GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Dissociable Systems for Gain- and Loss-Related Value Predictions and Errors of Prediction in the Human Brain
    Society for Neuroscience ; 2006
    In:  The Journal of Neuroscience Vol. 26, No. 37 ( 2006-09-13), p. 9530-9537
    Details
    In: The Journal of Neuroscience, Society for Neuroscience, Vol. 26, No. 37 ( 2006-09-13), p. 9530-9537
    Abstract: Midbrain dopaminergic neurons projecting to the ventral striatum code for reward magnitude and probability during reward anticipation and then indicate the difference between actual and predicted outcome. It has been questioned whether such a common system for the prediction and evaluation of reward exists in humans. Using functional magnetic resonance imaging and a guessing task in two large cohorts, we are able to confirm ventral striatal responses coding both reward probability and magnitude during anticipation, permitting the local computation of expected value (EV). However, the ventral striatum only represented the gain-related part of EV (EV + ). At reward delivery, the same area shows a reward probability and magnitude-dependent prediction error signal, best modeled as the difference between actual outcome and EV + . In contrast, loss-related expected value (EV − ) and the associated prediction error was represented in the amygdala. Thus, the ventral striatum and the amygdala distinctively process the value of a prediction and subsequently compute a prediction error for gains and losses, respectively. Therefore, a homeostatic balance of both systems might be important for generating adequate expectations under uncertainty. Prevalence of either part might render expectations more positive or negative, which could contribute to the pathophysiology of mood disorders like major depression.
    Type of Medium: Online Resource
    ISSN: 0270-6474 , 1529-2401
    URL: Article
    DOI: 10.1523/JNEUROSCI.2915-06.2006
    Language: English
    Publisher: Society for Neuroscience
    Publication Date: 2006
    detail.hit.zdb_id: 1475274-8
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    CO 2 signaling in guard cells: Calcium sensitivity response modulation, a Ca 2+ -independent phase, and CO 2 insensitivity of the gca2 mutant
    Proceedings of the National Academy of Sciences ; 2006
    In:  Proceedings of the National Academy of Sciences Vol. 103, No. 19 ( 2006-05-09), p. 7506-7511
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 103, No. 19 ( 2006-05-09), p. 7506-7511
    Abstract: Leaf stomata close in response to high carbon dioxide levels and open at low CO 2 . CO 2 concentrations in leaves are altered by daily dark/light cycles, as well as the continuing rise in atmospheric CO 2 . Relative to abscisic acid and blue light signaling, little is known about the molecular, cellular, and genetic mechanisms of CO 2 signaling in guard cells. Interestingly, we report that repetitive Ca 2+ transients were observed during the stomatal opening stimulus, low [CO 2 ]. Furthermore, low/high [CO 2 ] transitions modulated the cytosolic Ca 2+ transient pattern in Arabidopsis guard cells (Landsberg erecta ). Inhibition of cytosolic Ca 2+ transients, achieved by loading guard cells with the calcium chelator 1,2-bis(2-aminophenoxy)ethane- N,N,N′,N′ -tetraacetic acid and not adding external Ca 2+ , attenuated both high CO 2 -induced stomatal closing and low CO 2 -induced stomatal opening, and also revealed a Ca 2+ -independent phase of the CO 2 response. Furthermore, the mutant, growth controlled by abscisic acid ( gca2 ) shows impairment in [CO 2 ] modulation of the cytosolic Ca 2+ transient rate and strong impairment in high CO 2 -induced stomatal closing. Our findings provide insights into guard cell CO 2 signaling mechanisms, reveal Ca 2+ -independent events, and demonstrate that calcium elevations can participate in opposed signaling events during stomatal opening and closing. A model is proposed in which CO 2 concentrations prime Ca 2+ sensors, which could mediate specificity in Ca 2+ signaling.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0602225103
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2006
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Differential induction of BLT receptor expression on human endothelial cells by lipopolysacharide, cytokines, and leukotriene B 4
    Proceedings of the National Academy of Sciences ; 2006
    In:  Proceedings of the National Academy of Sciences Vol. 103, No. 18 ( 2006-05-02), p. 6913-6918
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 103, No. 18 ( 2006-05-02), p. 6913-6918
    Abstract: Leukotriene (LT) B 4 is a powerful chemotactic and immune modulating agent that signals via two receptors denoted BLT 1 and BLT 2 . Here we report that BLT 1 and BLT 2 are expressed at low levels in an apparently silent state in human umbilical vein endothelial cells (HUVEC). However, treatment with LPS leads to a 〉 10 fold increase in the levels of BLT 1 mRNA without any significant effects on BLT 2 mRNA. In parallel, LPS also increases the amounts of BLT 1 protein. Tumor necrosis factor-α (TNF-α) increases the expression of BLT 2 mRNA ≈6 times above basal levels with only a modest increase in BLT 1 mRNA. Interleukin-1β causes variable and parallel increases of both BLT 1 and BLT 2 mRNA. The natural ligand LTB 4 also increases BLT 1 , but not BLT 2 , mRNA and protein expression. Along with the induction of BLT 1 and/or BLT 2 , HUVEC acquire the capacity to respond to LTB 4 with increased levels of intracellular calcium and these signals can be blocked by isotype selective BLT antagonists, CP-105696 and LY-255283. In addition, treatment of HUVEC with LTB 4 causes increased release of both nitrite, presumably reflecting nitric oxide (NO), and monocyte chemoattractant protein-1. Our data indicate that expression of functional BLT receptors may occur at the surface of endothelial cells in response to LPS, cytokines, and ligand, which in turn may have functional consequences during the early vascular responses to inflammation. Moreover, the results point to BLT receptors as potential targets for pharmacological intervention in LT-dependent inflammatory diseases such as asthma, rheumatoid arthritis, and arteriosclerosis.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0602208103
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2006
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Gene–gene interaction associated with neural reward sensitivity
    Proceedings of the National Academy of Sciences ; 2007
    In:  Proceedings of the National Academy of Sciences Vol. 104, No. 19 ( 2007-05-08), p. 8125-8130
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 104, No. 19 ( 2007-05-08), p. 8125-8130
    Abstract: Reward processing depends on dopaminergic neurotransmission and is modulated by factors affecting dopamine (DA) reuptake and degradation. We used fMRI and a guessing task sensitive to reward-related activation in the prefrontal cortex and ventral striatum to study how individual variation in genes contributing to DA reuptake [DA transporter (DAT)] and degradation [catechol-o-methyltransferase (COMT)] influences reward processing. Prefrontal activity, evoked by anticipation of reward irrespective of reward probability and magnitude, was COMT genotype-dependent. Volunteers homozygous for the Met allele, associated with lower enzyme activity and presumably greater DA availability, showed larger responses compared with volunteers homozygous for the Val allele. A similar COMT effect was observed in the ventral striatum. As reported previously, the ventral striatum was also found to code gain-related expected value, i.e., the product of reward magnitude and gain probability. Individual differences in ventral striatal sensitivity for value were in part explained by an epistatic gene–gene interaction between COMT and DAT. Although most genotype combinations exhibited the expected activity increase with more likely and larger rewards, two genotype combinations (COMT Met/Met DAT 10R and COMT Val/Val 9R) were associated with blunted ventral striatal responses. In view of a consistent relationship between reduced reward sensitivity and addiction, our findings point to a potential genetic basis for vulnerability to addiction.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0702029104
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2007
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...