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  1. Article ; Online: Accelerated forgetting of a trauma-like event in healthy men and women after a single dose of hydrocortisone.

    Hennessy, Vanessa E / Troebinger, Luzia / Iskandar, Georges / Das, Ravi K / Kamboj, Sunjeev K

    Translational psychiatry

    2022  Volume 12, Issue 1, Page(s) 354

    Abstract: Posttraumatic stress disorder (PTSD) is characterised by dysregulated hypothalamic-pituitary-adrenal axis activity and altered glucocorticoid receptor sensitivity. Early treatment with glucocorticoids may reduce PTSD risk, although the effect of such ... ...

    Abstract Posttraumatic stress disorder (PTSD) is characterised by dysregulated hypothalamic-pituitary-adrenal axis activity and altered glucocorticoid receptor sensitivity. Early treatment with glucocorticoids may reduce PTSD risk, although the effect of such treatment on the aetiologically critical step of traumatic-memory-formation remains unclear. Here we examine the effects of exogenous cortisol (hydrocortisone) in a preclinical model of PTSD, using a factorial (Drug × Sex), randomised-controlled, double-blind design. Healthy men and women (n = 120) were randomised to receive 30 mg oral hydrocortisone or matched placebo immediately after watching a stressful film. Effects on film-related intrusions were assessed acutely in the lab, and ecologically using daily memory diaries for one week. We found that participants receiving hydrocortisone showed a faster reduction in daily intrusion frequency. Voluntary memory was assessed once, at the end of the week, but was unaffected by hydrocortisone. Exploratory analyses indicated sex-dependent associations between intrusions and baseline estradiol and progesterone levels. In men receiving hydrocortisone, higher baseline estradiol levels were associated with fewer intrusions, whereas women exhibited the opposite pattern. By contrast, progesterone levels were positively associated with intrusions only in men treated with hydrocortisone. The findings suggest that hydrocortisone promotes an accelerated degradation of sensory-perceptual representations underlying traumatic intrusive memories. In addition, while sex alone was not an important moderator, the combination of sex and sex-hormone levels (especially estradiol) influenced hydrocortisone's effects on involuntary aversive memories. Future well-powered experimental studies may provide a basis for a precision-psychiatry approach to optimising early post-traumatic glucocorticoid treatments that target intrusive memories, based on individual endocrinological profiles.
    MeSH term(s) Estradiol/pharmacology ; Female ; Humans ; Hydrocortisone/metabolism ; Hypothalamo-Hypophyseal System/metabolism ; Male ; Memory ; Pituitary-Adrenal System/metabolism ; Progesterone/pharmacology ; Stress Disorders, Post-Traumatic/drug therapy
    Chemical Substances Progesterone (4G7DS2Q64Y) ; Estradiol (4TI98Z838E) ; Hydrocortisone (WI4X0X7BPJ)
    Language English
    Publishing date 2022-08-31
    Publishing country United States
    Document type Journal Article ; Randomized Controlled Trial ; Research Support, Non-U.S. Gov't
    ZDB-ID 2609311-X
    ISSN 2158-3188 ; 2158-3188
    ISSN (online) 2158-3188
    ISSN 2158-3188
    DOI 10.1038/s41398-022-02126-2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Rewarding Subjective Effects of the NMDAR Antagonist Nitrous Oxide (Laughing Gas) Are Moderated by Impulsivity and Depressive Symptoms in Healthy Volunteers.

    Kamboj, Sunjeev K / Zhao, Hannah / Troebinger, Luzia / Piazza, Giulia / Cawley, Emma / Hennessy, Vanessa / Iskandar, Georges / Das, Ravi K

    The international journal of neuropsychopharmacology

    2021  Volume 24, Issue 7, Page(s) 551–561

    Abstract: Background: Nitrous oxide (N2O) is an anesthetic gas with both therapeutic and abuse potential. Because N2O is an NMDA receptor (NMDAR) antagonist, its effects are expected to resemble those of the prototypical NMDAR antagonist, ketamine. In this study, ...

