scholarly journals Neural Representations of Death in the Cortical Midline Structures Promote Temporal Discounting

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Kuniaki Yanagisawa ◽  
Emiko S Kashima ◽  
Yayoi Shigemune ◽  
Ryusuke Nakai ◽  
Nobuhito Abe
Keyword(s):  
Temporal Discounting ◽  
Future Thinking ◽  
Multivoxel Pattern Analysis ◽  
Default Mode ◽  
Neural Representations ◽  
Economic Decision Making ◽  
Imaging Experiment ◽  
Behavioral Evidence ◽  
Decoding Accuracy ◽  
Magnetic Resonance Imaging Experiment

Abstract Death is an important reminder that our lives are finite. Although some studies have shown that thinking about one’s own death increases temporal discounting (i.e., the devaluing of future rewards), the underlying neural mechanisms are still unknown. In a functional magnetic resonance imaging experiment, we compared the neural and behavioral processes of temporal discounting across four conditions involving distinct types of future thinking (death related, negative, neutral, and positive). Replicating prior research, the behavioral evidence showed that temporal discounting increased when thinking about one’s own future death. Multivoxel pattern analysis showed that death-related future thinking was decoded in default mode regions, including the inferior parietal lobule, precuneus, and medial prefrontal cortex (MPFC). When future thinking was death related (vs. negative), increased temporal discounting was associated with a higher decoding accuracy in the precuneus and MPFC. The present findings suggest that death-related neural representations are distributed across default mode regions, and neural populations in the cortical midline structures play a crucial role in the integration of one's own death into economic decision-making.

Attentional Fluctuations Influence the Neural Fidelity and Connectivity of Stimulus Representations

2018 ◽  
Vol 30 (9) ◽  
pp. 1209-1228 ◽  
Author(s):  
David Rothlein ◽  
Joseph DeGutis ◽  
Michael Esterman
Keyword(s):  
Functional Connectivity ◽  
Large Scale ◽  
Brain Networks ◽  
Relevant Information ◽  
Mental States ◽  
Attention Task ◽  
Default Mode ◽  
Neural Representations ◽  
Similarity Structure ◽  
Similarity Matrices

Attention is thought to facilitate both the representation of task-relevant features and the communication of these representations across large-scale brain networks. However, attention is not “all or none,” but rather it fluctuates between stable/accurate (in-the-zone) and variable/error-prone (out-of-the-zone) states. Here we ask how different attentional states relate to the neural processing and transmission of task-relevant information. Specifically, during in-the-zone periods: (1) Do neural representations of task stimuli have greater fidelity? (2) Is there increased communication of this stimulus information across large-scale brain networks? Finally, (3) can the influence of performance-contingent reward be differentiated from zone-based fluctuations? To address these questions, we used fMRI and representational similarity analysis during a visual sustained attention task (the gradCPT). Participants ( n = 16) viewed a series of city or mountain scenes, responding to cities (90% of trials) and withholding to mountains (10%). Representational similarity matrices, reflecting the similarity structure of the city exemplars ( n = 10), were computed from visual, attentional, and default mode networks. Representational fidelity (RF) and representational connectivity (RC) were quantified as the interparticipant reliability of representational similarity matrices within (RF) and across (RC) brain networks. We found that being in the zone was characterized by increased RF in visual networks and increasing RC between visual and attentional networks. Conversely, reward only increased the RC between the attentional and default mode networks. These results diverge with analogous analyses using functional connectivity, suggesting that RC and functional connectivity in tandem better characterize how different mental states modulate the flow of information throughout the brain.

scholarly journals The effects of acute fluoxetine administration on temporal discounting in youth with ADHD

2015 ◽  
Vol 46 (6) ◽  
pp. 1197-1209 ◽  
Author(s):  
C. O. Carlisi ◽  
K. Chantiluke ◽  
L. Norman ◽  
A. Christakou ◽  
N. Barrett ◽  
...  
Keyword(s):  
Frontal Cortex ◽  
Repeated Measures ◽  
Premotor Cortex ◽  
Temporal Discounting ◽  
Drug Condition ◽  
Default Mode ◽  
Hyperactivity Disorder ◽  
Serotonin Agonist ◽  
Inferior Frontal Cortex ◽  
Randomized Design

