for cognitive and clinical neuroscience. Many verbally described hypotheses about language lateralization and recovery have been generated. However, they have not been considered within a single, unified, and implemented computational framework, and the literatures on healthy participants and patients are largely separated. These investigations also span different types of data, including behavioral results and functional MRI brain activations, which augment the challenge for any unified theory. Consequently, many key issues, apparent contradictions, and puzzles remain to be solved. We developed a neurocomputational, bilateral pathway model of spoken language production, designed to provide a unified framework to simulate different types of data from healthy participants and aphasic patients. The model encapsulates key computational principles (differential computational capacity, emergent division of labor across pathways, experience-dependent plasticity-related recovery) and provides an explanation for the bilateral yet asymmetric lateralization of language in healthy participants, chronic aphasia after left rather than right hemisphere lesions, and the basis of partial recovery in patients. The model provides a formal basis for understanding the relationship between behavioral performance and brain activation. The unified model is consistent with the degeneracy and variable neurodisplacement theories of language recovery, and adds computational insights to these hypotheses regarding the neural machinery underlying language processing and plasticity-related recovery following damage.

scholarly journals Atypical Hemispheric Dominance for Attention: Functional MRI Topography

2005 ◽  
Vol 25 (9) ◽  
pp. 1197-1208 ◽  
Author(s):  
Agnes Flöel ◽  
Andreas Jansen ◽  
Michael Deppe ◽  
Martin Kanowski ◽  
Carsten Konrad ◽  
...  
Keyword(s):  
Spatial Attention ◽  
Right Hemisphere ◽  
Regional Distribution ◽  
Visuospatial Attention ◽  
Hemispheric Dominance ◽  
Neural Activation ◽  
Brain Organization ◽  
Attention Task ◽  
Control Subjects ◽  
The Right

The right hemisphere is predominantly involved in tasks associated with spatial attention. However, left hemispheric dominance for spatial attention can be found in healthy individuals, and both spatial attention and language can be lateralized to the same hemisphere. Little is known about the underlying regional distribution of neural activation in these ‘atypical’ individuals. Previously a large number of healthy subjects were screened for hemispheric dominance of visuospatial attention and language, using functional Doppler ultrasonography. From this group, subjects were chosen who were ‘atypical’ for hemispheric dominance of visuospatial attention and language, and their pattern of brain activation was studied with functional magnetic resonance imaging during a task probing spatial attention. Right-handed subjects with the ‘typical’ pattern of brain organization served as control subjects. It was found that subjects with an inverted lateralization of language and spatial attention (language right, attention left) recruited left-hemispheric areas in the attention task, homotopic to those recruited by control subjects in the right hemisphere. Subjects with lateralization of both language and attention to the right hemisphere activated an attentional network in the right hemisphere that was comparable to control subjects. The present findings suggest that not the hemispheric side, but the intrahemispheric pattern of activation is the distinct feature for the neural processes underlying language and attention.

scholarly journals Functional localization of the frontal eye fields in the common marmoset using microstimulation

2019 ◽  
Author(s):  
Janahan Selvanayagam ◽  
Kevin D. Johnston ◽  
David J. Schaeffer ◽  
Lauren K. Hayrynen ◽  
Stefan Everling
Keyword(s):  
Spatial Attention ◽  
Common Marmoset ◽  
Frontal Eye Field ◽  
Cortical Region ◽  
Compelling Evidence ◽  
Primate Model ◽  
Promising Alternative ◽  
Cortical Areas ◽  
Eye Field ◽  
The Common

AbstractThe frontal eye field (FEF) is a critical region for the deployment of overt and covert spatial attention. While investigations in the macaque continue to provide insight into the neural underpinnings of the FEF, due to its location within a sulcus the macaque FEF is virtually inaccessible to electrophysiological techniques such as high-density and laminar recordings. With a largely lissencephalic cortex, the common marmoset (Callithrix jacchus) is a promising alternative primate model for studying FEF microcircuitry. Putative homologies have been established with the macaque FEF on the basis of cytoarchitecture and connectivity, however physiological investigation in awake, behaving marmosets is necessary to physiologically locate this area. Here we addressed this gap using intracortical microstimulation in a broad range of frontal cortical areas in marmosets. We implanted marmosets with 96-channel Utah arrays and applied microstimulation trains while they freely viewed video clips. We evoked short-latency fixed vector saccades at low currents (<50 μA) in areas 45, 8aV, 8C and 6DR. We observed a topography of saccade direction and amplitude consistent with findings in macaques and humans; we observed small saccades in ventrolateral FEF and large saccades combined with contralateral neck and shoulder movements encoded in dorsomedial FEF. Our data provide compelling evidence supporting homology between marmoset and macaque FEF and suggest the marmoset is a useful primate model for investigating FEF microcircuitry and its contributions to oculomotor and cognitive functions.Significance StatementThe frontal eye field (FEF) is a critical cortical region for overt and covert spatial attention. The microcircuitry of this area remains poorly understood, as in the macaque, the most commonly used model, it is embedded within a sulcus and is inaccessible to modern electrophysiological and optical imaging techniques. The common marmoset is a promising alternative primate model due to its lissencephalic cortex and potential for genetic manipulation. However, evidence for homologous cortical areas in this model remains limited and unclear. Here we applied microstimulation in frontal cortical areas in marmosets to physiologically identify the FEF. Our results provide compelling evidence for a frontal eye field in the marmoset, and suggest that the marmoset is a useful model for FEF microcircuitry.