    Abstract Background: Nitrous oxide (N2O) is an anesthetic gas with both therapeutic and abuse potential. Because N2O is an NMDA receptor (NMDAR) antagonist, its effects are expected to resemble those of the prototypical NMDAR antagonist, ketamine. In this study, we examined the subjective rewarding effects of N2O using measures previously employed in studies of ketamine. We also tested for moderation of these effects by bipolar phenotype, depressive symptoms, and impulsivity.
    Methods: Healthy volunteers were randomly assigned to either 50% N2O (n = 40) or medical air (n = 40). Self-reported rewarding (liking and wanting), and alcohol-like effects were assessed pre-, peri- and post inhalation.
    Results: Effect sizes for the various rewarding/alcohol-like effects of N2O were generally similar to those reported in studies of moderate-dose ketamine. Impulsivity moderated the subjective reinforcing (liking) effects of inhaled gas, while depressive symptoms moderated motivational (wanting [more]) effects. However, depression and impulsivity had opposite directional influences, such that higher impulsivity was associated with higher N2O liking, and higher depression, with lower N2O wanting.
    Conclusion: To the extent that static (versus longitudinal) subjective rewarding effects are a reliable indicator of future problematic drug use, our findings suggests that impulsivity and depression may predispose and protect, respectively, against N2O abuse. Future studies should examine if these moderators are relevant for other NMDAR antagonists, including ketamine, and novel ketamine-like therapeutic and recreational drugs. Similarities between moderate-dose N2O and moderate-dose ketamine in the intensity of certain subjective effects suggest that N2O may, at least to some extent, serve as substitute for ketamine as a safe and easily implemented experimental tool for probing reward-related NMDAR function and dysfunction in humans.
    MeSH term(s) Adult ; Depression/physiopathology ; Excitatory Amino Acid Antagonists/pharmacology ; Female ; Healthy Volunteers ; Humans ; Impulsive Behavior/physiology ; Male ; Nitrous Oxide/pharmacology ; Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors ; Reward ; Young Adult
    Chemical Substances Excitatory Amino Acid Antagonists ; Receptors, N-Methyl-D-Aspartate ; Nitrous Oxide (K50XQU1029)
    Language English
    Publishing date 2021-03-05
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1440129-0
    ISSN 1469-5111 ; 1461-1457
    ISSN (online) 1469-5111
    ISSN 1461-1457
    DOI 10.1093/ijnp/pyab009
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Neuromagnetic effects of pico-Tesla stimulation.

    Troebinger, Luzia / Anninos, Photios / Barnes, Gareth

    Physiological measurement

    2015  Volume 36, Issue 9, Page(s) 1901–1912

    Abstract: We used a double-blind experimental design to look for an effect of pico-Tesla magnetic stimulation in healthy subjects. Pico-Tesla stimulation is thought to increase the dominant frequency of 2-7 Hz oscillations in the human brain. We used ... ...

    Abstract We used a double-blind experimental design to look for an effect of pico-Tesla magnetic stimulation in healthy subjects. Pico-Tesla stimulation is thought to increase the dominant frequency of 2-7 Hz oscillations in the human brain. We used magnetoencephalography to measure resting state brain activity. Each subject had two separate recording sessions consisting of three runs in between which they were given real or sham pT stimulation. We then tried to predict the real and sham stimulation sessions based on changes in the mean peak frequency in the 2-7 Hz band. Our predictions for these individual runs were 8 out of 14 at chance level (p = 0.39). After unblinding, we found no significant effect (p = 0.11) of an increase in the frequency range (2-7 Hz) across the subject group. Finally, we performed a Bayesian model comparison between the effect size predicted from previous clinical studies and a null model. Even though this study had a sensitivity advantage of at least one order of magnitude over previous work, we found the null model to be significantly (2000 times) more likely.
    MeSH term(s) Adult ; Bayes Theorem ; Brain/physiology ; Double-Blind Method ; Humans ; Magnetic Fields ; Magnetic Resonance Imaging ; Magnetoencephalography ; Male ; Middle Aged ; Rest ; Transcranial Magnetic Stimulation ; Young Adult
    Language English
    Publishing date 2015-09
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1149545-5
    ISSN 1361-6579 ; 0967-3334
    ISSN (online) 1361-6579
    ISSN 0967-3334
    DOI 10.1088/0967-3334/36/9/1901
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Discrimination of cortical laminae using MEG.