BackgroundSerotonin is under-researched in attention deficit hyperactivity disorder (ADHD), despite accumulating evidence for its involvement in impulsiveness and the disorder. Serotonin further modulates temporal discounting (TD), which is typically abnormal in ADHD relative to healthy subjects, underpinned by reduced fronto-striato-limbic activation. This study tested whether a single acute dose of the selective serotonin reuptake inhibitor (SSRI) fluoxetine up-regulates and normalizes reduced fronto-striato-limbic neurofunctional activation in ADHD during TD.MethodTwelve boys with ADHD were scanned twice in a placebo-controlled randomized design under either fluoxetine (between 8 and 15 mg, titrated to weight) or placebo while performing an individually adjusted functional magnetic resonance imaging TD task. Twenty healthy controls were scanned once. Brain activation was compared in patients under either drug condition and compared to controls to test for normalization effects.ResultsRepeated-measures whole-brain analysis in patients revealed significant up-regulation with fluoxetine in a large cluster comprising right inferior frontal cortex, insula, premotor cortex and basal ganglia, which further correlated trend-wise with TD performance, which was impaired relative to controls under placebo, but normalized under fluoxetine. Fluoxetine further down-regulated default mode areas of posterior cingulate and precuneus. Comparisons between controls and patients under either drug condition revealed normalization with fluoxetine in right premotor-insular-parietal activation, which was reduced in patients under placebo.ConclusionsThe findings show that a serotonin agonist up-regulates activation in typical ADHD dysfunctional areas in right inferior frontal cortex, insula and striatum as well as down-regulating default mode network regions in the context of impulsivity and TD.

scholarly journals Surface-Based Information Mapping Reveals Crossmodal Vision–Action Representations in Human Parietal and Occipitotemporal Cortex

2010 ◽  
Vol 104 (2) ◽  
pp. 1077-1089 ◽  
Author(s):  
Nikolaas N. Oosterhof ◽  
Alison J. Wiggett ◽  
Jörn Diedrichsen ◽  
Steven P. Tipper ◽  
Paul E. Downing
Keyword(s):  
Neural Coding ◽  
Mirror Neurons ◽  
Human Action ◽  
Motor Representation ◽  
Multivoxel Pattern Analysis ◽  
Neural Representations ◽  
Postcentral Gyrus ◽  
Data Driven Approach ◽  
Occipitotemporal Cortex ◽  
Study Participants

Many lines of evidence point to a tight linkage between the perceptual and motoric representations of actions. Numerous demonstrations show how the visual perception of an action engages compatible activity in the observer's motor system. This is seen for both intransitive actions (e.g., in the case of unconscious postural imitation) and transitive actions (e.g., grasping an object). Although the discovery of “mirror neurons” in macaques has inspired explanations of these processes in human action behaviors, the evidence for areas in the human brain that similarly form a crossmodal visual/motor representation of actions remains incomplete. To address this, in the present study, participants performed and observed hand actions while being scanned with functional MRI. We took a data-driven approach by applying whole-brain information mapping using a multivoxel pattern analysis (MVPA) classifier, performed on reconstructed representations of the cortical surface. The aim was to identify regions in which local voxelwise patterns of activity can distinguish among different actions, across the visual and motor domains. Experiment 1 tested intransitive, meaningless hand movements, whereas experiment 2 tested object-directed actions (all right-handed). Our analyses of both experiments revealed crossmodal action regions in the lateral occipitotemporal cortex (bilaterally) and in the left postcentral gyrus/anterior parietal cortex. Furthermore, in experiment 2 we identified a gradient of bias in the patterns of information in the left hemisphere postcentral/parietal region. The postcentral gyrus carried more information about the effectors used to carry out the action (fingers vs. whole hand), whereas anterior parietal regions carried more information about the goal of the action (lift vs. punch). Taken together, these results provide evidence for common neural coding in these areas of the visual and motor aspects of actions, and demonstrate further how MVPA can contribute to our understanding of the nature of distributed neural representations.

scholarly journals Recruitment of the default mode network during a demanding act of executive control

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Ben M Crittenden ◽  
Daniel J Mitchell ◽  
John Duncan
Keyword(s):  
Executive Control ◽  
Default Mode Network ◽  
Pattern Analysis ◽  
Relevant Information ◽  
Multivoxel Pattern Analysis ◽  
Default Mode ◽  
Cognitive Context ◽  
Increased Activity ◽  
Reduced Activity ◽  
Or Task

In the human brain, a default mode or task-negative network shows reduced activity during many cognitive tasks and is often associated with internally-directed processes, such as mind wandering and thoughts about the self. In contrast to this task-negative pattern, we show increased activity during a large and demanding switch in task set. Furthermore, we employ multivoxel pattern analysis and find that regions of interest within default mode network are encoding task-relevant information during task performance. Activity in this network may be driven by major revisions of cognitive context, whether internally or externally focused.