scholarly journals Monotonous driving induces shifts in spatial attention as a function of handedness

2020 ◽  
Author(s):  
Dilushi Chandrakumar ◽  
Scott Coussens ◽  
Hannah AD Keage ◽  
Siobhan Banks ◽  
Jill Dorrian ◽  
...  
Keyword(s):  
Spatial Attention ◽  
Current Evidence ◽  
Time On Task ◽  
Opposite Pattern ◽  
Simulated Driving ◽  
Attention Tasks ◽  
Task Effect ◽  
Driving Task ◽  
The Right ◽  
Simulated Driving Task

Current evidence suggests that the ability to detect and react to information under lowered alertness conditions might be more impaired on the left than the right side of space. This evidence derives mainly from right-handers being assessed in computer and paper-and-pencil spatial attention tasks. However, there are suggestions that left-handers might show impairments on the opposite (right) side compared to right-handers with lowered alertness, and it is unclear whether the impairments observed in the computer tasks have any real-world implications for activities such as driving. The current study investigated the alertness and spatial attention relationship under simulated monotonous driving in left- and right-handers. Twenty left-handed and 22 right-handed participants (15 males, mean age=23.6y, SD=5.0y) were assessed on a simulated driving task (lasting approximately 60 minutes) to induce a time-on-task effect. The driving task involved responding to stimuli appearing at six different horizontal locations on the screen, whilst driving in a 50km/h zone. Decreases in alertness and driving performance were evident with time-on-task in both handedness groups. We found handedness impacts reacting to lateral stimuli differently with time-on-task: right-handers reacted slower to the leftmost stimuli, while left-handers showed the opposite pattern (although not statistically significant) in the second compared to first half of the drive. Our findings support suggestions that handedness modulates the spatial attention and alertness interactions. The interactions were observed in a simulated driving task which calls for further research to understand the safety implications of these interactions for activities such as driving.

scholarly journals Remembering a name: Neuropsychological validity studies and a computer proposal for detection of anomia

2019 ◽  
Vol 13 (4) ◽  
pp. 450-462
Author(s):  
Nora Silvana Vigliecca ◽  
Javier Alfredo Voos
Keyword(s):  
Memory Impairment ◽  
Right Hemisphere ◽  
Demographic Variables ◽  
Control Data ◽  
Environmental Interventions ◽  
Right Hemisphere Damage ◽  
Confrontation Naming ◽  
Validity Studies ◽  
Healthy Participants ◽  
Naming Test

ABSTRACT There are contradictory results or lack of validity studies concerning the naming function and brain laterality. Although anomia is a frequent symptom of memory impairment, and the most relevant symptom of aphasia, few studies have been conducted to evaluate its validity for detecting patients with left-hemisphere damage (LD), as per the MeSH definition. Objective: To validate a paper-and-pencil confrontation naming test (CNT) according to side of brain injury; to select a valid and reliable abbreviated CNT wherein the effect of demographic variables is minimized; and to use the selected CNT to develop a computer-aided confrontation-naming evaluation (CACNE). Methods: Control data were obtained from 213 healthy participants (HP) aged 15 to 89 years. A subsample of 106 HP was demographically matched to 39 patients with LD and 40 patients with right-hemisphere damage (RD). Anomia definition and CNT cues were considered for the CACNE. Results: Test-retest and inter-rater reliability, internal consistency, and validity for detecting LD were demonstrated. A significant age effect was observed in HP. The CACNE was developed to detect anomia in interaction with environmental interventions. Conclusion: The inconsistencies observed in the CNT studies were probably due to the presence of anomia in almost 50% of the RD patients.

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