    Troebinger, Luzia / López, José David / Lutti, Antoine / Bestmann, Sven / Barnes, Gareth

    NeuroImage

    2014  Volume 102 Pt 2, Page(s) 885–893

    Abstract: ... will tend to bias layer estimates. We then use a 3D printed head-cast (Troebinger et al., 2014) to achieve ...

    Abstract Typically MEG source reconstruction is used to estimate the distribution of current flow on a single anatomically derived cortical surface model. In this study we use two such models representing superficial and deep cortical laminae. We establish how well we can discriminate between these two different cortical layer models based on the same MEG data in the presence of different levels of co-registration noise, Signal-to-Noise Ratio (SNR) and cortical patch size. We demonstrate that it is possible to make a distinction between superficial and deep cortical laminae for levels of co-registration noise of less than 2mm translation and 2° rotation at SNR > 11 dB. We also show that an incorrect estimate of cortical patch size will tend to bias layer estimates. We then use a 3D printed head-cast (Troebinger et al., 2014) to achieve comparable levels of co-registration noise, in an auditory evoked response paradigm, and show that it is possible to discriminate between these cortical layer models in real data.
    MeSH term(s) Cerebral Cortex/physiology ; Humans ; Magnetoencephalography ; Male ; Signal-To-Noise Ratio
    Language English
    Publishing date 2014-07-17
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1147767-2
    ISSN 1095-9572 ; 1053-8119
    ISSN (online) 1095-9572
    ISSN 1053-8119
    DOI 10.1016/j.neuroimage.2014.07.015
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Cortical surface reconstruction based on MEG data and spherical harmonics.

    Lopez, Jose D / Troebinger, Luzia / Penny, Will / Espinosa, Jairo J / Barnes, Gareth R

    Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

    2013  Volume 2013, Page(s) 6449–6452

    Abstract: Estimates of coefficients of a spherical harmonic Fourier decomposition of the cortical surface can be obtained solely using MEG/EEG data and free energy as objective function. A stochastic methodology based on a Metropolis Search followed by a Bayesian ... ...

    Abstract Estimates of coefficients of a spherical harmonic Fourier decomposition of the cortical surface can be obtained solely using MEG/EEG data and free energy as objective function. A stochastic methodology based on a Metropolis Search followed by a Bayesian Model Averaging is proposed to reconstruct cortical anatomy based functional information.
    MeSH term(s) Algorithms ; Bayes Theorem ; Brain/pathology ; Brain Mapping/methods ; Computer Simulation ; Electroencephalography ; Fourier Analysis ; Humans ; Image Processing, Computer-Assisted ; Magnetoencephalography/methods ; Models, Theoretical ; Signal-To-Noise Ratio ; Stochastic Processes
    Language English
    Publishing date 2013-10-08
    Publishing country United States
    Document type Journal Article
    ISSN 2694-0604
    ISSN (online) 2694-0604
    DOI 10.1109/EMBC.2013.6611031
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: High precision anatomy for MEG.

    Troebinger, Luzia / López, José David / Lutti, Antoine / Bradbury, David / Bestmann, Sven / Barnes, Gareth

    NeuroImage

    2013  Volume 86, Page(s) 583–591

    Abstract: Precise MEG estimates of neuronal current flow are undermined by uncertain knowledge of the head location with respect to the MEG sensors. This is either due to head movements within the scanning session or systematic errors in co-registration to anatomy. ...