β-conjugation of gadolinium(III) DOTA complexes to zinc(II) porpholactol as potential multimodal imaging contrast agents

2014 ◽  
Vol 18 (10n11) ◽  
pp. 950-959 ◽  
Author(s):  
Xian-Sheng Ke ◽  
Juan Tang ◽  
Zi-Shu Yang ◽  
Jun-Long Zhang
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Contrast Agents ◽  
Aqueous Media ◽  
Resonance Imaging ◽  
Bimodal Imaging ◽  
Imaging Experiment ◽  
Meso Position ◽  
Magnetic Resonance Imaging Mri ◽  
Magnetic Resonance Imaging Experiment

Synthesis of two bimodal imaging agents consist of a hydrophobic zinc(II) tetrapentafluorophenylporpholactol core and a β-substituted hydrophilic Gd ( III ) DO3A (ZnLGd539) or DOTA (ZnLGd595) like moiety has been described (DO3A = 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid, DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid). Through β-conjugation approach, the absorption at deep red region increases compared to traditional conjugation methods at meso-position. More importantly, these new complexes possess largely improved ionic relaxitivites relative to the sole Gd ( III ) magnetic resonance imaging (MRI) agents such as Gd ( III ) DO3A and Gd ( III ) DOTA like complexes. Combining the optical and magnetic resonance measurements in aqueous media, the largely enhanced r1 relaxivities was attributed to the aggregation of ZnLGd539 and ZnLGd595 in aqueous media. Furthermore, fluorescence and magnetic resonance imaging experiment showed that both ZnLGd539 and ZnLGd595 can be applied as potential bimodal imaging contrast agents. Finally, both compounds showed no dark cytotoxicity and good photocytotoxicity (IC50 = 1.73 ± 0.13 and 1.52 ± 0.10 μM for ZnLGd539 and ZnLGd595 respectively) on Hela cells.

scholarly journals The Cerebral Response during Subjective Choice with and without Self-reference

2005 ◽  
Vol 17 (12) ◽  
pp. 1897-1906 ◽  
Author(s):  
Sterling C. Johnson ◽  
Taylor W. Schmitz ◽  
Tisha N. Kawahara-Baccus ◽  
Howard A. Rowley ◽  
Andrew L. Alexander ◽  
...  
Keyword(s):  
Decision Making ◽  
Perspective Taking ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Neural Processes ◽  
Imaging Experiment ◽  
Color Similarity ◽  
Response Alternatives ◽  
Magnetic Resonance Imaging Experiment ◽  
Self Reference

The anterior medial prefrontal (AMPFC) and retrosplenial (RSC) cortices are active during self-referential decision-making tasks such as when participants appraise traits and abilities, or current affect. Other appraisal tasks requiring an evaluative decision or mental representation, such as theory of mind and perspective-taking tasks, also involve these regions. In many instances, these types of decisions involve a subjective opinion or preference, but also a degree of ambiguity in the decision, rather than a strictly veridical response. However, this ambiguity is generally not controlled for in studies that examine self-referential decision-making. In this functional magnetic resonance imaging experiment with 17 healthy adults, we examined neural processes associated with subjective decision-making with and without an overt self-referential component. The task required subjective decisions about colors-regarding self-preference (internal subjective decision) or color similarity (external subjective decision) under conditions where there was no objectively correct response. Results indicated greater activation in the AMPFC, RSC, and caudate nucleus during internal subjective decision-making. The findings suggest that self-referential processing, rather than subjective judgments among ambiguous response alternatives, accounted for the AMPFC and RSC response.

scholarly journals Puddles, Parties, and Professors: Linking Word Categorization to Neural Patterns of Visuospatial Coding

2011 ◽  
Vol 23 (10) ◽  
pp. 2636-2649 ◽  
Author(s):  
Susanne Quadflieg ◽  
Joset A. Etzel ◽  
Valeria Gazzola ◽  
Christian Keysers ◽  
Thomas W. Schubert ◽  
...  
Keyword(s):  
Word Processing ◽  
Parietal Lobe ◽  
Pattern Transfer ◽  
Multivoxel Pattern Analysis ◽  
Conceptual Processing ◽  
Visual Coding ◽  
Word Categorization ◽  
Geometrical Shapes ◽  
Behavioral Evidence ◽  
Discriminatory Information

Behavioral evidence suggests that during word processing people spontaneously map object, valence, and power information to locations in vertical space. Specifically, whereas “overhead” (e.g., attic), positive (e.g., party), and powerful nouns (e.g., professor) are associated with “up,” “underfoot” (e.g., carpet), negative (e.g., accident), and powerless nouns (e.g., assistant) are associated with “down.” What has yet to be elucidated, however, is the precise nature of these effects. To explore this issue, an fMRI experiment was undertaken, during which participants were required to categorize the position in which geometrical shapes appeared on a computer screen (i.e., upper or lower part of the display). In addition, they also judged a series of words with regard to location (i.e., up vs. down), valence (i.e., good vs. bad), and power (i.e., powerful vs. powerless). Using multivoxel pattern analysis, it was found that classifiers that successfully distinguished between the positions of shapes in subregions of the inferior parietal lobe also provided discriminatory information to separate location and valence, but not power word judgments. Correlational analyses further revealed that, for location words, pattern transfer was more successful the stronger was participants' propensity to use visual imagery. These findings indicate that visual coding and conceptual processing can elicit common representations of verticality but that divergent mechanisms may support the reported effects.

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