    Abstract Precise MEG estimates of neuronal current flow are undermined by uncertain knowledge of the head location with respect to the MEG sensors. This is either due to head movements within the scanning session or systematic errors in co-registration to anatomy. Here we show how such errors can be minimized using subject-specific head-casts produced using 3D printing technology. The casts fit the scalp of the subject internally and the inside of the MEG dewar externally, reducing within session and between session head movements. Systematic errors in matching to MRI coordinate system are also reduced through the use of MRI-visible fiducial markers placed on the same cast. Bootstrap estimates of absolute co-registration error were of the order of 1mm. Estimates of relative co-registration error were <1.5mm between sessions. We corroborated these scalp based estimates by looking at the MEG data recorded over a 6month period. We found that the between session sensor variability of the subject's evoked response was of the order of the within session noise, showing no appreciable noise due to between-session movement. Simulations suggest that the between-session sensor level amplitude SNR improved by a factor of 5 over conventional strategies. We show that at this level of coregistration accuracy there is strong evidence for anatomical models based on the individual rather than canonical anatomy; but that this advantage disappears for errors of greater than 5mm. This work paves the way for source reconstruction methods which can exploit very high SNR signals and accurate anatomical models; and also significantly increases the sensitivity of longitudinal studies with MEG.
    MeSH term(s) Brain Mapping/instrumentation ; Casts, Surgical ; Equipment Design ; Equipment Failure Analysis ; Head Protective Devices ; Humans ; Image Enhancement/instrumentation ; Magnetoencephalography/instrumentation ; Magnetoencephalography/methods ; Reproducibility of Results ; Restraint, Physical/instrumentation ; Restraint, Physical/methods ; Sensitivity and Specificity
    Language English
    Publishing date 2013-08-01
    Publishing country United States
    Document type Evaluation Study ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1147767-2
    ISSN 1095-9572 ; 1053-8119
    ISSN (online) 1095-9572
    ISSN 1053-8119
    DOI 10.1016/j.neuroimage.2013.07.065
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Does function fit structure? A ground truth for non-invasive neuroimaging.

    Stevenson, Claire / Brookes, Matthew / López, José David / Troebinger, Luzia / Mattout, Jeremie / Penny, William / Morris, Peter / Hillebrand, Arjan / Henson, Richard / Barnes, Gareth

    NeuroImage

    2014  Volume 94, Page(s) 89–95

    Abstract: There are now a number of non-invasive methods to image human brain function in-vivo. However, the accuracy of these images remains unknown and can currently only be estimated through the use of invasive recordings to generate a functional ground truth. ... ...

    Abstract There are now a number of non-invasive methods to image human brain function in-vivo. However, the accuracy of these images remains unknown and can currently only be estimated through the use of invasive recordings to generate a functional ground truth. Neuronal activity follows grey matter structure and accurate estimates of neuronal activity will have stronger support from accurate generative models of anatomy. Here we introduce a general framework that, for the first time, enables the spatial distortion of a functional brain image to be estimated empirically. We use a spherical harmonic decomposition to modulate each cortical hemisphere from its original form towards progressively simpler structures, ending in an ellipsoid. Functional estimates that are not supported by the simpler cortical structures have less inherent spatial distortion. This method allows us to compare directly between magnetoencephalography (MEG) source reconstructions based upon different assumption sets without recourse to functional ground truth.
    MeSH term(s) Algorithms ; Brain Mapping/methods ; Computer Simulation ; Gray Matter/anatomy & histology ; Gray Matter/physiology ; Humans ; Magnetoencephalography/methods ; Models, Anatomic ; Models, Neurological ; Reproducibility of Results ; Sensitivity and Specificity
    Language English
    Publishing date 2014-03-14
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1147767-2
    ISSN 1095-9572 ; 1053-8119
    ISSN (online) 1095-9572
    ISSN 1053-8119
    DOI 10.1016/j.neuroimage.2014.02.033
    Database MEDical Literature Analysis and Retrieval System OnLINE

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